Introduction to Networks

Protocol Data Units (PDU)

**Note: If the Transport header is TCP, then it is segment. If the Transport header is UDP then it is a datagram. -As application data is passed down the protocol stack on its way to be transmitted across the network media, various protocol information is added at each level. This is known as the encapsulation process. **Note: Although the UDP PDU is called datagram, IP packets are sometimes also referred to as IP datagrams. -The form that a piece of data takes at any layer is called a protocol data unit (PDU). -During encapsulation, each succeeding layer encapsulates the PDU that it receives from the layer above in accordance with the protocol being used. At each stage of the process, a PDU has a different name to reflect its new functions. Although there is no universal naming convention for PDUs, in this course, the PDUs are named according to the protocols of the TCP/IP suite. -Data The general term for the PDU used at the application layer. -Segment Transport layer PDU -Packet Network layer PDU -Frame Data Link layer PDU -Bits Physical layer PDU used when physically transmitting data over the medium.

Terminal Emulation Programs

--These programs allow you to enhance your productivity by adjusting window sizes, changing font sizes, and changing color schemes. -There are several terminal emulation programs you can use to connect to a networking device either by a serial connection over a console port, or by an SSH/Telnet connection. • PuTTY • Tera Term • SecureCRT • OS X Terminal

LANs (Local Area Networks)

-A LAN is a network infrastructure that provides access to users and end devices in a small geographical area. -A LAN is typically used in a department within an enterprise, a home, or a small business network. -LANs provide high-speed bandwidth to internal end devices and intermediary devices, as shown in the figure.

NIC (Network Interface Card)

-A NIC physically connects the end device to the network. -A device that serves as an interface between the computer and the network. -Also called a network adapter or network card.

Extrants

-A company that is providing access to outside suppliers and contractors -A hospital that is providing a booking system to doctors so they can make appointments for their patients -A local office of education that is providing budget and personnel information to the schools in its district

Duplex Multimode LC Connectors

-A duplex multimode LC connector is similar to a LC simplex connector, but uses a duplex connector. -Until recently, light could only travel in one direction over optical fiber. Two fibers were required to support the full duplex operation. Therefore, fiber-optic patch cables bundle together two optical fiber cables and terminate them with a pair of standard, single-fiber connectors. Some fiber connectors accept both the transmitting and receiving fibers in a single connector known as a duplex connector, as shown in the Duplex Multimode LC Connector in the figure. BX standards such as 100BASE-BX use different wavelengths for sending and receiving over a single fiber.

Evolution Of Protocol Suites

-A protocol suite is a set of protocols that work together to provide comprehensive network communication services. -Internet Protocol Suite or TCP/IP This is the most common and relevant protocol suite today. The TCP/IP protocol suite is an open standard protocol suite maintained by the Internet Engineering Task Force (IETF). -Open System Interconnection (OSI) Protocols This is a family of protocols developed jointly in 1977 by the International Organization for Standardization (IOS) and the International Telecommunications Union (ITU). The OSI protocol also included a 7 year model called the OSI reference model. The OSI protocols have largely been replaced by TCP/IP. -AppleTalk A short-lived proprietary protocol suite released by Apple Inc. in 1985 for Apple devices. In 1995, Apple adopted TCP/IP to replace AppleTalk. -Novell NetWare A short-lived proprietary protocol suite and network operating system developed by Novell Inc. in 1983 using the IPX network protocol. In 1995, Novell adopted TCP/IP to replace IPX.

QoS (Quality of Service)

-A set of parameters that controls the level of quality provided to different types of network traffic. -Quality of Service (QoS) is an increasing requirement of networks today. New applications available to users over networks, such as voice and live video transmissions, create higher expectations for the quality of the delivered services. -Have you ever tried to watch a video with constant breaks and pauses? As data, voice, and video content continue to converge onto the same network, QoS becomes a primary mechanism for managing congestion and ensuring reliable delivery of content to all users. -Congestion occurs when the demand for bandwidth exceeds the amount available. -Network bandwidth is measured in the number of bits that can be transmitted in a single second, or bits per second (bps). -When simultaneous communications are attempted across the network, the demand for network bandwidth can exceed its availability, creating network congestion. When the volume of traffic is greater than what can be transported across the network, devices will hold the packets in memory until resources become available to transmit them. In the figure, one user is requesting a web page, and another is on a phone call. With a QoS policy in place, the router can manage the flow of data and voice traffic, giving priority to voice communications if the network experiences congestion. -The focus of QoS is to prioritize time-sensitive traffic. The type of traffic, not the content of the traffic, is what is important.

Access Methods

-A switch will forward traffic by default and does not need to be explicitly configured to operate. For example, two configured hosts connected to the same new switch would be able to communicate. Regardless of the default behavior of a new switch, all switches should be configured and secured. -Console This is a physical management port that provides out-of-band access to a Cisco device. Out-of-band access refers to access via a dedicated management channel that is used for device maintenance purposes only. The advantage of using a console port is that the device is accessible even if no networking services are configured, such as performing the initial configuration. A computer running terminal emulation software and a special console cable to connect to the device are required for a console connection. -Secure Shell (SSH) SSH is an in-band and recommended method for remotely establishing a secure CLI connection, through a virtual interface, over a network. Unlike a console connection, SSH connections require active networking services on the device, including an active interface configured with an address. Most versions of Cisco IOS include an SSH server and an SSH client that can be used to establish SSH sessions with other devices. -Telnet Telnet is an insecure, in-band method of remotely establishing a CLI session, through a virtual interface, over a network. Unlike SSH, Telnet does not provide a secure, encrypted connection and should only be used in a lab environment. User authentication, passwords, and commands are sent over the network in plaintext. The best practice is to use SSH instead of Telnet. Cisco IOS includes both a Telnet server and Telnet client. **Note: Some devices, such as routers, may also support a legacy auxiliary port that was used to establish a CLI session remotely over a telephone connection using a modem. Similar to a console connection, the AUX port is out-of-band and does not require networking services to be configured or available.

Graphical User Interface (GUI)

-A visual display on a computer's screen that allows you to interact with your computer more easily by clicking graphical elements. -A GUI such as Windows, macOS, Linux KDE, Apple iOS, or Android allows the user to interact with the system using an environment of graphical icons, menus, and windows. The GUI example in the figure is more user-friendly and requires less knowledge of the underlying command structure that controls the system. For this reason, most users rely on GUI environments. -GUI may not always be able to provide all the features available with the CLI. -GUIs can also fail, crash, or simply not operate as specified. -The CLI is less resource intense and very stable when compared to GUI.

What Layer 2 function does a router perform?

-Accepts a frame from a medium -De-encapsulates the frame. -Re-encapsulates the packet into a new frame. -Forwards the new frame appropriate to the medium of that segment of the physical network

Network Protocol Functions

-Addressing This identifies the sender and the intended receiver of the message using a defined addressing scheme. Examples of protocols that provide addressing include Ethernet, IPv4, and IPv6. -Reliability This function provides guaranteed delivery mechanisms in case messages are lost or corrupted in transit. TCP provides guaranteed delivery. -Flow control This function ensures that data flows at an efficient rate between two communicating devices. TCP provides flow control services. -Sequencing This function uniquely labels each transmitted segment of data. The receiving device uses the sequencing information to reassemble the information correctly. This is useful if the data segments are lost, delayed or received out-of-order. TCP provides sequencing services. -Error Detection This function is used to determine if data became corrupted during transmission. Various protocols that provide error detection include Ethernet, IPv4, IPv6, and TCP. -Application Interface This function contains information used for process-to-process communications between network applications. For example, when accessing a web page, HTTP or HTTPS protocols are used to communicate between the client and server web processes.

Operating Systems (OS)

-All end devices require an (OS). -Shell The user interface that allows users to request specific tasks from the computer. These requests can be made either through the CLI or GUI. -Kernel Communicates between the hardware and software of a computer and manages how hardware resources are used to meet software requirements. -Hardware The physical part of a computer including underlying electronics. -The user can interact with the shell using a command-line interface (CLI) or a graphical user interface (GUI). **Purpose of an OS** -Network operating systems are similar to a PC operating system. -Through GUI, a PC operating system enables users to do: ~~Use a mouse to. make selections and run programs. ~~Enter text and text-based commands. ~~View output on a monitor. -A CLI-based network operating system(e.g.,the Cisco IOS on a switch or router) enables a network technician to do: ~~Use a keyboard to run CLI-based network programs ~~Use a keyboard to enter text and text-based commands ~~View output on a monitor

Layer 3 - Logical Address

-An IP address is the network layer, or Layer 3, logical address used to deliver the IP packet from the original source to the final destination, as shown in the figure. The IP packet contains two IP addresses: Source IP address The IP address of the sending device, which is the original source of the packet. Destination IP address The IP address of the receiving device, which is the final destination of the packet. -The IP addresses indicate the original source IP address and final destination IP address. This is true whether the source and destination are on the same IP network or different IP networks. An IP address contains two parts: Network portion (IPv4) or Prefix (IPv6) The left-most part of the address that indicates the network in which the IP address is a member. All devices on the same network will have the same network portion of the address. Host portion (IPv4) or Interface ID (IPv6) The remaining part of the address that identifies a specific device on the network. This portion is unique for each device or interface on the network. **Note: The subnet mask (IPv4) or prefix-length (IPv6) is used to identify the network portion of an IP address from the host portion.

Fiber-Optic Connectors

-An optical-fiber connector terminates the end of an optical fiber. A variety of optical-fiber connectors are available. The main differences among the types of connectors are dimensions and methods of coupling. Businesses decide on the types of connectors that will be used, based on their equipment. -Note: Some switches and routers have ports that support fiber-optic connectors through a small form-factor pluggable (SFP) transceiver. Search the internet for various types of SFPs. -Straight-Tip (ST) Connectors -Subscriber Connector (SC) Connectors -Lucent Connector (LC) Simplex Connectors -Duplex Multimode LC Connectors

Security Solutions for a Home or Small Office.

-Antivirus and Antispyware These applications help to protect end devices from becoming infected with malicious software. -Firewall filtering Firewall filtering blocks unauthorized access into and out of the network. This may include a host-based firewall system that prevents unauthorized access to the end device, or a basic filtering service on the home router to prevent unauthorized access from the outside world into the network.

Primary Command Modes

-As a security feature, the Cisco IOS software separates management access into the following two command modes: -User EXEC Mode This mode has limited capabilities but is useful for basic operations. It allows only a limited number of basic monitoring commands but does not allow the execution of any commands that might change the configuration of the device. The user EXEC mode is identified by the CLI prompt that ends with the > symbol. -Privileged EXEC Mode To execute configuration commands, a network administrator must access privileged EXEC mode. Higher configuration modes, like global configuration mode, can only be reached from privileged EXEC mode. The privileged EXEC mode can be identified by the prompt ending with the # symbol.

Benefits of Using a Layered Model.. to describe network protocols and operations

-Assisting in protocol design because protocols that operate at a specific layer have defined information that they act upon and a defined interface to the layers above and below -Fostering competition because products from different vendors can work together -Preventing technology or capability changes in one layer from affecting other layers above and below -Providing a common language to describe networking functions and capabilities **Note: As shown in the figure, there are two layered models that are used to describe network operations: -Open System Interconnection (OSI) Reference Model -TCP/IP Reference Model

What type of communication will send a message to all devices on a local area network?

-BROADCAST -Broadcast communication is a one-to-all communication. A unicast communication is a one-to-one communication. Multicast is a one-to-many communication where the message is delivered to a specific group of hosts. Allcast is not a standard term to describe message delivery.

Which message delivery option is used when all devices need to receive the same message simultaneously?

-BROADCAST -When all devices need to receive the same message simultaneously, the message would be delivered as a broadcast. Unicast delivery occurs when one source host sends a message to one destination host. The sending of the same message from a host to a group of destination hosts is multicast delivery. Duplex communications refers to the ability of the medium to carry messages in both directions.

Properties of UTP Cabling

-Because UTP cabling is the standard for use in LANs, this topic goes into detail about its advantages and limitations, and what can be done to avoid problems. -When used as a networking medium, UTP cabling consists of four pairs of color-coded copper wires that have been twisted together and then encased in a flexible plastic sheath. Its small size can be advantageous during installation. UTP cable does not use shielding to counter the effects of EMI and RFI. Instead, cable designers have discovered other ways that they can limit the negative effect of crosstalk: -Cancellation - Designers now pair wires in a circuit. When two wires in an electrical circuit are placed close together, their magnetic fields are the exact opposite of each other. Therefore, the two magnetic fields cancel each other and also cancel out any outside EMI and RFI signals. -Varying the number of twists per wire pair - To further enhance the cancellation effect of paired circuit wires, designers vary the number of twists of each wire pair in a cable. UTP cable must follow precise specifications governing how many twists or braids are permitted per meter (3.28 feet) of cable. Notice in the figure that the orange/orange white pair is twisted less than the blue/blue white pair. Each colored pair is twisted a different number of times. -UTP cable relies solely on the cancellation effect produced by the twisted wire pairs to limit signal degradation and effectively provide self-shielding for wire pairs within the network media.

Which two commands would return you to the privileged EXEC prompt regardless of the configuration mode you are in? (Choose two.)

