ESYS 63A & CAS 83 Chapter 5 Networking Concepts

wireless router

A wireless router connects multiple wireless devices to the network. In addition, a wireless router often includes a switch so that multiple wired devices can connect to the network. page 322

Activity = Fiber Cables and Connectors

Activity = Fiber Cables and Connectors

Activity = Internet Connection Types

Activity = Internet Connection Types

Activity = Ports for Protocols

Activity = Ports for Protocols page 377

Activity = TCP vs UDP

Activity = TCP vs UDP page 377

DSL (digital subscriber line)

High-speed Internet connection technology that is always on and uses a regular telephone line for connectivity. Voice and data signals are carried on different frequencies on the copper telephone wires. A filter prevents DSL signals from interfering with phone signals. DSL comes in several varieties, including asynchronous (ADSL) and synchronous (SDSL), and many speeds. Typical home-user DSL connections are ADSL with faster download speeds than upload speeds.

Physical Layer (OS)

Layer 1 of the OSI model, the physical layer or layer 1 is the first and lowest layer. It is made up of physical components such as cables and NICs and concentrators. This layer may be implemented by a PHY chip. ... The physical layer provides an electrical, mechanical, and procedural interface to the transmission medium. page 335 & page 345

Network Layer (OSI)

Layer 3 of the OSI model, the layer that provides data routing paths for network communication. Data is transferred in the form of packets via logical network paths in an ordered format controlled by the network layer. page 335

Transport Layer (OSI)

Layer 4 of the OSI model, Provides reliable transport and flow control across a network. The two most common protocols used by the transport layer are the transmission control protocol (TCP) and the user datagram protocol (UDP). Both TCP and UDP aid the transport layer in managing communications between multiple computer resources. page 335

sense of CSMA/CD

Sense - Each device listens to the wire to determine if it is clear to send data. page 342

shared key authentication

Shared key authentication - Provides mechanisms to authenticate and encrypt data between a wireless client and AP or wireless router. page 344

OSI vs TCP/IP Model

The OSI model and the TCP/IP model are both reference models used to describe the data communication process. The TCP/IP model is used specifically for the TCP/IP suite of protocols, and the OSI model is used for the development of communication standards for equipment and applications from different vendors. The TCP/IP model performs the same process as the OSI model, but uses four layers instead of seven. The figure shows how the layers of the two models compare. page 341

WPA (WiFi Protected Access) Encryption

Wi-Fi Protected Access (WPA) - This standard uses WEP, but secures the data with the much stronger Temporal Key Integrity Protocol (TKIP) encryption algorithm. TKIP changes the key for each packet, making it much more difficult to hack. page 344

copper network cable media types

copper network cables include coaxial and twisted pair types of cables.

DHCP (Dynamic Host Configuration Protocol) expanded

A network service that provides automatic assignment of IP addresses and other TCP /IP configuration information. Before a computer on the network can take advantage of the DHCP services, the computer must be able to identify the server on the local network. A computer can be configured to accept an IP address from a DHCP server by selecting the Obtain an IP address automatically option in the NIC configuration window, as shown in Figure 1. When a computer is set to obtain an IP address automatically, all other IP addressing configuration boxes are not available. The DHCP settings are configured the same for a wired or wireless NIC. page 370

Activity = network tools

Activity = network tools

Subnet Masking

An IPv4 address is composed of two parts. The first part identifies the network. The second part identifies a host on that network. BOTH parts are required. When a computer prepares data to send out on the network, it must determine whether to send data directly to the intended receiver or to a router. It will send it directly to the receiver if the receiver is on the same network. Otherwise, it will send the data to a router. A router then uses the network portion of the IP address to route traffic between different networks. Computers and routers use the subnet mask to calculate the network portion of the destination IPv4 address. Like an IPv4 address, the subnet mask is represented in dotted-decimal. For example, the subnet mask for the IPv4 address 192.168.200.8 might be 255.255.255.0, as shown in Figure 1. A computer uses both the address and the subnet mask to determine the network portion of the address. It does so at the binary level. In Figure, the 192.168.200.8 address and 255.255.255.0 subnet mask are converted to their binary equivalents. An octet with the decimal value 255 is 8 ones in binary. A one bit in the subnet mask means that bit is part of the network portion. So the first 24 bits of the 192.168.200.8 address are network bits. The last 8 bits are host bits. page 365

backoff algorithm

Calculates random times in which the end station tries transmitting again. This random time is typically in 1 or 2 milliseconds (ms). This sequence occurs every time there is a collision on the network and can reduce Ethernet transmission by up to 40 percent. page 342

carrier of CSMA/CD

Carrier - This is the wire used to transmit data. page 342

collision detection of CSMA/CD

Collision Detection - A collision causes a doubling of voltage on the wire, which is detected by the devices' NICs. page 342

fiber optic cable

Fiber optic cables are made of glass or plastic and use light to transmit data. They have a very high bandwidth, which enables them to carry large amounts of data. At some point in your connection to the internet, your data will cross a fiber network. Fiber is used in backbone networks, large enterprise environments and large data centers. Older copper cabling infrastructures closer to home and businesses are increasingly being replaced with fiber.