-CTRL+Z -End

Home & Small Office Internet Connections

-Cable high availability, high bandwidth, always-on connection to the internet. -DSL (digital Subscriber Lines) provide high bandwidth, high availability, an always on connection. Runs over telephone lines. Connect using ADSL (Asymmetrical DSL) which means download speed is faster than upload speed. -Cellular uses a cell phone network to connect. Wherever you can get a cellular signal you can get cellular internet access. Performances are limited by capabilities of the phone and the cell tower. -Satellite dishes require a clear line of sight to the satellite. Used when otherwise have no internet connections. -Dial-up Telephone inexpensive option that uses any phone line and a modem. Low bandwidth, not sufficient for large data transfer, although it is useful for mobile access while traveling.

Coaxial Cable

-Coaxial cable, or coax for short, gets its name from the fact that there are two conductors that share the same axis. As shown in the figure, coaxial cable consists of the following: -A copper conductor is used to transmit the electronic signals. -A layer of flexible plastic insulation surrounds a copper conductor. -The insulating material is surrounded in a woven copper braid, or metallic foil, that acts as the second wire in the circuit and as a shield for the inner conductor. This second layer, or shield, also reduces the amount of outside electromagnetic interference. -The entire cable is covered with a cable jacket to prevent minor physical damage. -There are different types of connectors used with coax cable. The Bayonet Neill-Concelman (BNC), N type, and F type connectors are shown in the figure. Although UTP cable has essentially replaced coaxial cable in modern Ethernet installations, the coaxial cable design is used in the following situations: -Wireless installations - Coaxial cables attach antennas to wireless devices. The coaxial cable carries radio frequency (RF) energy between the antennas and the radio equipment. -Cable internet installations - Cable service providers provide internet connectivity to their customers by replacing portions of the coaxial cable and supporting amplification elements with fiber-optic cable. However, the wiring inside the customer's premises is still coax cable. Three figures showing the construction of a coaxial cable, a cross-section of a coaxial cable, and three types of coaxial cable connectors. -BNC -N type -F type 1. Outer Jacket 2. Braided copper shielding 3. Plastic insulation 4. Copper conductor

Network Security

-Concerned with addressing vulnerabilities and threats in computer networks that may or may not be connected to the internet. -The network infrastructure, services, and the data contained on network-attached devices are crucial personal and business assets. Network administrators must address two types of network security concerns: network infrastructure security and information security. -Securing the network infrastructure includes physically securing devices that provide network connectivity and preventing unauthorized access to the management software that resides on them, as shown in the figure. -Network administrators must also protect the information contained within the packets being transmitted over the network, and the information stored on network attached devices. In order to achieve the goals of network security, there are three primary requirements.

Security Solutions for a Corporate Network

-Consists of many components built into the network. -Dedicated Firewall Systems These provide more advanced firewall capabilities that can filter large amounts of traffic with more granularity. -Access Control Lists (ACL) These further filter access and traffic forwarding based on IP addresses and applications. -Intrusion Prevention Systems (IPS) These identify fast-spreading threats, such as zero-day or zero-hour attacks. -Virtual Private Networks (VPN) These provide secure access into an organization for remote workers.

Which two functions are performed at the MAC sublayer of the OSI data link layer? (Choose two.)

-Controls the NIC responsible for sending and receiving data on the physical medium. -Provides a mechanism to allow multiple devices to communicate over a shared medium.

Characteristics of Copper Cabling

-Copper cabling is the most common type of cabling used in networks today. In fact, copper cabling is not just one type of cable. There are three different types of copper cabling that are each used in specific situations. -Networks use copper media because it is inexpensive, easy to install, and has low resistance to electrical current. However, copper media is limited by distance and signal interference. -Data is transmitted on copper cables as electrical pulses. A detector in the network interface of a destination device must receive a signal that can be successfully decoded to match the signal sent. However, the farther the signal travels, the more it deteriorates. This is referred to as signal attenuation. For this reason, all copper media must follow strict distance limitations as specified by the guiding standards. The timing and voltage values of the electrical pulses are also susceptible to interference from two sources: Electromagnetic interference (EMI) or radio frequency interference (RFI) - EMI and RFI signals can distort and corrupt the data signals being carried by copper media. Potential sources of EMI and RFI include radio waves and electromagnetic devices, such as fluorescent lights or electric motors. Crosstalk - Crosstalk is a disturbance caused by the electric or magnetic fields of a signal on one wire to the signal in an adjacent wire. In telephone circuits, crosstalk can result in hearing part of another voice conversation from an adjacent circuit. Specifically, when an electrical current flows through a wire, it creates a small, circular magnetic field around the wire, which can be picked up by an adjacent wire. The figure shows how data transmission can be affected by interference. 1. A pure digital signal is transmitted. 2. On the medium, there is an interface signal. 3. The digital signal is corrupted by the interface signal. 4. The receiving computer reads a changed signal. Notice that a 0 bit is now interpreted as 1 bit. -To counter the negative effects of EMI and RFI, some types of copper cables are wrapped in metallic shielding and require proper grounding connections. -To counter the negative effects of crosstalk, some types of copper cables have opposing circuit wire pairs twisted together, which effectively cancels the crosstalk. The susceptibility of copper cables to electronic noise can also be limited using these recommendations: -Selecting the cable type or category most suited to a given networking environment. -Designing a cable infrastructure to avoid known and potential sources of interference in the building structure. -Using cabling techniques that include the proper handling and termination of the cables.

Which two devices commonly affect wireless networks? (Choose two.)

-Cordless Phones -Microwaves

What process is used to receive transmitted data and convert it into a readable message?

-DECODING -Decoding is the process of receiving transmitted data and reversing the encoding process to interpret the information. An example is a person that listens to a voicemail and decodes the sounds to understand the received message.

Which logical address is used for delivery of data to a remote network?

-DESTINATION IP ADDRESS -The destination IP address is used for end-to-end delivery of data to a remote network. The destination MAC address is used for delivery on a local network. The destination port number identifies the application that should process the data at the destination. Source addresses identify the sender of the data.

Which two protocols are service discovery protocols?

-DNS -DHCP

Which two protocols belong in the TCP/IP model application layer?

-DNS -DHCP

Business Internet Connections

-Dedicated Leased Line Leased lines are reserved circuits within the service provider's network that connect geographically separated offices for private voice and/or data networking. The circuits are rented at a monthly or yearly rate. -Metro Ethernet This is sometimes known as Ethernet WAN. In this module, we will refer to it as Metro Ethernet. Metro ethernets extend LAN access technology into the WAN. Ethernet is a LAN technology you will learn about in a later module. -Business DSL Business DSL is available in various formats. A popular choice is Symmetric Digital Subscriber Line (SDSL) which is similar to the consumer version of DSL but provides uploads and downloads at the same high speeds. -Satellite Satellite service can provide a connection when a wired solution is not available.

Which two functions are provided to users by the context-sensitive help feature of the Cisco IOS CLI? (Choose two.)

-Determining which option, keyword, or argument is available for the entered command. -Displaying a list of all available commands within the current mode.

Bandwidth

-Different physical media support the transfer of bits at different rates. Data transfer is usually discussed in terms of bandwidth. Bandwidth is the capacity at which a medium can carry data. Digital bandwidth measures the amount of data that can flow from one place to another in a given amount of time. Bandwidth is typically measured in kilobits per second (kbps), megabits per second (Mbps), or gigabits per second (Gbps). Bandwidth is sometimes thought of as the speed that bits travel, however this is not accurate. For example, in both 10Mbps and 100Mbps Ethernet, the bits are sent at the speed of electricity. The difference is the number of bits that are transmitted per second. A combination of factors determines the practical bandwidth of a network: -The properties of the physical media -The technologies chosen for signaling and detecting network signals -Physical media properties, current technologies, and the laws of physics all play a role in determining the available bandwidth. -The table shows the commonly used units of measure for bandwidth.

Straight-through and Crossover UTP Cables

-Different situations may require UTP cables to be wired according to different wiring conventions. This means that the individual wires in the cable have to be connected in different orders to different sets of pins in the RJ-45 connectors. The following are the main cable types that are obtained by using specific wiring conventions: -Ethernet Straight-through - The most common type of networking cable. It is commonly used to interconnect a host to a switch and a switch to a router. Standard-Both ends T568A or both ends T568B -Ethernet Crossover - A cable used to interconnect similar devices. For example, to connect a switch to a switch, a host to a host, or a router to a router. However, crossover cables are now considered legacy as NICs use medium-dependent interface crossover (auto-MDIX) to automatically detect the cable type and make the internal connection. Standard-One end T568A, other end T568B -Rollover - A type of cable is a rollover cable, which is Cisco proprietary. Connects a workstation serial port to a router console port, using an adapter -Using a crossover or straight-through cable incorrectly between devices may not damage the devices, but connectivity and communication between the devices will not take place. This is a common error and checking that the device connections are correct should be the first troubleshooting action if connectivity is not achieved. -The figure identifies the individual wire pairs for the T568A and T568B standards.

What process is used to place one message inside another message for transfer from the source to the destination?

-ENCAPSULATION -Encapsulation is the process of placing one message format into another message format. An example is how a packet is placed in its entirety into the data field as it is encapsulated into a frame.

Signaling [Copper Cable]

-Electrical Signals Over Copper Cable -Networks use copper media because it is inexpensive, easy to install, and has low resistance to electrical current. However, copper media is limited by distance and signal interference. The timing and voltage values of the electrical pulses are also susceptible to interference from two sources: EMI and crosstalk. Three types of copper cabling are: UTP, STP, and coaxial cable (coax). UTP has an outer jacket to protect the copper wires from physical damage, twisted pairs to protect the signal from interference, and color-coded plastic insulation that electrically isolates wires from each other and identifies each pair. The STP cable uses four pairs of wires, each wrapped in a foil shield, which are then wrapped in an overall metallic braid or foil. Coaxial cable, or coax for short, gets its name from the fact that there are two conductors that share the same axis. Coax is used to attach antennas to wireless devices. Cable internet providers use coax inside their customers' premises.

Automatic IP Address Configuration for End Devices

-End devices typically default to using DHCP (Dynamic Host Configuration Protocol) for automatic IPv4 address configuration. DHCP is a technology that is used in almost every network. The best way to understand why DHCP is so popular is by considering all the extra work that would have to take place without it. -In a network, DHCP enables automatic IPv4 address configuration for every end device that is DHCP-enabled. Imagine the amount of time it would take if every time you connected to the network, you had to manually enter the IPv4 address, the subnet mask, the default gateway, and the DNS server. Multiply that by every user and every device in an organization and you see the problem. Manual configuration also increases the chance of misconfiguration by duplicating another device's IPv4 address. -As shown in the figure, to configure DHCP on a Windows PC, you only need to select Obtain an IP address automatically and Obtain DNS server address automatically. Your PC will search out a DHCP server and be assigned the address settings necessary to communicate on the network. **Note: IPv6 uses DHCPv6 and SLAAC (Stateless Address Autoconfiguration) for dynamic address allocation.

Access Control Methods

-Ethernet LANs and WLANs are examples of multiaccess networks. A multiaccess network is a network that can have two or more end devices attempting to access the network simultaneously. -Some multiaccess networks require rules to govern how devices share the physical media. There are two basic access control methods for shared media: -Contention-based access -Controlled access

What are three ways that media access control is used in networking? (Choose three.)

-Ethernet utilizes CSMA/CD -Media access control provides placement of data frames onto the media -Data link layer protocols define the rules for access to different media

What are two examples of the cut-through switching method? (Choose two.)

-Fast-forward switching -Fragment-free switching

Fiber Patch Cords

-Fiber patch cords are required for interconnecting infrastructure devices. The use of color distinguishes between single-mode and multimode patch cords. A yellow jacket is for single-mode fiber cables and orange (or aqua) for multimode fiber cables. -SC-SC Multimode Patch Cord -LC-LC Single-mode Patch Cord -ST-LC Multimode Patch Cord -SC-ST Single-mode Patch Cord

Properties of Fiber-Optic Cabling

-Fiber-optic cabling is the other type of cabling used in networks. Because it is expensive, it is not as commonly used at the various types of copper cabling. But fiber-optic cabling has certain properties that make it the best option in certain situations. -Optical fiber cable transmits data over longer distances and at higher bandwidths than any other networking media. Unlike copper wires, fiber-optic cable can transmit signals with less attenuation and is completely immune to EMI and RFI. Optical fiber is commonly used to interconnect network devices. -Optical fiber is a flexible, but extremely thin, transparent strand of very pure glass, not much bigger than a human hair. Bits are encoded on the fiber as light impulses. The fiber-optic cable acts as a waveguide, or "light pipe," to transmit light between the two ends with minimal loss of signal. -As an analogy, consider an empty paper towel roll with the inside coated like a mirror. It is a thousand meters in length, and a small laser pointer is used to send Morse code signals at the speed of light. Essentially that is how a fiber-optic cable operates, except that it is smaller in diameter and uses sophisticated light technologies.

Which are components of message timing? (Choose three.)

-Flow Control -Access Method -Response Timeout

Message Timing

-Flow Control - This is the process of managing the rate of data transmission. Flow control defines how much information can be sent and the speed at which it can be delivered. For example, if one person speaks too quickly, it may be difficult for the receiver to hear and understand the message. In network communication, there are network protocols used by the source and destination devices to negotiate and manage the flow of information. -Response Timeout - If a person asks a question and does not hear a response within an acceptable amount of time, the person assumes that no answer is coming and reacts accordingly. The person may repeat the question or instead, may go on with the conversation. Hosts on the network use network protocols that specify how long to wait for responses and what action to take if a response timeout occurs. -Access method - This determines when someone can send a message. When a device wants to transmit on a wireless LAN, it is necessary for the WLAN network interface card (NIC) to determine whether the wireless medium is available.

What makes fiber preferable to copper cabling for interconnecting buildings? (Choose three.)

-Greater distances per cable run -Limited susceptibility to EMI/RFI -Greater bandwidth potential

What are two characteristics of a scalable network? (Choose two.)

-Grows in size without impacting existing users -Suitable for modular devices that allow for expansion.

A web client is sending a request for a webpage to a web server. From the perspective of the client, what is the correct order of the protocol stack that is used to prepare the request for transmission?

-HTTP, TCP, IP, ETHERNET -1. HTTP governs the way that a web server and client interact. 2. TCP manages individual conversations between web servers and clients. 3. IP is responsible for delivery across the best path to the destination. 4. Ethernet takes the packet from IP and formats it for transmission.

Which three basic parts are common to all frame types supported by the data link layer? (Choose three.)

-Header -Data -Trailer

Scalability

-How well a system can scale up, or adapt to the increased demands of growth -A scalable network expands quickly to support new users and applications. It does this without degrading the performance of services that are being accessed by existing users. The figure shows how a new network is easily added to an existing network. These networks are scalable because the designers follow accepted standards and protocols. This lets software and hardware vendors focus on improving products and services without having to design a new set of rules for operating within the network.

Protocol Interaction

-Hypertext Transfer Protocol (HTTP) This protocol governs the way a web server and a web client interact. HTTP defines the content and formatting of the requests and responses that are exchanged between the client and server. Both the client and the web server software implement HTTP as part of the application. HTTP relies on other protocols to govern how the messages are transported between the client and server. -Transmission Control Protocol (TCP) This protocol manages the individual conversations. TCP is responsible for guaranteeing the reliable delivery of the information and managing flow control between the end devices. -Internet Protocol (IP) This protocol is responsible for delivering messages from the sender to the receiver. IP is used by routers to forward the messages across multiple networks. -Ethernet This protocol is responsible for the delivery of messages from one NIC to another NIC on the same Ethernet Local Area Network (LAN).

Which two protocols function at the internet layer? (Choose two.)

-ICMP -IP -ICMP and IP both function at the internet layer, whereas PPP is a network access layer protocol, and POP and BOOTP are application layer protocols.

Which protocols provide feedback from the destination host to the source host regarding errors in packet delivery? (Choose two.)

-ICMPv4 -ICMPv6

Which three acronyms/initialisms represent standards organizations? (Choose three.)

-IETF -IANA -IEEE -TCP/IP is a protocol stack that contains a lot of other protocols such as HTTP, FTP, and DNS. The TCP/IP protocol stack is required to be used when communicating on the Internet. A MAC address is an address that is burned into an Ethernet network card. OSI is the 7 layer model that is used to explain how networking works.

Binary Number System

-IPv4 = 32 bits in length -Binary is a numbering system that consists of the numbers 0 and 1 called bits. In contrast, the decimal numbering system consists of 10 digits consisting of the numbers 0 - 9. Binary is important for us to understand because hosts, servers, and network devices use binary addressing, specifically, binary IPv4 addresses, to identify each other. You must know binary addressing and how to convert between binary and dotted decimal IPv4 addresses.

Hexadecimal Number System

-IPv6 = 128 bits in length -Just as decimal is a base ten number system, hexadecimal is a base sixteen system. The base sixteen number system uses the numbers 0 to 9 and the letters A to F. The hexadecimal numbering system is used in networking to represent IPv6 addresses and Ethernet MAC addresses. IPv6 addresses are 128 bits in length and every 4 bits is represented by a single hexadecimal digit; for a total of 32 hexadecimal values. To convert hexadecimal to decimal, you must first convert the hexadecimal to binary, then convert the binary to decimal. To convert decimal to hexadecimal, you must also first convert the decimal to binary.

IPv6 (Internet Protocol version 6)

-IPv6 addresses are 128 bits in length and written as a string of hexadecimal values. Every four bits is represented by a single hexadecimal digit; for a total of 32 hexadecimal values. Groups of four hexadecimal digits are separated by a colon (:) . IPv6 addresses are not case-sensitive and can be written in either lowercase or uppercase.

What is done to an IP packet before it is transmitted over the physical medium?

-IT IS ENCAPSULATED IN A LAYER 2 FRAME -When messages are sent on a network, the encapsulation process works from the top of the OSI or TCP/IP model to the bottom. At each layer of the model, the upper layer information is encapsulated into the data field of the next protocol. For example, before an IP packet can be sent, it is encapsulated in a data link frame at Layer 2 so that it can be sent over the physical medium.

What are two benefits of using a layered network model? (Choose two.)

-IT PREVENTS TECHNOLOGY IN ONE LAYER FROM AFFECTING OTHER LAYERS. -IT ASSISTS IN PROTOCOL DESIGN -Some vendors have developed their own reference models and protocols. Today, if a device is to communicate on the Internet, the device must use the TCP/IP model. The benefits of using a layered model are as follows: -Assists in protocol design -Fosters competition between vendors -prevents a technology that functions at one layer from affecting any other layer -Provides a common language for describing network functionality -Helps in visualizing the interaction between each layer and protocols between each layer

Logical Topology Diagrams

-Identify devices, ports, and addressing scheme. -Identifies the physical connections and how end devices and intermediary devices (i.e, routers, switches, and wireless access points) are interconnected. The topology may also include specific device location such as room number and location on the equipment rack. Physical topologies are usually point-to-point or star. -The data link layer "sees" the logical topology of a network when controlling data access to the media. It is the logical topology that influences the type of network framing and media access control used.

Physical topology diagrams

-Identify the physical location of intermediary devices and cable installation. -Identifies the physical connections and how end devices and intermediary devices (i.e, routers, switches, and wireless access points) are interconnected. The topology may also include specific device location such as room number and location on the equipment rack. Physical topologies are usually point-to-point or star.

Alter the Running Configuration

-If changes made to the running configuration do not have the desired effect and the running-config file has not yet been saved, you can restore the device to its previous configuration by removing the changed commands individually or reload the device using the reload privileged EXEC mode command to restore the startup-config. -The downside to using the reload command to remove an unsaved running configuration is the brief amount of time the device will be offline, causing network downtime. -When a reload is initiated, the IOS will detect that the running config has changes that were not saved to the startup configuration. A prompt will appear to ask whether to save the changes. To discard the changes, enter n or no. -Alternatively, if undesired changes were saved to the startup config, it may be necessary to clear all the configurations. This requires erasing the startup config and restarting the device. The startup config is removed by using the erase startup-config privileged EXEC mode command. After the command is issued, the switch will prompt you for confirmation. Press Enter to accept. -After removing the startup config from NVRAM, reload the device to remove the current running config file from RAM. On reload, a switch will load the default startup config that originally shipped with the device.

Controlled Access

-In a controlled-based multiaccess network, each node has its own time to use the medium. These deterministic types of legacy networks are inefficient because a device must wait its turn to access the medium. Examples of multiaccess networks that use controlled access include the following: -Legacy Token Ring -Legacy ARCNET **Note: Today, Ethernet networks operate in full-duplex and do not require an access method

Node

-In computer networks, a node is a device that can receive, create, store, or forward data along a communications path. A node can be either an end device such as a laptop or mobile phone, or an intermediary device such as an Ethernet switch. -A source and destination node may be indirectly connected to each other over some geographical distance using multiple intermediary devices. However, the use of physical devices in the network does not affect the logical topology, as illustrated in the figure. In the figure, adding intermediary physical connections may not change the logical topology. The logical point-to-point connection is the same.

Contention-Based Access

-In contention-based multiaccess networks, all nodes are operating in half-duplex, competing for the use of the medium. However, only one device can send at a time. Therefore, there is a process if more than one device transmits at the same time. Examples of contention-based access methods include the following: -Carrier sense multiple access with collision detection (CSMA/CD) used on legacy bus-topology Ethernet LANs -Carrier sense multiple access with collision avoidance (CSMA/CA) used on Wireless LANs **Note: Today, Ethernet networks operate in full-duplex and do not require an access method

Devices on the Same Network

-In this example we have a client computer, PC1, communicating with an FTP server on the same IP network. -Source IPv4 address - The IPv4 address of the sending device, the client computer PC1: 192.168.1.110. -Destination IPv4 address - The IPv4 address of the receiving device, FTP server: 192.168.1.9. Notice in the figure that the network portion of both the source IPv4 address and destination IPv4 address are on the same network. -Notice in the figure that the network portion of the source IPv4 address and the network portion of the destination IPv4 address are the same and therefore; the source and destination are on the same network.

Which organization defines standards for the network access layer (i.e., the OSI physical and data link layers)?

-Institute of Electrical and Electronics Engineers (IEEE) -International Telecommunication Union (ITU) -International Organization for Standardization (ISO) -American National Standards Institute (ANSI)

Standards organizations involved with the development and support of TCP/IP and include IANA and ICANN.

-Internet Corporation for Assigned Names and Numbers (ICANN) Based in the United States, ICANN coordinates IP address allocation, the management of domain names, and assignment of other information used in TCP/IP protocols. -Internet Assigned Numbers Authority (IANA) Responsible for overseeing and managing IP address allocation, domain name management, and protocol identifiers for ICANN

Internet Layer

-Internet Protocol -Messaging -Routing Protocols -responsible for addressing, packaging, and routing messages on the Internet

Internet Standards

-Internet Society (ISOC) Responsible for promoting the open development and evolution of internet use throughout the world. -Internet Architecture Board (IAB) Responsible for the overall management and development of internet standards. -Internet Engineering Task Force (IETF) Develops, updates, and maintains internet and TCP/IP technologies. This includes the process and documents for developing new protocols and updating existing protocols, which are known as Request for Comments (RFC) documents. -Internet Research Task Force (IRTF) Focused on long-term research related to the internet and TCP/IP protocols such as Anti-Spam Research Group (ASRG), Crypto Forum Research Group (CFRG), and Peer-to-Peer Research Group (P2PRG) __________________________________________________ -Various organizations have different responsibilities for promoting and creating standards for the internet and TCP/IP protocol. -The figure displays standards organizations involved with the development and support of the internet.

Which two statements describe the services provided by the data link layer? (Choose two.)

-It manages the access of frames to the network media -It packages various Layer 3 PDUs into a frame format that is compatible with the network interface

Hexadecimal & IPv6 Addresses

-Just as decimal is a base ten number system, hexadecimal is a base sixteen system. The base sixteen number system uses the digits 0 to 9 and the letters A to F. The figure shows the equivalent decimal and hexadecimal values for binary 0000 to 1111. -Binary and hexadecimal work well together because it is easier to express a value as a single hexadecimal digit than as four binary bits. -The hexadecimal numbering system is used in networking to represent IP Version 6 addresses and Ethernet MAC addresses. -IPv6 addresses are 128 bits in length and every 4 bits is represented by a single hexadecimal digit; for a total of 32 hexadecimal values. IPv6 addresses are not case-sensitive and can be written in either lowercase or uppercase. -the preferred format for writing an IPv6 address is x:x:x:x:x:x:x:x, with each "x" consisting of four hexadecimal values. When referring to 8 bits of an IPv4 address we use the term octet. In IPv6, a hextet is the unofficial term used to refer to a segment of 16 bits or four hexadecimal values. Each "x" is a single hextet, 16 bits, or four hexadecimal digits.

Lucent Connector (LC) Simplex Connectors

-LC simplex connectors are a smaller version of the SC connector. These are sometimes called little or local connectors and are quickly growing in popularity due to their smaller size. -Until recently, light could only travel in one direction over optical fiber. Two fibers were required to support the full duplex operation. Therefore, fiber-optic patch cables bundle together two optical fiber cables and terminate them with a pair of standard, single-fiber connectors. Some fiber connectors accept both the transmitting and receiving fibers in a single connector known as a duplex connector, as shown in the Duplex Multimode LC Connector in the figure. BX standards such as 100BASE-BX use different wavelengths for sending and receiving over a single fiber.

Signaling [Fiber Optic Cable]

-Light Pulses Over Fiber-Optic Cable -Optical fiber cable transmits data over longer distances and at higher bandwidths than any other networking media. Fiber-optic cable can transmit signals with less attenuation than copper wire and is completely immune to EMI and RFI. Optical fiber is a flexible, but extremely thin, transparent strand of very pure glass, not much bigger than a human hair. Bits are encoded on the fiber as light impulses. Fiber-optic cabling is now being used in four types of industry: enterprise networks, FTTH, long-haul networks, and submarine cable networks. There are four types of fiber-optic connectors: ST, SC, LC, and duplex multimode LC. Fiber-optic patch cords include SC-SC multimode, LC-LC single-mode, ST-LC multimode, and SC-ST single-mode. In most enterprise environments, optical fiber is primarily used as backbone cabling for high-traffic point-to-point connections between data distribution facilities and for the interconnection of buildings in multi-building campuses.