CSMA/CA is an acronym for: a. Carrier Sense Multiple Access with Collision Acknowledgment b. Carrier Sense Mode Access with Carrier Avoidance c. Carrier Sense Multiple Access with Collision Avoidance d. Carrier Sensory Multiple Access without Collision Acknowledgment e. Carrier Sense Multiple Acknowledgment with Collision Avoidance

IEEE 802.11 is the standard that specifies connectivity for wireless networks. Wireless networks use Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA). CMSA/CA does not detect collisions but attempts to avoid them by waiting before transmitting. Each device that transmits includes in the frame 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, as shown in the figure. This means that wireless devices operate in half-duplex mode. The transmission efficiency of an AP or wireless router is reduced as more devices are attached. page 343

WPA2 (Wi-Fi Protected Access 2)

IEEE 802.11i/WPA2 - IEEE 802.11i is now the industry standard for securing WLANs. The Wi-Fi alliance version is called WPA2. 802.11i and WPA2 both use the Advanced Encryption Standard (AES) for encryption. AES is currently considered the strongest encryption protocol. Since 2006, any device that bears the Wi-Fi Certified logo is WPA2 certified. Therefore, modern WLANs should always use the 802.11i/WPA2 standard. page 344

IPv6 address examples

IPv6 addresses are 128 bits in length and written as a string of hexadecimal values. Every 4 bits is represented by a single hexadecimal digit for a total of 32 hexadecimal values. The examples shown in Figure 1 are fully expanded IPv6 addresses. Two rules help reduce the number of digits needed to represent an IPv6 address. page 367

IPv6 Address formats

IPv6 addressing will eventually replace IPv4 addressing. IPv6 overcomes the limitations of IPv4 and is a powerful enhancement with features that better suit current and foreseeable network demands. The 32-bit IPv4 address space provides approximately 4,294,967,296 unique addresses. IPv6 address space provides 340,282,366,920,938,463,463,374,607,431,768,211,456 addresses, or 340 undecillion addresses, which is roughly equivalent to every grain of sand on Earth. The figure provides a visual to compare the IPv4 and IPv6 address space. page 367

static addressing paths Win 8 & Win 7

In Windows 7, use the following path: Start > Control Panel > Network and Sharing Center > Change adapter setting > right-click Local Area Connection > Properties > TCP/IPv4 or TCP/IPv6 > Properties > Use the following IP address > Use the following DNS server addresses > OK > OK In Windows 8.0 and 8.1, use the following path: PC Settings > Control Panel > Network and Internet > Network and Sharing Center > Change adapter setting > right-click Ethernet > Properties > TCP/IPv4 or TCP/IPv6 > Properties > Use the following IP address > Use the following DNS server addresses > OK > OK page 369

static addressing

In a network with a small number of hosts, it is easy to manually configure each device with the proper IP address. A network administrator who understands IP addressing should assign the addresses and should know how to choose a valid address for a particular network. The IP address that is assigned is unique for each host within the same network or subnet. This is known as static IP addressing. To configure a static IP address on a host, go to the TCP/IPv4 Properties window of the NIC, as shown in the figure. You can assign the following IP address configuration information to a host: IP address - identifies the computer on the network Subnet mask - is used to identify the network on which the computer is connected Default gateway - identifies the device that the computer uses to access the Internet or another network Optional values - such as the preferred Domain Name System (DNS) server address and the alternate DNS server address page 368

OSI Model

In the early 1980s, the International Standards Organization (ISO) developed the Open Systems Interconnect (OSI) reference model to standardize the way devices communicate on a network. This model was a major step toward ensuring interoperability between network devices. The OSI model divides network communications into seven distinct layers, as shown in the figure. Although other models exist, most network vendors today build their products using this framework. Note: Mnemonics can help you remember the seven layers of the OSI. Two examples are, "All People Seem To Need Data Processing" and "Please Do Not Throw Sausage Pizza Away". page 335

Activity = Packet Tracer = Adding computers to existing network

In this Packet Tracer activity, you will configure the computers to use DHCP, configure static addressing, use ipconfig to retrieve host IP information, and use ping to verify connectivity. page 373

Internet Control Message Protocol (ICMP)

Internet Control Message Protocol (ICMP) is used by devices on a network to send control and error messages to computers and servers. There are several different uses for ICMP, such as announcing network errors, announcing network congestion, and troubleshooting. page 371

ipconfig /all command

Ipconfig displays all current TCP/IP network configuration values and refreshes Dynamic Host Configuration Protocol (DHCP) and Domain Name System (DNS) settings. page 363

Data Link Layer (OSI)

Layer 2 of the OSI model, The three main functions of the data link layer are to deal with transmission errors, regulate the flow of data, and provide a well-defined interface to the network layer. This layer is the protocol layer that transfers data between adjacent network nodes in a wide area network or between nodes on the same local area network segment. page 335

Mobile Hotspot & Tethering

Many cell phones provide the ability to connect other devices, as shown in the figure. This connection, known as tethering, can be made using Wi-Fi, Bluetooth, or by using a USB cable. Once a device is connected, it is able to use the phone's cellular connection to access the Internet. When a cellular phone allows Wi-Fi devices to connect and use the mobile data network, it is called a mobile hotspot.

multiple access of CSMA/CD

Multiple Access - There can be many devices accessing the network at the same time. page 342

Activity = Identify Network Devices

Network devices, or networking hardware, are physical devices that are required for communication and interaction between hardware on a computer network. page 351

FTP (File Transfer Protocol)

Protocol in Application Layer 7 for File Transfers: FTP is used to transfer files between computers on a network. You can use FTP to exchange files between computer accounts, transfer files between an account and a desktop computer, or access online software archives. page 337

TFTP (Trivial File Transfer Protocol)

Protocol in Application Layer 7 for File Transfers: It is also used to transfer firmware images and configuration files to network appliances like routers, firewalls, IP phones, etc. Today, TFTP is virtually unused for Internet transfers. ... TFTP is a simple protocol for transferring files, implemented on top of the UDP/IP protocols using well-known port number 69. page 337

DHCP (Dynamic Host Configuration Protocol)

Protocol in Application Layer 7 for Host Configuration. A network service that provides automatic assignment of IP addresses and other TCP /IP configuration information. Dynamically assigns IP addresses to client workstations at startup. Allows the addresses to be reused when no longer needed. page 336

BOOTP

Protocol in Application Layer 7 for Host Configuration. It enables a workstation to discover its own IP address, the IP address of a BOOTP server on the network, and a file to be loaded into memory to boot the machine. page 336

HTTP (Hypertext Transfer Protocol)

Protocol in Application Layer 7 for Web: HTTP is the underlying protocol used by the World Wide Web and this protocol defines how messages are formatted and transmitted, and what actions Web servers and browsers should take in response to various commands. page 337

PPP (Point-to-point protocol)

Protocol in Data Link Layer 2: In computer networking, Point-to-Point Protocol (PPP) is used to establish a direct connection between two nodes. ... It can provide connection authentication, transmission encryption, and compression. page 338

UDP (User Datagram Protocol)

Protocol in Transport Layer 4 for: User Datagram Protocol (UDP) is part of the Internet Protocol suite used by programs running on different computers on a network. UDP is used to send short messages called datagrams but overall, it is an unreliable, connectionless protocol. UDP is officially defined in RFC 768. page 337

TCP (Transmission Control Protocol)

Protocol in Transport Layer 4 for:TCP is one of the main protocols in TCP/IP networks. Whereas the IP protocol deals only with packets, TCP enables two hosts to establish a connection and exchange streams of data. TCP guarantees delivery of data and also guarantees that packets will be delivered in the same order in which they were sent. page 337

Interface Drivers Network Access Layer

Provides instruction to a machine for the control of a specific interface on a network device. page 328

Rule 1 of IPv6

Rule 1 - Omit Leading Os The first rule to help reduce the notation of IPv6 addresses is to omit any leading 0s (zeros) in any 16-bit section. For example: 01AB can be represented as 1AB 09F0 can be represented as 9F0 0A00 can be represented as A00 00AB can be represented as AB page 367

Configuring Alternate IP Settings

Setting up an alternate IP configuration in Windows simplifies moving between a network that requires using DHCP and a network that uses static IP settings. If a computer cannot communicate with the DHCP server on the network, Windows uses the alternate IP configuration assigned to the NIC. The alternate IP configuration also replaces the APIPA address that is assigned by Windows when a DHCP server cannot be contacted. To create the alternate IP configuration, as shown in Figure, click the Alternate Configuration tab located in the NIC Properties window. The Alternate Configuration tab only shows when Obtain an IP address automatically is selected. page 371

Single-mode fiber (SMF)

Single-mode fiber (SMF) - Consists of a very small core and uses laser technology to send a single ray of light, as shown in Figure 1. Popular in long-distance situations spanning hundreds of kilometers, such as those required in long haul telephony and cable TV applications. page 359

Activity = OSI vs TCPIP Layers

The OSI model and the TCP/IP model are both reference models used to describe the data communication process. The TCP/IP model is used specifically for the TCP/IP suite of protocols, and the OSI model is used for the development of communication standards for equipment and applications from different vendors. The TCP/IP model performs the same process as the OSI model, but uses four layers instead of seven. page 341

Wireless Security

The best way to secure a wireless network is to use authentication and encryption. Two types of authentication were introduced with the original 802.11 standard, authentication and shared key. page 344

MAC vs IP address

The fingerprint and addressed letters in Figure 1 are two ways of identifying a person. A person's fingerprints usually do not change. They provide a way to physically identify people. The mailing address of a person can change, as it relates to where the person lives or picks up mail. Devices that are attached to a network have two addresses that are similar to a person's fingerprints and a person's mailing address. These two types of addresses are the Media Access Control (MAC) address and the IP address. The MAC address is hard coded onto the network interface card (NIC) by the manufacturer. The address stays with the device regardless of what network the device is connected. A MAC address is 48 bits and can be represented in one of the three hexadecimal formats shown in Figure. Note: The binary and hexadecimal numbering systems are common in networking technologies. Converting between decimal, binary, and hexadecimal numbering systems is beyond the scope of this course. Search the Internet to learn more about these numbering systems.