The IEEE 802 LAN/MAN data link layer consists of which two sublayers? (Choose two.)

-Logical Link Control -Media Access Control

Which two statements describe features or functions of the logical link control sublayer in Ethernet standards? (Choose two.)

-Logical link control is implemented in software. -The data link layer uses LLC to communicate with the upper layers of the protocol suite.

Multimode Fiber

-MMF consists of a larger core and uses LED emitters to send light pulses. Specifically, light from an LED enters the multimode fiber at different angles as shown in the figure. Popular in LANs because they can be powered by low-cost LEDs. It provides bandwidth up to 10 Gb/s over link lengths of up to 550 meters. -Allows multiple paths of light. -One of the highlighted differences between MMF and SMF is the amount of dispersion. Dispersion refers to the spreading out of a light pulse over time. Increased dispersion means increased loss of signal strength. MMF has a greater dispersion than SMF. That is why MMF can only travel up to 500 meters before signal loss.

Which type of communication will send a message to a group of host destinations simultaneously?

-MULTICAST -Multicast is a one-to-many communication where the message is delivered to a specific group of hosts. Broadcast communication is a one-to-all communication. A unicast communication is a one-to-one communication. Anycast is an IPv6 term and is the sending of data in a one-to-nearest communication.

The media access control method used depends on which two criteria?

-Media sharing -Topology

All communication methods have the following 3 elements in common........

-Message Source (sender) Message sources are people, or electronic devices, that need to send a message to other individuals or devices. -Message Destination (receiver) The destination receives the message & interprets it. -Channel - This consists of the media that provides the pathway over which the message travels from source to destination.

Network Protocol Requirements

-Message encoding -Message formatting and encapsulation -Message size -Message timing -Message delivery options

Signaling [Wireless Media]

-Microwave Signals Over Wireless -Wireless media carry electromagnetic signals that represent the binary digits of data communications using radio or microwave frequencies. Wireless does have some limitations, including: coverage area, interference, security, and the problems that occur with any shared medium. Wireless standards include the following: Wi-Fi (IEEE 802.11), Bluetooth (IEEE 802.15), WiMAX (IEEE 802.16), and Zigbee (IEEE 802.15.4). Wireless LAN (WLAN) requires a wireless AP and wireless NIC adapters.

Manual IP Address Configuration for End Devices

-Much like you need your friends' telephone numbers to text or call them, end devices in your network need an IP address so that they can communicate with other devices on your network. In this topic, you will implement basic connectivity by configuring IP addressing on switches and PCs. -IPv4 address information can be entered into end devices manually, or automatically using Dynamic Host Configuration Protocol (DHCP). -To manually configure an IPv4 address on a Windows host, open the Control Panel > Network Sharing Center > Change adapter settings and choose the adapter. Next right-click and select Properties to display the Local Area Connection Properties, as shown in the figure. -Highlight Internet Protocol Version 4 (TCP/IPv4) and click Properties to open the Internet Protocol Version 4 (TCP/IPv4) Properties window, shown in the figure. Configure the IPv4 address and subnet mask information, and default gateway. **Note: IPv6 addressing and configuration options are similar to IPv4. **Note: The DNS server addresses are the IPv4 and IPv6 addresses of the Domain Name System (DNS) servers, which are used to translate IP addresses to domain names, such as www.cisco.com.

Various types of protocols that are needed to enable communications across one or more networks.

-Network Communications Protocols Protocols enable two or more devices to communicate over one or more networks. The Ethernet family of technologies involves a variety of protocols such as IP, Transmission Control Protocol (TCP), HyperText Transfer Protocol (HTTP), and many more. -Network Security Protocols Protocols secure data to provide authentication, data integrity, and data encryption. Examples of secure protocols include Secure Shell (SSH), Secure Sockets Layer (SSL), and Transport Layer Security (TLS). -Routing Protocols Protocols enable routers to exchange route information, compare path information, and then to select the best path to the destination network. Examples of routing protocols include Open Shortest Path First (OSPF) and Border Gateway Protocol (BGP). -Service Discovery Protocols Protocols are used for the automatic detection of devices or services. Examples of service discovery protocols include Dynamic Host Configuration Protocol (DHCP) which discovers services for IP address allocation, and Domain Name System (DNS) which is used to perform name-to-IP address translation.

Which of the following statements are true regarding network layer and data link layer addresses? (Choose three.)

-Network layer addresses are logical and data link addresses are expressed as 12 hexadecimal digits. -Data link layer addresses are physical and network layer addresses are logical -Network layer addresses are either 32 or 128 bits in length.

Intranets

-Often used to refer to a private connection of LANs and WANs that belongs to an organization. -An intranet is designed to be accessible only by the organization's members, employees, or others with authorization. -Private company networks that allow employees to easily access, share, and publish information using internet software

TCP/IP Protocol Suite (Transmission Control Protocol/Internet Protocol)

-Open Standard Protocol Suite This means it is freely available to the public and can be used by any vendor on their hardware or in their software. -Standards-Based Protocol Suite This means it has been endorsed by the networking industry and approved by a standard organization. This ensures that products from different manufacturers can interoperate successfully. Layer Name / Protocol Stack Application / HTTP Transport / TCP Internet / IP Network Access / Ethernet **Note: TCP/IP protocols are used for each layer to send packets except for Network Access layer, Ethernet or WLAN or cellular service can be used for Network Access.

Electronic and Communications Standards

-Other standards organizations have responsibilities for promoting and creating the electronic and communication standards used to deliver the IP packets as electronic signals over a wired or wireless medium. These standard organizations include the following: -Institute of Electrical and Electronics Engineers (IEEE, pronounced "I-triple-E") - Organization of electrical engineering and electronics dedicated to advancing technological innovation and creating standards in a wide area of industries including power and energy, healthcare, telecommunications, and networking. Important IEEE networking standards include 802.3 Ethernet and 802.11 WLAN standard. Search the internet for other IEEE network standards. -Electronic Industries Alliance (EIA) - Organization is best known for its standards relating to electrical wiring, connectors, and the 19-inch racks used to mount networking equipment. -Telecommunications Industry Association (TIA) - Organization responsible for developing communication standards in a variety of areas including radio equipment, cellular towers, Voice over IP (VoIP) devices, satellite communications, and more. -International Telecommunications Union-Telecommunication Standardization Sector (ITU-T) - One of the largest and oldest communication standards organizations. The ITU-T defines standards for video compression, Internet Protocol Television (IPTV), and broadband communications, such as a digital subscriber line (DSL).

What is the general term that is used to describe a piece of data at any layer of a networking model?

-PROTOCOL DATA UNIT -The term protocol data unit (PDU) is used to describe a piece of data at any layer of a networking model. A packet is the PDU at the network layer. A frame is the data link layer PDU. A segment is the PDU at the transport layer.

What is the purpose of protocols in data communications?

-PROVIDING THE RULES REQUIRED FOR A SPECIFIC TYPE OF COMMUNICATION TO OCCUR -Protocols provide rules that define how a message is transmitted across a network. Implementation requirements such as electronic and bandwidth details for data communication are specified by standards. Operating systems are not specified by protocols, but will implement protocols. Protocols determine how and when to send a message but they do not control the contents of a message.

The TCP/IP Protocol Model

-Referred to as the internet model. This type of model closely matches the structure of a particular protocol suite. -TCP/IP is also used as a reference model. -The definitions of the standard and the TCP/IP protocols are discussed in a public forum and defined in a publicly available set of IETF RFCs. An RFC is authored by networking engineers and sent to other IETF members for comments. 4 - Application Represents data to the user, plus encoding and dialog control. 3 - Transport Supports communication between various devices across diverse networks. 2 - Internet Determines the best path through the network. 1 - Network Access Controls the hardware devices and media that make up the network.

Which services are provided by the internet layer of the TCP/IP protocol suite? (Choose three.)

-Routing Protocols -Messaging -Internet Protocol

Subscriber Connector (SC) Connectors

-SC connectors are sometimes referred to as square connector or standard connector. They are a widely-adopted LAN and WAN connector that uses a push-pull mechanism to ensure positive insertion. This connector type is used with multimode and single-mode fiber. -Until recently, light could only travel in one direction over optical fiber. Two fibers were required to support the full duplex operation. Therefore, fiber-optic patch cables bundle together two optical fiber cables and terminate them with a pair of standard, single-fiber connectors. Some fiber connectors accept both the transmitting and receiving fibers in a single connector known as a duplex connector, as shown in the Duplex Multimode LC Connector in the figure. BX standards such as 100BASE-BX use different wavelengths for sending and receiving over a single fiber.

Single-Mode Fiber

-SMF consists of a very small core and uses expensive laser technology to send a single ray of light, as shown in the figure. SMF is popular in long-distance situations spanning hundreds of kilometers, such as those required in long haul telephony and cable TV applications. -Produces single straight path of light. -One of the highlighted differences between MMF and SMF is the amount of dispersion. Dispersion refers to the spreading out of a light pulse over time. Increased dispersion means increased loss of signal strength. MMF has a greater dispersion than SMF. That is why MMF can only travel up to 500 meters before signal loss.

Straight-Tip (ST) Connectors

-ST connectors were one of the first connector types used. The connector locks securely with a "Twist-on/twist-off" bayonet-style mechanism. -Until recently, light could only travel in one direction over optical fiber. Two fibers were required to support the full duplex operation. Therefore, fiber-optic patch cables bundle together two optical fiber cables and terminate them with a pair of standard, single-fiber connectors. Some fiber connectors accept both the transmitting and receiving fibers in a single connector known as a duplex connector, as shown in the Duplex Multimode LC Connector in the figure. BX standards such as 100BASE-BX use different wavelengths for sending and receiving over a single fiber.

Which two Internet connection options do not require that physical cables be run to the building? (Choose two.)

-Satellite -Cellular

OSI and TCP/IP Model Comparison

-See Photo Attached! -The key similarities are in the transport and network layers; However, the 2 models differ in how they relate to the layers above and below each layer. -The protocols that make up the TCP/IP protocol suite can also be described in terms of the OSI reference model. In the OSI model, the network access layer and the application layer of the TCP/IP model are further divided to describe discrete functions that must occur at these layers. -At the network access layer, the TCP/IP protocol suite does not specify which protocols to use when transmitting over a physical medium; it only describes the handoff from the internet layer to the physical network protocols. OSI Layers 1 and 2 discuss the necessary procedures to access the media and the physical means to send data over a network.

Shielded twisted-pair (STP)

-Shielded twisted-pair (STP) provides better noise protection than UTP cabling. However, compared to UTP cable, STP cable is significantly more expensive and difficult to install. Like UTP cable, STP uses an RJ-45 connector. -STP cables combine the techniques of shielding to counter EMI and RFI, and wire twisting to counter crosstalk. To gain the full benefit of the shielding, STP cables are terminated with special shielded STP data connectors. If the cable is improperly grounded, the shield may act as an antenna and pick up unwanted signals. The STP cable shown uses four pairs of wires, each wrapped in a foil shield, which are then wrapped in an overall metallic braid or foil. 1. Outer Jacket 2. Braided or Foil Shield 3. Foil Shields 4. Twisted Pairs

In computer communication, what is the purpose of message encoding?

-TO CONVERT INFO TO THE APPROPRIATE FORM FOR TRANSMISSION. -Before a message is sent across a network it must first be encoded. Encoding is the process of converting the data message into another format suitable for transmission across the physical medium. Each bit of the message is encoded into a pattern of sounds, light waves, or electrical impulses depending on the network media over which the bits are transmitted. The destination host receives and decodes the signals in order to interpret the message.

Which layer of the OSI model defines services to segment and reassemble data for individual communications between end devices?

-TRANSPORT -The OSI model consists of seven layers: application, presentation, session, transport, network, data link, and physical. The transport layer defines services to segment, transfer, and reassemble the data for individual communications between the end devices.

IPv4

-The Internet Protocol version 4 is the dominant protocol for routing traffic on the Internet, specifying "to" and "from" addresses using a dotted decimal such as "122.45.255.0". -The structure of an IPv4 address is called dotted decimal notation and is represented by four decimal numbers between 0 and 255. IPv4 addresses are assigned to individual devices connected to a network. -With the IPv4 address, a subnet mask is also necessary. An IPv4 subnet mask is a 32-bit value that differentiates the network portion of the address from the host portion. Coupled with the IPv4 address, the subnet mask determines to which subnet the device is a member. -The example in the figure displays the IPv4 address (192.168.1.10), subnet mask (255.255.255.0), and default gateway (192.168.1.1) assigned to a host. The default gateway address is the IP address of the router that the host will use to access remote networks, including the internet.