PDU (protocol data unit)

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. page 338

Transport Layer Role

The transport layer is responsible for establishing a temporary communication session between two applications and delivering data between them. As shown in the figure, the transport layer is the link between the application layer and the lower layers that are responsible for network transmission. page 373

TCP vs UDP (transport layer protocols)

The two protocols that operate at the transport layer are TCP and User Datagram Protocol (UDP). TCP is considered a reliable, full-featured transport layer protocol, which ensures that all of the data arrives at the destination. In contrast, UDP is a very simple transport layer protocol that does not provide for any reliability. IP uses these transport protocols to enable hosts to communicate and transfer data. Figure highlights the TCP and UDP properties. page 375

De-encapsulation (Decapsulation)

This process is reversed at the receiving host, and is known as de-encapsulation. De-encapsulation is the process used by a receiving device to remove one or more of the protocol headers. The data is de-encapsulated as it moves up through the layers towards the end-user application. page 340

VPN

VPN = Virtual Private Network Allows a secure private connection over a public network, using an encrypted 'tunnel'. For example, a remote computer can securely connect to a LAN, as though it were physically connected.

WLAN (Wireless Local Area Network)

WLAN (Wireless Local Area Network) is a LAN communication technology in which radio, microwave or infrared links take the place of physical cables

Encapsulation Example

When sending messages on a network, the encapsulation process works from top to bottom. At each layer, the upper layer information is considered data within the encapsulated protocol. For example, the TCP segment is considered data within the IP packet. page 339

Broadband

a high-capacity transmission technique using a wide range of frequencies, which enables a large number of messages to be communicated simultaneously over the same medium. Examples include DSL, cable, ISDN, satellite and cellular.

WiFi vs ZigBee vs Z-Wave

https://www.howtogeek.com/441296/wi-fi-vs.-zigbee-and-z-wave-which-is-better/

NAT

network address translation = NAT translates IP addresses from a private network into globally unique public IP addresses. NAT helps improve security and decrease the number of IP addresses an organization needs. page 337

packets Vs frames

packets are Network Layer 3 PDUs (protocol data units) frames are Data Link Layer 2 PDUs (protocol data units)

network media icons

symbols representing network media page 324

WAN

Wide Area Network; largest type of network in terms of geographic area; largest WAN is the Internet. continents to around the world. A WAN connects multiple networks that are in geographically separated locations. The distinguishing characteristic of a WAN is that it is owned by a service provider. Individuals and organizations contract for WAN services. The most common example of a WAN is the Internet. The Internet is a large WAN that is composed of millions of interconnected networks. In the figure, the Tokyo and Moscow networks are connected through the Internet. page 329

Concentrator

intermediary devices ensure that data flows from one host device to another host device. The most common intermediary devices are routers, switches, access point and modems. page 322

modem

modulation-demodulation A modem connects to the Internet through an Internet Service Provider (ISP). There are three basic types of modems. Modems convert a computer's digital data into a format that can be transmitted on the ISP's network. An analog modem converts digital data to analog signals for transmission over analog phone lines. A digital subscriber line (DSL) modem connects a user's network directly to the digital infrastructure of the phone company. A cable modem connects the user's network to a cable service provider, which typically uses a hybrid fiber coax (HFC) network. A modem is used to connect a home or small office to the Internet. page 323 & 345

network

two or more computers connected to share information and/or resources while using the same protocols. page 320

CAT 6 UTP

100 Mbps and gigabit networks

WEP (Wired Equivalent Privacy)

Wired Equivalent Privacy (WEP) - This was the original 802.11 specification securing WLANs. However, the encryption key never changes when exchanging packets, making it easy to hack. page 344

PING

a DOS command that tests connectivity and isolates hardware problems and any mismatched configurations. Ping works by sending an ICMP echo request to a destination computer or other network device. The receiving device then sends back an ICMP echo reply message to confirm connectivity. Echo requests and echo replies are test messages that determine if devices can send packets to each other. With Windows, four ICMP echo requests (pings) are sent to the destination computer, as shown in Figure 2. If it is reachable, the destination computer responds with four ICMP echo replies. The percentage of successful replies can help you to determine the reliability and accessibility of the destination computer. Other ICMP messages report undelivered packets and whether a device is too busy to handle the packet. You can also use ping to find the IP address of a host when that host's name is known. If you ping the name of a website, for example, cisco.com, as shown in Figure, the IP address of the server is displayed. page 371

SMTP (Simple Mail Transfer Protocol)

Protocol in Application Layer 7 for email. This is the protocol used for sending e-mail over the Internet. Your e-mail client (such as Outlook, Eudora, or Mac OS X Mail) uses SMTP to send a message to the mail server, and the mail server uses SMTP to relay that message to the correct receiving mail server. Basically, SMTP is a set of commands that authenticate and direct the transfer of electronic mail. When configuring the settings for your e-mail program, you usually need to set the SMTP server to your local Internet Service Provider's SMTP settings (i.e. "smtp.yourisp.com"). However, the incoming mail server (IMAP or POP3) should be set to your mail account's server (i.e. hotmail.com), which may be different than the SMTP server. page 337

DNS (Domain Name System)

Protocol in Application Layer 7 that translates domain names, such as cisco.com into IP addresses. page 336

ICMP (Internet Control Message Protocol)

Protocol in Network Layer 3 for IP Support: A core protocol in the TCP/IP suite that notifies the sender that something has gone wrong in the transmission process and that packets were not delivered.

EIGRP (Enhanced Interior Gateway Routing Protocol)

Protocol in Network Layer 3 for Routing: Enhanced Interior Gateway Routing Protocol (EIGRP) is an advanced distance-vector routing protocol that is used on a computer network for automating routing decisions and configuration. The protocol was designed by Cisco Systems as a proprietary protocol, available only on Cisco routers. page 338

OSPF (Open Shortest Path First)

Protocol in Network Layer 3 for Routing: Open Shortest Path First (OSPF) is a routing protocol for Internet Protocol (IP) networks. It uses a link state routing (LSR) algorithm and falls into the group of interior gateway protocols (IGPs), operating within a single autonomous system (AS). It is defined as OSPF Version 2 in RFC 2328 (1998) for IPv4. page 338

IP (Internet Protocol)

Protocol in Network Layer 3 for: - receiving message units from the transport layer. - packages messages into packets. - addresses packets for end-to-end delivery over an internetwork. page 337

Port numbers used by TCP/UDP

TCP and UDP use a source and destination port number to keep track of application conversations. The source port number is associated with the originating application on the local device. The destination port number is associated with the destination application on the remote device. The source port number is dynamically generated by the sending device. This process allows multiple conversations to occur at the same time for the same application. For example, when you use a web browser, you can have more than one tab open at a time. The destination port number is 80 for regular web traffic or 443 for secure web traffic. But the source port will be different for each tab opened. This is how your computer knows which browser tab to deliver the web content. Similarly, other network applications like email and file transfer have their own assigned port numbers. A list of the most common well-known port numbers are shown in the figure. page 377

TCP

TCP transport is analogous to sending packages that are tracked from source to destination. If a shipping order is broken up into several packages, a customer can check online to see the order of the delivery. With TCP, there are three basic operations of reliability: Numbering and tracking data segments transmitted to a specific device from a specific application. Acknowledging received data. Retransmitting any unacknowledged data after a certain period of time. page 376

MAC address format

A MAC address is 48 bits and can be represented in one of the three hexadecimal formats shown in Figure. Note: The binary and hexadecimal numbering systems are common in networking technologies. Converting between decimal, binary, and hexadecimal numbering systems is beyond the scope of this course. Search the Internet to learn more about these numbering systems.

Transport Layer Features

Data flowing between a source application and a destination application is known as a conversation. A computer can maintain multiple conversations between multiple applications at the same time, as shown in the figure. This is possible because of the three main features of the transport layer: Tracking individual conversation between applications - a device can have multiple applications that are using the network at the same time. Segmenting Data and Reassembling Segments - a sending device segments application data into blocks that are an appropriate size. A receiving device reassembles the segments into application data. Identifying the Applications - To pass data streams to the proper applications, the transport layer must identify the target application. To accomplish this, the transport layer assigns each application an identifier called a port number. page 373

converting IP address to binary

Each number separated by a period is called an octet because it represents 8 bits. Therefore, the address 192.168.200.8 has four octets. Each bit in an octet can be either a 1 (on) or a 0 (off). Also, each bit in an octet represents a value. The rightmost bit represents a 1. Each bit to its left is doubled, so that the leftmost bit represents 128. To convert the binary address, add the values of every bit that is a 1 in each octet, as shown in Figure. page 364

Ethernet

Ethernet protocols describe the rules that control how communication occurs on an Ethernet network. The Ethernet protocol is by far the most widely used one. Ethernet uses an access method called CSMA/CD (Carrier Sense Multiple Access/Collision Detection). This is a system where each computer listens to the cable before sending anything through the network. page 338

Session Layer (OSI)

Layer 5 of the OSI model, session layer is the fifth layer, which controls the connections between multiple computers. The session layer tracks the dialogs between computers, which are also called sessions. page 335

Presentation Layer (OSI)

Layer 6 of the OSI model, It is used to present data to the application layer (layer 7) in an accurate, well-defined and standardized format. The presentation layer is sometimes called the syntax layer. Transforms data formats to provide a standard interface for the application layer. page 335

Application layer (OSI model)

Layer 7 of the OSI model, It consists of protocols that focus on process-to-process communication across an IP network and provides a firm communication interface and end-user services. page 335