Fault Tolerance

-The ability for a system to respond to unexpected failures or system crashes as the backup system immediately and automatically takes over with no loss of service. -A fault tolerant network is one that limits the number of affected devices during a failure. It is built to allow quick recovery when such a failure occurs. These networks depend on multiple paths between the source and destination of a message. If one path fails, the messages are instantly sent over a different link. Having multiple paths to a destination is known as redundancy. Implementing a packet-switched network is one way that reliable networks provide redundancy. Packet switching splits traffic into packets that are routed over a shared network. A single message, such as an email or a video stream, is broken into multiple message blocks, called packets. Each packet has the necessary addressing information of the source and destination of the message. The routers within the network switch the packets based on the condition of the network at that moment. This means that all the packets in a single message could take very different paths to the same destination. In the figure, the user is unaware and unaffected by the router that is dynamically changing the route when a link fails.

Network Architecture

-The design of a computer network; includes both physical and logical design. -Networks also support a wide range of applications and services. They must operate over many different types of cables and devices, which make up the physical infrastructure. The term network architecture, in this context, refers to the technologies that support the infrastructure and the programmed services and rules, or protocols, that move data across the network. -As networks evolve, we have learned that there are four basic characteristics that network architects must address to meet user expectations: Fault Tolerance Scalability Quality of Service (QoS) Security

Which two statements are true regarding the user EXEC mode? (Choose two.)

-The device prompt for this mode ends with the ">" symbol. -Only some aspects of the router configuration can be viewed.

A network administrator is connecting two modern switches using a straight-through cable. The switches are new and have never been configured. Which three statements are correct about the final result of the connection? (Choose three.)

-The link between the switches will work at the fastest speed that is supported by both switches. -The link between switches will work as full-duplex. -The auto-MDIX feature will configure the interfaces eliminating the need for a crossover cable.

Signaling

-The physical layer must generate the electrical, optical, or wireless signals that represent the "1" and "0" on the media. The way that bits are represented is called the signaling method. The physical layer standards must define what type of signal represents a "1" and what type of signal represents a "0". This can be as simple as a change in the level of an electrical signal or optical pulse. For example, a long pulse might represent a 1 whereas a short pulse might represent a 0. -This is similar to the signaling method used in Morse code, which may use a series of on-off tones, lights, or clicks to send text over telephone wires or between ships at sea.

Physical Components. [Physical Layer]

-The physical layer standards address three functional areas: Physical Components Encoding Signaling -The physical components are the electronic hardware devices, media, and other connectors that transmit the signals that represent the bits. Hardware components such as NICs, interfaces and connectors, cable materials, and cable designs are all specified in standards associated with the physical layer. The various ports and interfaces on a Cisco 1941 router are also examples of physical components with specific connectors and pinouts resulting from standards. -Purpose of the Physical Layer Before any network communications can occur, a physical connection to a local network must be established. A physical connection can be a wired connection using a cable or a wireless connection using radio waves. Network Interface Cards (NICs) connect a device to the network. Ethernet NICs are used for a wired connection, whereas WLAN (Wireless Local Area Network) NICs are used for wireless. The OSI physical layer provides the means to transport the bits that make up a data link layer frame across the network media. This layer accepts a complete frame from the data link layer and encodes it as a series of signals that are transmitted onto the local media. The encoded bits that comprise a frame are received by either an end device or an intermediary device. -Physical Layer Characteristics The physical layer consists of electronic circuitry, media, and connectors developed by engineers. The physical layer standards address three functional areas: physical components, encoding, and signaling. Bandwidth is the capacity at which a medium can carry data. Digital bandwidth measures the amount of data that can flow from one place to another in a given amount of time. Throughput is the measure of the transfer of bits across the media over a given period of time and is usually lower than bandwidth. Latency refers to the amount of time, including delays, for data to travel from one given point to another. Goodput is the measure of usable data transferred over a given period of time. The physical layer produces the representation and groupings of bits for each type of media as follows: -Copper cable - The signals are patterns of electrical pulses. -Fiber-optic cable - The signals are patterns of light. -Wireless - The signals are patterns of microwave transmissions.

Segmentation Messages

-The process of dividing a stream of data into smaller units for transmissions over the network. -Segmentation is necessary because data networks use the TCP/IP protocol suite send data in individual IP packets. Each packet is sent separately, similar to sending a long letter as a series of individual postcards. Packets containing segments for the same destination can be sent over different paths. This leads to segmenting messages having two primary benefits: -Increases speed - Because a large data stream is segmented into packets, large amounts of data can be sent over the network without tying up a communications link. This allows many different conversations to be interleaved on the network called multiplexing. Increases efficiency -If a single segment is fails to reach its destination due to a failure in the network or network congestion, only that segment needs to be retransmitted instead of resending the entire data stream.

To restore a configuration file to a device:

-The text file created can be used as a record of how the device is currently implemented. The file could require editing before being used to restore a saved configuration to a device. -Step 1. Enter global configuration mode on the device. -Step 2. Copy and paste the text file into the terminal window connected to the switch. -The text in the file will be applied as commands in the CLI and become the running configuration on the device. This is a convenient method of manually configuring a device.

Encoding

-The transition occurs at the middle of each bit period. -Encoding or line encoding is a method of converting a stream of data bits into a predefined "code". Codes are groupings of bits used to provide a predictable pattern that can be recognized by both the sender and the receiver. In other words, encoding is the method or pattern used to represent digital information. This is similar to how Morse code encodes a message using a series of dots and dashes. -For example, Manchester encoding represents a 0 bit by a high to low voltage transition, and a 1 bit is represented as a low to high voltage transition. An example of Manchester encoding is illustrated in the figure. The transition occurs at the middle of each bit period. This type of encoding is used in 10 Mbps Ethernet. Faster data rates require more complex encoding. Manchester encoding is used in older Ethernet standards such as 10BASE-T. Ethernet 100BASE-TX uses 4B/5B encoding and 1000BASE-T uses 8B/10B encoding.

Fiber versus Copper

-There are many advantages to using fiber-optic cable compared to copper cables. The table highlights some of these differences. -At present, in most enterprise environments, optical fiber is primarily used as backbone cabling for high-traffic, point-to-point connections between data distribution facilities. It is also used for the interconnection of buildings in multi-building campuses. Because fiber-optic cables do not conduct electricity and have a low signal loss, they are well suited for these uses.

Denial of Service Attack

-These attacks slow or crash applications and processes on a network device. -A cyber attack in which an attacker sends a flood of data packets to the target computer, with the aim of overloading its resources

What are two functions of end devices on a network? (Choose two.)

-They originate the data that flows through the network. -They are the interface between humans and the communication network.

Data Interception and theft

-This attack captures private information from an organization's network. -The unauthorized taking or interception of computer-based information. Data theft is the act of stealing computer-based information from an unknowing victim with the intent of compromising privacy or obtaining confidential information.

Point-to-Point WAN Topology

-This is the simplest and most common WAN topology. It consists of a permanent link between two endpoints. -Physical point-to-point topologies directly connect two nodes, as shown in the figure. In this arrangement, two nodes do not have to share the media with other hosts. Additionally, when using a serial communications protocol such as Point-to-Point Protocol (PPP), a node does not have to make any determination about whether an incoming frame is destined for it or another node. Therefore, the logical data link protocols can be very simple, as all frames on the media can only travel to or from the two nodes. The node places the frames on the media at one end and those frames are taken from the media by the node at the other end of the point-to-point circuit. **Note: A point-to-point connection over Ethernet requires the device to determine if the incoming frame is destined for this node.

Switch Virtual Interface Configuration

-To access the switch remotely, an IP address and a subnet mask must be configured on the SVI. To configure an SVI on a switch, use the interface vlan 1 global configuration command. Vlan 1 is not an actual physical interface but a virtual one. -Next assign an IPv4 address using the ip address ip-address subnet-mask interface configuration command. Finally, enable the virtual interface using the no shutdown interface configuration command. After these commands are configured, the switch has all the IPv4 elements ready for communication over the network. **Note: Similar to a Windows hosts, switches configured with an IPv4 address will typically also need to have a default gateway assigned. This can be done using the ip default-gateway ip-address global configuration command. The ip-address parameter would be the IPv4 address of the local router on the network, as shown in the example. However, in this module you will only be configuring a network with switches and hosts. Routers will be introduced later.

Configuration Mode and SubConfiguration Modes

-To configure the device, the user must enter global configuration mode, which is commonly called global config mode. -From global config mode, CLI configuration changes are made that affect the operation of the device as a whole. Global configuration mode is identified by a prompt that ends with (config)# after the device name, such as Switch(config)#. -Global configuration mode is accessed before other specific configuration modes. From global config mode, the user can enter different subconfiguration modes. Each of these modes allows the configuration of a particular part or function of the IOS device. Two common subconfiguration modes include: -Line Configuration Mode - Used to configure console, SSH, Telnet, or AUX access. -Interface Configuration Mode - Used to configure a switch port or router network interface. -When the CLI is used, the mode is identified by the command-line prompt that is unique to that mode. By default, every prompt begins with the device name. Following the name, the remainder of the prompt indicates the mode. For example, the default prompt for line configuration mode is Switch(config-line)# and the default prompt for interface configuration mode is Switch(config-if)#.

RJ-45 UTP Plugs

-UTP cable is usually terminated with an RJ-45 connector. As shown in the figure, the RJ-45 connector is the male component, crimped at the end of the cable.

Full-Duplex Communications

-Understanding duplex communication is important when discussing LAN topologies because it refers to the direction of data transmission between two devices. There are two common modes of duplex. -Both devices can simultaneously transmit and receive on the shared media. The data link layer assumes that the media is available for transmission for both nodes at any time. Ethernet switches operate in full-duplex mode by default, but they can operate in half-duplex if connecting to a device such as an Ethernet hub. -It is important that two interconnected interfaces, such as a host NIC and an interface on an Ethernet switch, operate using the same duplex mode. Otherwise, there will be a duplex mismatch creating inefficiency and latency on the link.

Half-Duplex Communication

-Understanding duplex communication is important when discussing LAN topologies because it refers to the direction of data transmission between two devices. There are two common modes of duplex. -Both devices can transmit and receive on the media but cannot do so simultaneously. WLANs and legacy bus topologies with Ethernet hubs use the half-duplex mode. Half-duplex allows only one device to send or receive at a time on the shared medium.

Message Delivery Options

-Unicast - Information is being transmitted to a single end device. -Multicast - Information is being transmitted to a one or more end devices. -Broadcast - Inform **Note: Nodes are typically represented as a circle.

Unshielded twisted-pair (UTP)

-Unshielded twisted-pair (UTP) cabling is the most common networking media. UTP cabling, terminated with RJ-45 connectors, is used for interconnecting network hosts with intermediary networking devices, such as switches and routers. -In LANs, UTP cable consists of four pairs of color-coded wires. As seen in the figure, the color codes identify the individual pairs and wires and aid in cable termination. 1. The outer jacket protects the copper wires from physical damage. 2. Twisted-pairs protect the signal from interference. 3. Color-coded plastic insulation electrically isolates wires from each other and identifies each pair.

Powerline Networking

-Uses existing electrical wiring to connect devices -Using a standard powerline adapter, devices can connect to the LAN wherever there is an electrical outlet. No data cables need to be installed, and there is little to no additional electricity used. Using the same wiring that delivers electricity, powerline networking sends information by sending data on certain frequencies. -Powerline networking is especially useful when wireless access points cannot reach all the devices in the home. -Powerline networking is not a substitute for dedicated cabling in data networks. However, it is an alternative when data network cables or wireless communications are not possible or effective.

Test the Interface Assignment

-Using the CLI, you will verify the interfaces and the addresses of the switches and routers in your network. -In the same way that you use commands and utilities like ipconfig to verify the network configuration of a PC host, you also use commands to verify the interfaces and address settings of intermediary devices like switches and routers. -show ip interface brief command is useful for verifying the condition of the switch interfaces.

What are two actions performed by a Cisco switch? (Choose two.)

-Using the source MAC addresses of frames to build and maintain a MAC address table -Utilizing the MAC address table to forward frames via the destination MAC address

Navigate Between IOS Modes

-Various commands are used to move in and out of command prompts. To move from user EXEC mode to privileged EXEC mode, use the enable command. Use the disable privileged EXEC mode command to return to user EXEC mode. **Note: Privileged EXEC mode is sometimes called enable mode. -To move in and out of global configuration mode, use the configure terminal privileged EXEC mode command. To return to the privileged EXEC mode, enter the exit global config mode command. -There are many different subconfiguration modes. For example, to enter line subconfiguration mode, you use the line command followed by the management line type and number you wish to access. Use the exit command to exit a subconfiguration mode and return to global configuration mode. -To move from any subconfiguration mode of the global configuration mode to the mode one step above it in the hierarchy of modes, enter the exit command. -To move from any subconfiguration mode to the privileged EXEC mode, enter the end command or enter the key combination Ctrl+Z. -You can also move directly from one subconfiguration mode to another. Notice how after selecting an interface, the command prompt changes from (config-line)# to (config-if)#.

WANs (Wide Area Networks)

-WANs interconnect LANs over wide geographical areas such as between cities, states, provinces, countries, or continents. -WANs are usually administered by multiple service providers. -WANs typically provide slower speed links between LANs. --The figure shows two branch LANs connected via a WAN link. -Managed by service providers (SPs) or Internet Service Providers.