Open standards

Open standards encourage interoperability, competition, and innovation. They also guarantee that no single company's product can monopolize the market, or have an unfair advantage over its competition. A good example of this is when purchasing a wireless router for the home. There are many different choices available from a variety of vendors. All of these choices incorporate standard protocols such as Internet Protocol version 4 (IPv4), Dynamic Host Configuration Protocol (DHCP), 802.3 (Ethernet), and 802.11 (Wireless LAN). These are open standards and protocols. page 333

Open System Authentication (OSA)

Open system authentication - Any wireless device can connect to the wireless network. This should only be used in situations where security is of no concern. page 344

IMAP (Internet Message Access Protocol)

Protocol in Application Layer 7 for email. The easiest way to understand how IMAP works is by thinking of it as an intermediary between your email client and your email server. Email servers are always used when sending and receiving email messages. With IMAP, though, they remain on the server unless you explicitly delete them from it. The Internet Message Access Protocol (IMAP) is a mail protocol used for accessing email on a remote web server from a local client. IMAP and POP3 are the two most commonly used Internet mail protocols for retrieving emails. Both protocols are supported by all modern email clients and web servers. page 337

POP (Post Office Protocol)

Protocol in Application Layer 7 for email. Post Office Protocol (POP) is a type of computer networking and Internet standard protocol that extracts and retrieves email from a remote mail server for access by the host machine. POP is an application layer protocol in the OSI model that provides end users the ability to fetch and receive email. page 337

Adaptive Frequency Hopping (AFH)

The Bluetooth standard incorporates Adaptive Frequency Hopping (AFH). AFH allows signals to "hop" around using different frequencies within the Bluetooth range, thereby reducing the chance of interference when multiple Bluetooth devices are present. page 328

Ethernet cable standards

The IEEE 802.3 standard defines several physical implementations that support Ethernet. The figure summarizes the standards of different Ethernet cable types. 1000BASE-T is the most commonly implemented Ethernet architecture today. The name indicates the features of the standard: The 1000 represents a speed of 1000 Mb/s or 1 Gb/s. BASE represents baseband transmission. In baseband transmission, the entire bandwidth of a cable is used for one type of signal. The T represents twisted-pair copper cabling. 10Base-T (Cat 3), 100Base-TX (Cat 5), 1000Base-T (Cat 5e, 6), 10GBase-T (Cat 6a, 7) page 342

TCP/IP vs OSI Protocols

The Open Systems Interconnection (OSI) protocol stack is seldom used in practice, but is often used as a reference point in discussions of other protocols. This figure shows the rough correspondence between the layers of the widely used TCP/IP protocols and the OSI model layers. Application programs in TCP/IP networks handle the functions of the top two OSI layers and part of the third, for example interpreting character codes, authenticating user passwords, and encrypting and decrypting data. The TCP/IP transport layer assumes some of the OSI session layer functionality. IP is simpler than the OSI network layer protocol, with the data link layer doing more work. OSI and TCP/IP both contended for acceptance for a time, but the inclusion of TCP/IP in Berkeley UNIX, Microsoft Windows, and the Apple Macintosh operating system, sealed the fate of OSI. Although OSI is seldom used, it was historically important. Before the OSI standardization effort (1979), computer networks used proprietary protocols. The two leaders were System Network Architecture from IBM and DECNet from Digital Equipment Corporation. These worked as long as you used one or the other, but they were incompatible. OSI defined a protocol stack that was not proprietary, but open for anyone to implement and use. It paved the way for TCP/IP. Today, computers from any manufacturer, running any operating system can communicate as long as they are all running TCP/IP.

TCP/IP (Transmission Control Protocol/Internet Protocol)

The TCP/IP model was created by researchers in the U.S. Department of Defense (DoD). It consists of layers that perform functions necessary to prepare data for transmission over a network. Figure 1 shows the four layers of the TCP/IP model. TCP/IP stands for two important protocols in the suite: Transmission Control Protocol (TCP) and Internet Protocol (IP). TCP is responsible for reliable delivery. The Internet Protocol (IP) is responsible for adding source and destination addressing to the data. But the TCP/IP model includes many other protocols in addition to TCP and IP. These protocols are the dominant standard for transporting data across networks and the Internet. page 336

ARP (address resolution protocol)

The address resolution protocol (arp) is a protocol used by the Internet Protocol (IP) [RFC826], specifically IPv4, to map IP network addresses to the hardware addresses used by a data link protocol. The protocol operates below the network layer as a part of the interface between the OSI network and OSI link layer. page 338

UDP Functions

UDP is similar to placing a regular, non-registered, letter in the mail. The sender of the letter is not aware of the availability of the receiver to receive the letter. Nor is the post office responsible for tracking the letter or informing the sender if the letter does not arrive at the final destination. UDP provides the basic functions for delivering data segments between the appropriate applications, with very little overhead and data checking. UDP is known as a best-effort delivery protocol. In the context of networking, best-effort delivery is referred to as unreliable because there is NO acknowledgment that the data is received at the destination. page 376

Classful IP addressing

When IPv4 was first specified in 1981, addresses were divided into three classes, as shown in Figure 1. The value of the first octet in an IPv4 address indicates which class it belongs to. Each class was assigned a default subnet mask. page 365

DHCP Server

A DHCP server can automatically assign the following IP address configuration information to a host: IP address Subnet mask Default gateway Optional values, such as a DNS server address page 370

Cable

A cable internet connection does not use telephone lines. Cable uses coaxial cable lines originally designed to carry cable television. A cable modem connects your computer to the cable company. You can plug your computer directly into the cable modem. However, connecting a routing device to the modem allows multiple computers to share the connection to the internet.