Role of the Data Link Layer Addresses: Different IP Networks

-When the sender and receiver of the IP packet are on different networks, the Ethernet data link frame cannot be sent directly to the destination host because the host is not directly reachable in the network of the sender. The Ethernet frame must be sent to another device known as the router or default gateway. In our example, the default gateway is R1. R1 has an Ethernet data link address that is on the same network as PC1. This allows PC1 to reach the router directly. -Source MAC address The Ethernet MAC address of the sending device, PC1. The MAC address of the Ethernet interface of PC1 is AA-AA-AA-AA-AA-AA. -Destination MAC address When the receiving device, the destination IP address, is on a different network from the sending device, the sending device uses the Ethernet MAC address of the default gateway or router. In this example, the destination MAC address is the MAC address of the R1 Ethernet interface, 11-11-11-11-11-11. This is the interface that is attached to the same network as PC1, as shown in the figure. -The Ethernet frame with the encapsulated IP packet can now be transmitted to R1. R1 forwards the packet to the destination, Web Server. This may mean that R1 forwards the packet to another router or directly to Web Server if the destination is on a network connected to R1. -It is important that the IP address of the default gateway be configured on each host on the local network. All packets to a destination on remote networks are sent to the default gateway.

Role of the Data Link Layer Addresses: Same IP Network

-When the sender and receiver of the IP packet are on the same network, the data link frame is sent directly to the receiving device. On an Ethernet network, the data link addresses are known as Ethernet Media Access Control (MAC) addresses, as highlighted in the figure. -MAC addresses are physically embedded on the Ethernet NIC. -Source MAC address - This is the data link address, or the Ethernet MAC address, of the device that sends the data link frame with the encapsulated IP packet. The MAC address of the Ethernet NIC of PC1 is AA-AA-AA-AA-AA-AA, written in hexadecimal notation. -Destination MAC address - When the receiving device is on the same network as the sending device, this is the data link address of the receiving device. In this example, the destination MAC address is the MAC address of the FTP server: CC-CC-CC-CC-CC-CC, written in hexadecimal notation. -The frame with the encapsulated IP packet can now be transmitted from PC1 directly to the FTP server.

Role of the Network Layer Addresses

-When the sender of the packet is on a different network from the receiver, the source and destination IP addresses will represent hosts on different networks. This will be indicated by the network portion of the IP address of the destination host. -Source IPv4 address - The IPv4 address of the sending device, the client computer PC1: 192.168.1.110. -Destination IPv4 address - The IPv4 address of the receiving device, the server, Web Server: 172.16.1.99. **Notice in the figure that the network portion of the source IPv4 address and destination IPv4 address are on different networks.

Command Line Interface (CLI)

-When using a CLI, the user interacts directly with the system in a text-based environment by entering commands on the keyboard at a command prompt, as shown in the example. The system executes the command, often providing textual output. The CLI requires very little overhead to operate. However, it does require that the user have knowledge of the underlying command structure that controls the system. -The CLI is less resource intense and very stable when compared to GUI. -Network devices are typically accessed through CLI. -Using the CLI may provide the network administrator with more precise control and flexibility than using the GUI.

Network Media

-Wireless, LAN, WAN -The conduit through which signals flow, can be either bounded or unbounded.

Properties of Wireless Media

-You may be taking this course using a tablet or a smart phone. This is only possible due to wireless media, which is the third way to connect to the physical layer of a network. -Wireless media carry electromagnetic signals that represent the binary digits of data communications using radio or microwave frequencies. -Wireless media provide the greatest mobility options of all media, and the number of wireless-enabled devices continues to increase. Wireless is now the primary way users connect to home and enterprise networks. These are some of the limitations of wireless: -Coverage area - Wireless data communication technologies work well in open environments. However, certain construction materials used in buildings and structures, and the local terrain, will limit the effective coverage. -Interference - Wireless is susceptible to interference and can be disrupted by such common devices as household cordless phones, some types of fluorescent lights, microwave ovens, and other wireless communications. -Security - Wireless communication coverage requires no access to a physical strand of media. Therefore, devices and users, not authorized for access to the network, can gain access to the transmission. Network security is a major component of wireless network administration. -Shared medium - WLANs operate in half-duplex, which means only one device can send or receive at a time. The wireless medium is shared amongst all wireless users. Many users accessing the WLAN simultaneously results in reduced bandwidth for each user. -Although wireless is increasing in popularity for desktop connectivity, copper and fiber are the most popular physical layer media for deployment of intermediary network devices, such as routers and switches.

Intermediary Devices

-[Wireless Router, LAN Switch, Router, Multiplayer Switch, Firewall Appliance] -Connect the individual end devices to the network -Can connect multiple individual networks to form an internetwork

In addition to the cable length, what two factors could interfere with the communication carried over UTP cables? (Choose two.)

-electromagnetic interference -crosstalk

A network administrator is measuring the transfer of bits across the company backbone for a mission critical financial application. The administrator notices that the network throughput appears lower than the bandwidth expected. Which three factors could influence the differences in throughput? (Choose three.)

-the amount of traffic that is currently crossing the network -the type of traffic that is crossing the network -the latency that is created by the number of network devices that the data is crossing

Which is a multicast MAC address?

01-00-5E-00-00-03

Refer to the exhibit. The PC is connected to the console port of the switch. All the other connections are made through FastEthernet links. Which types of UTP cables can be used to connect the devices?​

1 - rollover, 2 - straight-through, 3 - crossover

To what subnet does the IP address 10.1.100.50 belong if a subnet mask of 255.255.0.0 is used?

10.1.0.0

CISCO - CHAPTER 3

3 - Introduction - Network Protocols & Models -Explains how network protocols enable devices to access local and remote network resources.

CHAPTER 5

5 - Number Systems

CHAPTER 6

6 - Data Link Layer

The OSI Reference Model (OSI Model Layer)

7 - Application The application layer contains protocols used for process-to-process communications. 6 - Presentation The presentation layer provides for common representation of the data transferred between application layer services. 5 - Session The session layer provides services to the presentation layer to organize its dialogue and to manage data exchange. 4 - Transport The transport layer defines services to segment, transfer, and reassemble the data for individual communications between the end devices. 3 - Network The network layer provides services to exchange the individual pieces of data over the network between identified end devices. 2 - Data Link The data link layer protocols describe methods for exchanging data frames between devices over a common media 1 - Physical The physical layer protocols describe the mechanical, electrical, functional, and procedural means to activate, maintain, and de-activate physical connections for a bit transmission to and from a network device. **Note: Whereas the TCP/IP model layers are referred to only by name, the seven OSI model layers are more often referred to by number rather than by name. For instance, the physical layer is referred to as Layer 1 of the OSI model, data link layer is Layer2, and so on.

SecureCRT

A commercial SSH and Telnet client and terminal emulator by VanDyke Software

Wireless LAN

A common wireless data implementation is enabling devices to connect wirelessly via a LAN. In general, a WLAN requires the following network devices: -Wireless Access Point (AP) - These concentrate the wireless signals from users and connect to the existing copper-based network infrastructure, such as Ethernet. Home and small business wireless routers integrate the functions of a router, switch, and access point into one device, as shown in the figure. -Wireless NIC adapters - These provide wireless communication capability to network hosts. -As the technology has developed, a number of WLAN Ethernet-based standards have emerged. When purchasing wireless devices, ensure compatibility and interoperability. -The benefits of wireless data communications technologies are evident, especially the savings on costly premises wiring and the convenience of host mobility. Network administrators must develop and apply stringent security policies and processes to protect WLANs from unauthorized access and damage. -In figure: Cisco Meraki MX64W

Physical Port "Interface"

A connector or outlet on a networking device where the media connects to an end device or another networking device.

In which scenario would the use of a WISP be recommended?

A farm in a rural area without wired broadband access.

Threat Actor Attacks

A malicious person attacks user devices or network resources.

Which device performs the function of determining the path that messages should take through internetworks?

A router

Network Access Layer

Address Resolution -ARP (Address Resolution Protocol) Provides dynamic address mapping an IPv4 address and a hardware address. **Note: You may see other documentation state that ARP operates at the Internet Layer (OSI Layer 3). However, in this course we state that ARP operates at the Network Access layer (OSI Layer 2) because it's primary purpose is the discover the MAC address of the destination. A MAC address is a Layer 2 address. Data Link Protocols -Ethernet Defines the rules for wiring and signaling standards of the network access layer. -WLAN (Wireless Local Area Network) Defines the rules for wireless signaling across the 2.4 GHz and 5 GHz radio frequencies.

What OSI physical layer term describes the physical medium for microwave transmissions?

Air

Zero-day attacks, also called zero-hour attacks

An attack that occurs on the first day that a vulnerability becomes known

Contention-Based Access - CSMA/CA

Another form of CSMA that is used by IEEE 802.11 WLANs is Carrier Sense Multiple Access/Collision Avoidance (CSMA/CA). -CMSA/CA uses a method similar to CSMA/CD to detect if the media is clear. CMSA/CA uses additional techniques. In wireless environments it may not be possible for a device to detect a collision. CMSA/CA does not detect collisions but attempts to avoid them by waiting before transmitting. Each device that transmits includes the time duration that it needs for the transmission. All other wireless devices receive this information and know how long the medium will be unavailable. In the figure, if host A is receiving a wireless frame from the access point, hosts B, and C will also see the frame and how long the medium will be unavailable. -After a wireless device sends an 802.11 frame, the receiver returns an acknowledgment so that the sender knows the frame arrived. -Whether it is an Ethernet LAN using hubs, or a WLAN, contention-based systems do not scale well under heavy media use. **Note: Ethernet LANs using switches do not use a contention-based system because the switch and the host NIC operate in full-duplex mode.

Which functionality is provided by DHCP?

Automatic assignment of an IP address to each host

Which access method would be the most appropriate if you call your manager to tell him you cannot access your router in another city over the internet and he provides you with the information to access the router through a telephone connection?

Aux

Which feature describes using personal tools to access information and communicate across a business or campus network?

BYOD

How does BYOD change the way in which businesses implement networks?

BYOD provides flexibility in where and how users can access network resources.

Which of these is the name for the capacity of a medium to carry data?

Bandwidth

CISCO - CHAPTER 2

Basic Switch and End Device Configuration

Which of the following wireless standards is used for Personal Area Networks (PANs) and allows devices to communicate over distances of 1 to 100 meters?

Bluetooth

A large corporation has modified its network to allow users to access network resources from their personal laptops and smart phones. Which networking trend does this describe?

Bring Your Own Device (BYOD)

MODULE 2 CHAPTER 4

CH: 4 Physical Layer

When the store-and-forward method of switching is in use, what part of the Ethernet frame is used to perform an error check?

CRC in the trailer

What is a characteristic of UTP cabling?

Cancellation

Which media access control method is used in legacy Ethernet LANs?

Carrier sense multiple access/Collision Detection

Which feature contains options such as Public, Private, Custom and Hybrid?

Cloud Computing

Which of the following attaches antennas to wireless devices? It can also be bundled with fiber-optic cabling for two-way data transmission.

Coaxial

Which of the following terminates with BNC, N type and F type connectors?

Coaxial

Capture Configuration to a Text File

Configuration files can also be saved and archived to a text document -Step 1. Open terminal emulation software, such as PuTTY or Tera Term, that is already connected to a switch. -Step 2. Enable logging in the terminal software and assign a name and file location to save the log file. The figure displays that All session output will be captured to the file specified (i.e., MySwitchLogs). -Step 3. Execute the show running-config or show startup-config command at the privileged EXEC prompt. Text displayed in the terminal window will be placed into the chosen file. -Step 4. Disable logging in the terminal software. The figure shows how to disable logging by choosing the None session logging option.

Transport Layer

Connection-Oriented -TCP (Transmission Control Protocol) Enables reliable communication between processes running on separate hosts and provides reliable, acknowledged transmissions that confirm successful delivery. Connectionless -UDP (User Datagram Protocol) Enables a process running on one host to send packets to a process running on another host. However, UDP does not confirm successful datagram transmission.

Which access method would be most appropriate if you were in the equipment room with a new switch that needs to be configured?

Console

Which access method would be most appropriate if your manager gave you a special cable and told you to use it to configure the switch?

Console

Decimal to Hexadecimal Conversions

Converting decimal numbers to hexadecimal values is straightforward. Follow the steps listed: 1. Convert the decimal number to 8-bit binary strings. 2. Divide the binary strings in groups of four starting from the rightmost position. 3. Convert each four binary numbers into their equivalent hexadecimal digit. -The example provides the steps for converting 168 to hexadecimal. For example, 168 converted into hex using the three-step process: 1. 168 in binary is 10101000. 2. 10101000 in two groups of four binary digits is 1010 and 1000. 3. 1010 is hex A and 1000 is hex 8. -Answer: 168 is A8 in hexadecimal.

Hexadecimal to Decimal Conversion

Converting hexadecimal numbers to decimal values is also straightforward. Follow the steps listed: 1. Convert the hexadecimal number to 4-bit binary strings. 2. Create 8-bit binary grouping starting from the rightmost position. 3. Convert each 8-bit binary grouping into their equivalent decimal digit. This example provides the steps for converting D2 to decimal: 1. D2 in 4-bit binary strings is 1101 and 0010. 2. 1101 and 0010 is 11010010 in an 8-bit grouping. 3. 11010010 in binary is equivalent to 210 in decimal. -Answer: D2 in hexadecimal is 210 in decimal.