Encapsulation Process

A message begins at the top application layer and moves down the TCP/IP layers to the bottom network access layer. As application data is passed down through the layers, protocol information is added at each level. This is known as the encapsulation process. page 338

Automatic Private IP Addressing (APIPA)

A networking feature in operating systems that enables DHCP clients to self-configure an IP address and subnet mask automatically when a DHCP server isn't available. After boot up, a computer continually requests an IP address from a DHCP server until one is received. If your computer cannot communicate with the DHCP server to obtain an IP address, the Windows OS automatically assigns an Automatic Private IP Addressing (APIPA) address. This local-link address is in the range of 169.254.0.0 to 169.254.255.255. Local-link means your computer can only communicate with computers connected to the same network within this IP address range. page 370

Wireless standards 802.11 A Distance Speed Frequency

IEEE 802.11, or Wi-Fi, refers to a collective group of standards that specify the radio frequencies, speeds, and other capabilities for WLANs. Various implementation of the IEEE 802.11 standard have been developed over the years, as shown in the figure. The 802.11a, 802.11b, and 802.11g standards should be considered legacy. New WLANs should implement 802.11ac devices. Existing WLAN implementations should upgrade to 802.11ac when purchasing new devices. page 343

Classless Inter-Domain Router (CIDR)

In the early 1990s, it was clear to network engineers that the classful IPv4 addressing system would eventually run out of space. Many businesses were too large for a Class C network address, which only had 254 host addresses. But they were too small for a Class B network address with 65,534 host addresses. Therefore, the Internet Engineering Task Force (IETF) came up with an address assignment strategy called Classless Inter-Domain Router (CIDR, pronounced as "cider"). CIDR was a temporary measure that allowed organizations to use addressing schemes customized to their particular situation. An organization could receive four Class C network addresses with a custom subnet mask, as shown in Figure 3. The resulting network address is called a supernet because it consists of more than one classful network address. page 366

Line of Sight Wireless Internet

Line of sight wireless internet is an always-on service that uses radio signals for transmitting internet access, as shown in the figure. Radio signals are sent from a tower to the receiver that the customer connects to a computer or network device. A clear path between the transmission tower and customer is required. The tower may connect to other towers or directly to an internet backbone connection. The distance the radio signal can travel and still be strong enough to provide a clear signal depends on the frequency of the signal. Lower frequency of 900 MHz can travel up to 40 miles (65 km), while a higher frequency of 5.7 GHz can only travel 2 miles (3 km). Extreme weather conditions, trees, and tall buildings can affect signal strength and performance.

Satellite broadband

Provides network access to remote sites through the use of a directional satellite dish. The satellite dish transmits and receives signals to and from a satellite that relays these signals back to a service provider. Download speeds can reach up to 10Mb/s or more, while upload speed ranges about 1/10th of download speeds. It takes time for the signal from the satellite dish to relay to your ISP through the satellite orbiting the Earth. Due to this latency, it is difficult to use time-sensitive applications, such as video gaming, Voice over Internet Protocol (VoIP), and video conferencing.

Rule 2 of IPv6

Rule 2 - Omit All 0 Segments The second rule to help reduce the notation of IPv6 addresses is that a double colon (::) can replace any group of consecutive zeros. The double colon (::) can only be used once within an address, otherwise there would be more than one possible resulting address. page 367

subnet mask

Subnet masks are often displayed using prefix notation, as shown in Figure. The number after the "slash" indicates how many bits in the subnet mask are one bits. For example, the Class B network 172.16.0.0 with subnet mask of 255.255.0.0 would be written as 172.16.0.0/16. The "/16" indicates that the first 16 bits in the subnet mask are all ones. page 365

CSMA/CD (Carrier Sense Multiple Access/Collision Detection)

The Ethernet architecture is based on the IEEE 802.3 standard. The IEEE 802.3 standard specifies that a network implement the Carrier Sense Multiple Access with Collision Detection (CSMA/CD) access control method. In CSMA/CD, all devices listen to the network wire for clearance to send data. This process is similar to waiting to hear a dial tone on a phone before dialing a number. When the device detects that no other device is transmitting, the device can attempt to send data. If no other device sends any data at the same time, this transmission arrives at the destination computer with no problems. If another device transmits at the same time, a collision occurs on the wire. The first station that detects the collision sends out a jam signal that tells all stations to stop transmitting and to run a backoff algorithm. A backoff algorithm calculates random times in which the end station tries transmitting again. This random time is typically in 1 or 2 milliseconds (ms). This sequence occurs every time there is a collision on the network and can reduce Ethernet transmission by up to 40 percent. Note: Most Ethernet networks today are full duplex. In full duplex Ethernet, there is rarely a collision because devices can transmit and receive at the same time. page 341