Which media uses electrical pulses to represent bits?

Copper

The physical layer of the receiving device passes bits up to which higher level layer?

Data Link

Which protocol stack layer encapsulates data into frames?

Data Link

Metal wires within cables

Data is encoded into electrical impulses

Glass or Plastic Fibers within Cables (Fiber-Optic Cable)

Data is encoded into pulses of light.

Wireless Transmission

Data is encoded via modulation of specific frequencies of electromagnetic waves.

Which attack slows down or crashes equipment and programs?

Denial of Service (DoS)

What is the order of the two addresses in the data link frame?

Destination MAC, Source MAC

Application Layer Name System: DNS & DHCP

Domain Name System. Translates domain names such as cisco.com, into IP addresses.

What is the structure of an IPv4 address called?

Dotted-Decimal Format

What types of standards are developed by the Electronics Industries Alliance (EIA)?

Electric wiring and connectors

What is the name of the process of adding protocol information to data as it moves down the protocol stack?

Encapsulation

What is the process of converting information into the proper form for transmission?

Encoding

What is contained in the trailer of a data-link frame?

Error Detection

Which protocol operates at the network access layer of the TCP/IP model?

Ethernet

Contention-Based Access - CSMA/CD

Examples of contention-based access networks include the following: -Wireless LAN (uses CSMA/CA) -Legacy bus-topology Ethernet LAN (uses CSMA/CD) -Legacy Ethernet LAN using a hub (uses CSMA/CD) -These networks operate in half-duplex mode, meaning only one device can send or receive at a time. This requires a process to govern when a device can send and what happens when multiple devices send at the same time. -If two devices transmit at the same time, a collision will occur. For legacy Ethernet LANs, both devices will detect the collision on the network. This is the collision detection (CD) portion of CSMA/CD. The NIC compares data transmitted with data received, or by recognizing that the signal amplitude is higher than normal on the media. The data sent by both devices will be corrupted and will need to be resent. -PC1 Sends a Frame PC1 has an Ethernet frame to send to PC3. The PC1 NIC needs to determine if any device is transmitting on the medium. If it does not detect a carrier signal (in other words, it is not receiving transmissions from another device), it will assume the network is available to send. -The Hub Receives the Frame The Ethernet hub receives and sends the frame. An Ethernet hub is also known as a multiport repeater. Any bits received on an incoming port are regenerated and sent out all other ports, -The hub Sends the Frame All devices attached to the hub will receive the frame. However, because the frame has a destination data link address for PC3, only that device will accept and copy in the entire frame. All other device NICs will ignore the frame, as shown in the figure.

Which LAN topology is a hybrid topology?

Extended Star

Which network infrastructure might an organization use to provide secure and safe access to individuals who work for a different organization but require access to the organization's data?

Extranet

Which term refers to a network that provides secure access to the corporate offices by suppliers, customers and collaborators?

Extranet

True or False? Data Link addresses are physical so they never change in the data link frame from source to destination.

False

True or false. Wireless LANs operate in full-duplex allowing all devices to send or receive data at the same time so the number of users does not impact performance.

False

True or false. Wireless is not well suited for enterprise networks.

False

True or false? The physical layer is only concerned with wired network connections.

False

True or false? The right-most part of an IP address is used to identify the network that a device belongs to.

False

True or false? When a frame is encoded by the physical layer, all bits are sent over the media at the same time.

False

A college is building a new dormitory on its campus. Workers are digging in the ground to install a new water pipe for the dormitory. A worker accidentally damages a fiber optic cable that connects two of the existing dormitories to the campus data center. Although the cable has been cut, students in the dormitories only experience a very short interruption of network services. What characteristic of the network is shown here?

Fault Tolerance

Having multiple paths to a destination is known as redundancy. This is an example of which characteristic of network architecture?

Fault Tolerance

Which media uses patterns of light to represent bits?

Fiber-Optic

When data is encoded as pulses of light, which media is being used to transmit the data?

Fiber-Optic Cable

Types of Fiber Media

Fiber-optic cables are broadly classified into two types: -Single-mode fiber (SMF) -Multimode fiber (MMF)

Fiber-Optic Cabling Usage

Fiber-optic cabling is now being used in four types of industry: -Enterprise Networks - Used for backbone cabling applications and interconnecting infrastructure devices -Fiber-to-the-Home (FTTH) - Used to provide always-on broadband services to homes and small businesses -Long-Haul Networks - Used by service providers to connect countries and cities -Submarine Cable Networks - Used to provide reliable high-speed, high-capacity solutions capable of surviving in harsh undersea environments at up to transoceanic distances. Search the internet for "submarine cables telegeography map" to view various maps online.

Which option blocks unauthorized access to your network?

Firewall

Which step of the communication process is concerned with properly identifying the address of the sender and receiver?

Formatting

How is an IPv4 address represented?

Four decimal numbers between 0 and 255 separated by periods

What PDU is received by the physical layer for encoding and transmission?

Frame

Which media communication type does not require media arbitration in the data link layer?

Full-Duplex

Which IOS mode are you in if the Switch(config)# prompt is displayed?

Global Configuration Mode

Which duplex communication method is used in WLANs?

Half-Duplex

Which of the following is the name for all computers connected to a network that participate directly in network communication?

Hosts

Which standards organization oversees development of wireless LAN standards?

IEEE

IEEE 802 LAN/MAN Data Link Sublayers

IEEE 802 LAN/MAN standards are specific to Ethernet LANs, wireless LANs (WLAN), wireless personal area networks (WPAN) and other types of local and metropolitan area networks. The IEEE 802 LAN/MAN data link layer consists of the following two sublayers: -Logical Link Control (LLC) - This IEEE 802.2 sublayer communicates between the networking software at the upper layers and the device hardware at the lower layers. It places information in the frame that identifies which network layer protocol is being used for the frame. This information allows multiple Layer 3 protocols, such as IPv4 and IPv6, to use the same network interface and media. -The LLC sublayer takes the network protocol data, which is typically an IPv4 or IPv6 packet, and adds Layer 2 control information to help deliver the packet to the destination node. -Media Access Control (MAC) - Implements this sublayer (IEEE 802.3, 802.11, or 802.15) in hardware. It is responsible for data encapsulation and media access control. It provides data link layer addressing and it is integrated with various physical layer technologies. -The MAC sublayer controls the NIC and other hardware that is responsible for sending and receiving data on the wired or wireless LAN/MAN medium. The MAC sublayer provides data encapsulation: -Frame delimiting - The framing process provides important delimiters to identify fields within a frame. These delimiting bits provide synchronization between the transmitting and receiving nodes. -Addressing - Provides source and destination addressing for transporting the Layer 2 frame between devices on the same shared medium. -Error detection - Includes a trailer used to detect transmission errors. -The MAC sublayer also provides media access control, allowing multiple devices to communicate over a shared (half-duplex) medium. Full-duplex communications do not require access control.

A device receives a data link frame with data and processes and removes the Ethernet information. What information would be the next to be processed by the receiving device?

IP at the internet layer

LAN Topologies

In multiaccess LANs, end devices (i.e., nodes) are interconnected using star or extended star topologies, as shown in the figure. In this type of topology, end devices are connected to a central intermediary device, in this case, an Ethernet switch. An extended star extends this topology by interconnecting multiple Ethernet switches. The star and extended topologies are easy to install, very scalable (easy to add and remove end devices), and easy to troubleshoot. Early star topologies interconnected end devices using Ethernet hubs. At times there may be only two devices connected on the Ethernet LAN. An example is two interconnected routers. This would be an example of Ethernet used on a point-to-point topology. Legacy LAN Topologies Early Ethernet and legacy Token Ring LAN technologies included two other types of topologies: Bus - All end systems are chained to each other and terminated in some form on each end. Infrastructure devices such as switches are not required to interconnect the end devices. Legacy Ethernet networks were often bus topologies using coax cables because it was inexpensive and easy to set up. Ring - End systems are connected to their respective neighbor forming a ring. The ring does not need to be terminated, unlike in the bus topology. Legacy Fiber Distributed Data Interface (FDDI) and Token Ring networks used ring topologies. The figures illustrate how end devices are interconnected on LANs. It is common for a straight line in networking graphics to represent an Ethernet LAN including a simple star and an extended star. Comparison of four physical topologies: star, extended star, bus, and ring

Which connections are specialized ports on a networking device that connect to individual networks?

Interface

This standards organization is responsible for IP address allocation and domain name management.

Internet Assigned Numbers Authority (IANA)

This standards organization is concerned with the Request for Comments (RFC) documents that specify new protocols and update existing ones.

Internet Engineering Task Force (IETF)

Which statement is true about the running configuration file in a Cisco IOS device?

It affects the operation of the device immediately when modified.

Which statement correctly describes frame encoding?

It converts bits into a predefined code in order to provide a predictable pattern to help distinguish data bits from control bits.

What is the function of the shell in an OS?

It interfaces between the users and the kernel.

What is one advantage of using fiber optic cabling rather than copper cabling?

It is able to carry signals much farther than copper cabling.

What is an ISP?

It is an organization that enables individuals and businesses to connect to the Internet.

Verify Windows PC IP Configuration

It is possible to display the IP configuration settings on a Windows PC by using the ipconfig command at the command prompt. The output will show the IPv4 address, subnet mask, and gateway information received from the DHCP server.

What is a characteristic of the LLC sublayer?

It places information in the frame allowing multiple Layer 3 protocols to use the same network interface and media.

What is the Internet?

It provides connections through interconnected global networks.

Which network infrastructure provides access to users and end devices in a small geographical area, which is typically a network in a department in an enterprise, a home, or small business?

LAN

What is another name for the OSI data link layer?

Layer 2

Which type of network topology lets you see which end devices are connected to which intermediary devices and what media is being used?

Logical

Which topology displays networking device layer IP addresses?

Logical Topology

Which delivery method is used to transmit information to one or more end devices, but not all devices on the network?

Multicast

Which of the following fiber-optic cable types can help data travel approximately 500 meters?

Multimode

Which of the following fiber-optic cable types is used within a campus network?

Multimode

Which of the following fiber-optic cable types use light emitting diodes (LEDs) as a data light source transmitter?

Multimode

Which connection physically connects the end device to the network?

NIC (Network Interface Card)

Which memory location on a Cisco router or switch stores the startup configuration file?

NVRAM

Wired Connection to Wireless Router

Network Interface Cards Network interface cards (NICs) connect a device to the network. Ethernet NICs are used for a wired connection, as shown in the figure, whereas wireless local area network (WLAN) NICs are used for wireless. An end-user device may include one or both types of NICs. A network printer, for example, may only have an Ethernet NIC, and therefore, must connect to the network using an Ethernet cable. Other devices, such as tablets and smartphones, might only contain a WLAN NIC and must use a wireless connection.

CISCO - CHAPTER 1

Networking Today

LC-LC Single-mode Patch Cord

Note: Fiber cables should be protected with a small plastic cap when not in use.

SC-SC Multimode Patch Cord

Note: Fiber cables should be protected with a small plastic cap when not in use.

SC-ST Single-mode Patch Cord

Note: Fiber cables should be protected with a small plastic cap when not in use.

ST-LC Multimode Patch Cord

Note: Fiber cables should be protected with a small plastic cap when not in use.

An administrator has just changed the IP address of an interface on an IOS device. What else must be done in order to apply those changes to the device?

Nothing must be done. Changes to the configuration on an IOS device take effect as soon as the command is typed correctly and the Enter key has been pressed.

A network team is comparing physical WAN topologies for connecting remote sites to a headquarters building. Which topology provides high availability and connects some, but not all, remote sites?

Partial Mesh

A network administrator is troubleshooting connectivity issues on a server. Using a tester, the administrator notices that the signals generated by the server NIC are distorted and not usable. In which layer of the OSI model is the error categorized?

Physical Layer

Which type of network topology lets you see the actual location of intermediary devices and cable installation?

Physical Topology

Which feature is being used when connecting a device to the network using an electrical outlet?

Powerline

Which IOS mode allows access to all commands and features?

Privilege EXEC Mode

Which type of access is secured on a Cisco router or switch with the enable secret command?

Privileged EXEC

What is the responsibility of the MAC sublayer?

Provides the method to get the frame on and off the media

With which type of policy, a router can manage the flow of data and voice traffic, giving priority to voice communications if the network experiences congestion?

QoS

Which memory location on a Cisco router or switch will lose all content when the device is restarted?

RAM

What type of cable is used to connect a workstation serial port to a Cisco router console port?

Rollover

BGP and OSPF are examples of which type of protocol?

Routing

Which of the following counters EMI and RFI by using shielding techniques and special connectors?

STP

What characteristic of a network enables it to quickly grow to support new users and applications without impacting the performance of the service being delivered to existing users?

Scalability

When designers follow accepted standards and protocols, which of the four basic characteristics of network architecture is achieved?

Scalability

Confidentiality, integrity, and availability are requirements of which of the four basic characteristics of network architecture?

Security

What is the PDU associated with the transport layer?

Segment

What is the process of dividing a large data stream into smaller pieces prior to transmission?

Segmentation

A Layer 2 switch is used to switch incoming frames from a 1000BASE-T port to a port connected to a 100Base-T network. Which method of memory buffering would work best for this task?

Shared Memory Buffering

Which of the following fiber-optic cable types can travel approximately 100 km?

Single-Mode

Which of the following fiber-optic cable types is used to connect long-distance telephony and cable TV applications?

Single-Mode

Which of the following fiber-optic cable types use lasers in a single stream as a data light source transmitter?

Single-Mode

Spyware and Adware

Software installed on a user device that secretly collects information about the user

Interface

Specialized ports "interface" on a networking device that connect to individual networks. Because routers connect networks, the ports on a router are referred to as network interfaces

During a routine inspection, a technician discovered that software that was installed on a computer was secretly collecting data about websites that were visited by users of the computer. Which type of threat is affecting this computer?

Spyware

Which type of UTP cable is used to connect a PC to a switch port?

Straight-through

What is used to determine the network portion of an IPv4 address?

Subnet Mask

What type of interface has no physical port associated with it?

Switch Virtual Interface (SVI)

This protocol is responsible for guaranteeing the reliable delivery of information.

TCP

Which access method would be the most appropriate in-band access to the IOS over a network connection?

Telnet/SSH

Tera Term

Tera Term (rarely TeraTerm) is an open-source, free, software implemented, terminal emulator (communications) program. It emulates different types of computer terminals, from DEC VT100 to DEC VT382. It supports telnet, SSH 1 & 2 and serial port connections. It also has a built-in macro scripting language (supporting Oniguruma regular expressions) and a few other useful plugins.

Bandwidth Terminology

Terms used to measure the quality of bandwidth include: -Latency -Throughput -Goodput -Latency Latency refers to the amount of time, including delays, for data to travel from one given point to another. In an internetwork, or a network with multiple segments, throughput cannot be faster than the slowest link in the path from source to destination. Even if all, or most, of the segments have high bandwidth, it will only take one segment in the path with low throughput to create a bottleneck in the throughput of the entire network. -Throughput Throughput is the measure of the transfer of bits across the media over a given period of time. Due to a number of factors, throughput usually does not match the specified bandwidth in physical layer implementations. Throughput is usually lower than the bandwidth. There are many factors that influence throughput: -The amount of traffic -The type of traffic -The latency created by the number of network devices encountered between source and destination There are many online speed tests that can reveal the throughput of an internet connection. The figure provides sample results from a speed test. -Goodput There is a third measurement to assess the transfer of usable data; it is known as goodput. Goodput is the measure of usable data transferred over a given period of time. Goodput is throughput minus traffic overhead for establishing sessions, acknowledgments, encapsulation, and retransmitted bits. Goodput is always lower than throughput, which is generally lower than the bandwidth.

Types of Wireless Media

The IEEE and telecommunications industry standards for wireless data communications cover both the data link and physical layers. In each of these standards, physical layer specifications are applied to areas that include the following: -Data to radio signal encoding -Frequency and power of transmission -Signal reception and decoding requirements -Antenna design and construction These are the wireless standards: -Wi-Fi (IEEE 802.11) - Wireless LAN (WLAN) technology, commonly referred to as Wi-Fi. WLAN uses a contention-based protocol known as carrier sense multiple access/collision avoidance (CSMA/CA). The wireless NIC must first listen before transmitting to determine if the radio channel is clear. If another wireless device is transmitting, then the NIC must wait until the channel is clear. Wi-Fi is a trademark of the Wi-Fi Alliance. Wi-Fi is used with certified WLAN devices based on the IEEE 802.11 standards. -Bluetooth (IEEE 802.15) - This is a wireless personal area network (WPAN) standard, commonly known as "Bluetooth." It uses a device pairing process to communicate over distances from 1 to 100 meters. -WiMAX (IEEE 802:16) - Commonly known as Worldwide Interoperability for Microware Access (WiMAX), this wireless standard uses a point-to-multipoint topology to provide wireless broadband access. -Zigbee (IEEE 802.15.4) - Zigbee is a specification used for low-data rate, low-power communications. It is intended for applications that require short-range, low data-rates and long battery life. Zigbee is typically used for industrial and Internet of Things (IoT) environments such as wireless light switches and medical device data collection. -Note: Other wireless technologies such as cellular and satellite communications can also provide data network connectivity. However, these wireless technologies are out of scope for this module.

During the encapsulation process, what occurs at the data link layer for a PC connected to an Ethernet network?

The Physical Address is added.

What is the definition of bandwidth?

The amount of data that can flow from one place to another in a given amount of time

What is the auto-MDIX feature on a switch?

The automatic configuration of an interface for a straight-through or a crossover Ethernet cable connection

Which characteristic describes crosstalk?

The distortion of the transmitted messages from signals carried in adjacent wires

A network administrator is designing a new network infrastructure that includes both wired and wireless connectivity. Under which situation would a wireless connection be recommended?

The end-user device needs mobility when connecting to the network.

Properly Terminated UTP Cable

The figure shows a properly terminated UTP cable. It is a good connector with wires that are untwisted only to the extent necessary to attach the connector. -Note: Improper cable termination can impact transmission performance.

What action will occur if a host receives a frame with a destination MAC address of FF:FF:FF:FF:FF:FF?

The host will process the frame.

When a hostname is configured through the Cisco CLI, which three naming conventions are part of the guidelines? (Choose three.)

The hostname should be: -Fewer than 64 characters in length. -No spaces -Begin with a letter.

What type of network must a home user access in order to do online shopping?

The internet

What is indicated by the term throughput?

The measure of the bits transferred across the media over a given period of time

A wireless LAN is being deployed inside the new one room office that is occupied by the park ranger. The office is located at the highest part of the national park. After network testing is complete, the technicians report that the wireless LAN signal is occasionally affected by some type of interference. What is a possible cause of the signal distortion?

The microwave oven

ping

The ping command can be used to test connectivity to another device on the network or a website on the internet.

RJ-45 UTP Sockets

The socket, shown in the figure, is the female component of a network device, wall, cubicle partition outlet, or patch panel. When terminated improperly, each cable is a potential source of physical layer performance degradation. front and side view of an RJ45 UTP socket, including the color code for wire termination

Internal Threats

There have been many studies that show that the most common data breaches happen because of internal users of the network. This can be attributed to lost or stolen devices, accidental misuse by employees, and in the business environment, even malicious employees. With the evolving BYOD strategies, corporate data is much more vulnerable. Therefore, when developing a security policy, it is important to address both external and internal security threats, as shown in the figure.

Viruses, worms, and Trojan horses

These contain malicious software or code running on a user device.

Traditional Separate Networks

These separate networks could not communicate with each other. Each network used different technologies to carry the communication signal. Each network had its own set of rules and standards to ensure successful communication. Multiple services ran on multiple networks. separate computer, telephone, and broadcast networks

Why are two strands of fiber used for a single fiber optic connection?

They allow for full-duplex connectivity

Identity Theft

This attack steals the login credentials of a user in order to access private data.

Poorly Terminated UTP Cable

This figure shows an example of a badly terminated UTP cable. This bad connector has wires that are exposed, untwisted, and not entirely covered by the sheath.

Hub and Spoke WAN Topology

This is a WAN version of the star topology in which a central site interconnects branch sites through the use of point-to-point links. Branch sites cannot exchange data with other branch sites without going through the central site.

running-config

This is stored in Random Access Memory (RAM). It reflects the current configuration. Modifying a running configuration affects the operation of a Cisco device immediately. RAM is volatile memory. It loses all of its content when the device is powered off or restarted.

startup-config

This is the saved configuration file that is stored in NVRAM. It contains all the commands that will be used by the device upon startup or reboot. Flash does not lose its contents when the device is powered off.

Mesh WAN Topology

This topology provides high availability but requires that every end system is interconnected to every other system. Therefore, the administrative and physical costs can be significant. Each link is essentially a point-to-point link to the other node.

Which of these is a measure of the transfer of bits across the media?

Throughput

Why would a technician enter the command copy startup-config running-config?

To copy an existing configuration into RAM.

What is the purpose of the sequencing function in network communication?

To uniquely label transmitted segments of data for proper reassembly by the receiver.

What is the purpose of the OSI physical layer?

Transmitting bits across the local media

UDP and TCP belong to which layer of the TCP/IP protocol?

Transport

True or false. Standards organizations are usually vendor-neutral.

True

True or false? Frames exchanged between devices in different IP networks must be forwarded to a default gateway.

True

Which procedure is used to reduce the effect of crosstalk in copper cables?

Twisting opposing circuit wire pairs together

Which of the following is the most common network media?

UTP

UTP Cabling Standards and Connectors

UTP cabling conforms to the standards established jointly by the TIA/EIA. Specifically, TIA/EIA-568 stipulates the commercial cabling standards for LAN installations and is the standard most commonly used in LAN cabling environments. Some of the elements defined are as follows: -Cable types -Cable lengths -Connectors -Cable termination -Methods of testing cable -The electrical characteristics of copper cabling are defined by the Institute of Electrical and Electronics Engineers (IEEE). IEEE rates UTP cabling according to its performance. Cables are placed into categories based on their ability to carry higher bandwidth rates. For example, Category 5 cable is used commonly in 100BASE-TX Fast Ethernet installations. Other categories include Enhanced Category 5 cable, Category 6, and Category 6a. -Cables in higher categories are designed and constructed to support higher data rates. As new gigabit speed Ethernet technologies are being developed and adopted, Category 5e is now the minimally acceptable cable type, with Category 6 being the recommended type for new building installations. The figure shows three categories of UTP cable: -Category 3 was originally used for voice communication over voice lines, but later used for data transmission. -Category 5 and 5e is used for data transmission. Category 5 supports 100Mbps and Category 5e supports 1000 Mbps -Category 6 has an added separator between each wire pair to support higher speeds. -Category 6 supports up to 10 Gbps. -Category 7 also supports 10 Gbps. -Category 8 supports 40 Gbps. -Some manufacturers are making cables exceeding the TIA/EIA Category 6a specifications and refer to these as Category 7. The figure shows the difference in construction between categories of UTP cable. At the top is category 3 with four wires. In the middle is category 5 and 5e with four twisted wire pairs. At the bottom is category 6 with four twisted wire pairs, each with a plastic separator. -UTP cable is usually terminated with an RJ-45 connector. The TIA/EIA-568 standard describes the wire color codes to pin assignments (pinouts) for Ethernet cables.

Converged Networks

Unlike dedicated networks, converged networks are capable of delivering data, voice, and video between many different types of devices over the same network infrastructure. This network infrastructure uses the same set of rules, agreements, and implementation standards. Converged data networks carry multiple services on one network.

To save changes made to the running configuration to the startup configuration file....

Use the copy running-config startup-config privileged EXEC mode command.

To view the startup configuration..

Use the show startup-config privileged EXEC command.

Which IOS mode are you in if the Switch> prompt is displayed?

User EXEC Mode

A router with a valid operating system contains a configuration file stored in NVRAM. The configuration file has an enable secret password but no console password. When the router boots up, which mode will display?

User EXEC mode

What is the default SVI on a Cisco switch?

VLAN1

An employee wants to access the network of the organization remotely, in the safest possible way. What network feature would allow an employee to gain secure remote access to a company network?

VPN

Which feature is a good conferencing tool to use with others who are located elsewhere in your city, or even in another country?

Video Communications

Which option creates a secure connection for remote workers?

Virtual Private Network (VPN)

Which option describes malicious code running on user devices?

Virus, Worm, or Trojan horse

What kind of network would use point-to-point, hub and spoke, or mesh topologies?

WAN

Which network infrastructure provides access to other networks over a large geographical area, which is often owned and managed by a telecommunications service provider?

WAN

Which media uses patterns of microwaves to represent bits?

Wireless

Which feature uses the same cellular technology as a smart phone?

Wireless Broadband

Which option describes a network attack that occurs on the first day that a vulnerability becomes known?

Zero-day or Zero-hour

Which of the following wireless standards is best suited for industrial and IoT environments?

Zigbee

Which is the command to configure a banner to be displayed when connecting to a switch?

banner motd $ Keep out $ --??-- banner motd # Keep out # --??--

How is the privileged EXEC mode access secured on a switch?

enable secret class

The startup config is removed by using the...

erase startup-config -Confirm by pressing Enter

Which switching method has the lowest level of latency?

fast-forward

What is the command to assign the name "Sw-Floor-2" to a switch?

hostname Sw-Floor-2

Which command enables password authentication for user EXEC mode access on a switch?

login

What does the term "attenuation" mean in data communication?

loss of signal strength as distance increases

show running-config

privileged EXEC mode command is used to view the running config. As shown in the example, the command will list the complete configuration currently stored in RAM.

Which two devices are intermediary devices?

routers and switches

Which command encrypts all plaintext passwords access on a switch?

service password-encryption

What three items are contained in an Ethernet header and trailer? (Choose three.)

source MAC address / destination MAC address / error-checking information

Which switching method uses the CRC value in a frame?

store-and-forward

Which frame forwarding method receives the entire frame and performs a CRC check to detect errors before forwarding the frame?

store-and-forward switching

With the use of unshielded twisted-pair copper wire in a network, what causes crosstalk within the cable pairs?

the magnetic field around the adjacent pairs of wire