IPv4 vs IPv6 formats

Today, it is common for a computer to have two versions of IP addresses. In the early 1990s there was a concern about running out of IPv4 network addresses. The Internet Engineering Task Force (IETF) began to look for a replacement. This led to the development of what is now known as IP version 6 (IPv6). Currently IPv6 is operating alongside and is beginning to replace IPv4. An IPv4 address is 32 bits long and is represented in dotted decimal. An IPv6 address is 128 bits long and is represented in hexadecimal. Figure 1 shows examples of IPv4 and IPv6 addresses. IP addressing is assigned by network administrators based on the location within the network. When a device moves from one network to another, its IP address will most likely change. Figure shows a topology with two LANs. This topology demonstrates that MAC addresses do not change when a device is moved. But IP addresses do change. Laptop was moved to LAN 2. Notice that Laptop's MAC address did not change, but its IP addresses did change. Show output for the command ipconfig /all on the laptop. The output shows the MAC address and two IP addresses. Note: Windows OS calls the NIC an Ethernet adapter and the MAC address a physical address. page 361

IPv4 address format

When a host is configured with an IPv4 address, it is entered in dotted decimal format, as shown in Figure 1. Imagine if you had to enter the 32-bit binary equivalent. The address 192.168.200.8 would be entered as 11000000101010001100100000001000. If just one bit were mistyped, the address would be different. The device then might not be able to communicate on the network. Each number separated by a period is called an octet because it represents 8 bits. Therefore, the address 192.168.200.8 has four octets. Each bit in an octet can be either a 1 (on) or a 0 (off). Also, each bit in an octet represents a value. The rightmost bit represents a 1. Each bit to its left is doubled, so that the leftmost bit represents 128. page 363

Physical Layer (Layer 1)

the physical layer or layer 1 is the first and lowest layer. This layer may be implemented by a PHY chip. ... The physical layer provides an electrical, mechanical, and procedural interface to the transmission medium. Responsible for movements of individual bits from one hop (node) to the next. page 338

DNS Server

translates the domain name into its associated IP address. To access a DNS server, a computer uses the IP address configured in the DNS settings of the NIC in the computer. DNS resolves or maps host names and URLs to IP addresses. All Windows computers contain a DNS cache that stores host names that have recently been resolved. The cache is the first place that the DNS client looks for host name resolution. Because it is a location in memory, the cache retrieves resolved IP addresses more quickly than using a DNS server and does not create network traffic. page 371

dynamic addressing

using DHCP to assign temporary IP addresses to a group of computers. If more than a few computers are a part of the LAN, manually configuring IP addresses for every host on the network can be time consuming and prone to errors. A DHCP server automatically assigns IP addresses, which simplifies the addressing process. Automatically configuring some of the TCP/IP parameters also reduces the possibility of assigning duplicate or invalid IP addresses. page 370

RFID (radio frequency identification)

RFID (radio frequency identification) uses a chip in a tag or label to store information, and information is transmitted from, or written to, the tag or label when the chip is exposed to the correct frequency of radio waves. RFID uses the frequencies within the 125 MHz to 960 MHz range to uniquely identify items, such as in a shipping department as shown in Figure 2. Active RFID tags that contain a battery can broadcast their ID up to 100 meters. Passive RFID tags rely on the RFID reader to use radio waves to activate and read the tag. Passive RFID tags are typically used for close scanning but have a range of up to 25 meters.

repeater

Regenerating weak signals is the primary purpose of a repeater, as shown in Figure 2. Repeaters are also called extenders because they extend the distance a signal can travel. In today's networks, repeaters are most often used to regenerate signals in fiber-optic cables. page 351

router

Routers connect networks, as shown in Figure. Switches use MAC addresses to forward traffic within a single network. Routers use IP addresses to forward traffic to other networks. A router can be a computer with special network software installed, or a device built by network equipment manufacturers. In larger networks, routers connect to switches, which then connect to LANs, like the router on the right in Figure. The router serves as the gateway to outside networks. The router on the left in Figure is also known as a multipurpose device or integrated router. It includes a switch and a wireless access point. For some networks, it is more convenient to purchase and configure one device that serves all your needs than to purchase a separate device for each function. This is especially true for the home or small office. Multipurpose devices may also include a modem. A device that forwards data packets between computer networks. page 322 & 346

server

Servers have software installed that enables them to provide services, such as files, email, or web pages, to clients. Each service requires separate server software. For example, the server in Figures 1 and 2 requires file server software to provide clients with the ability to retrieve and store files. A single server can run multiple types of server software. In a home or small business, it may be necessary for one computer to act as a file server, a web server, and an email server. A client computer can also run multiple types of client software. There must be client software for every service required. With multiple client software installed, a client can connect to multiple servers at the same time. For example, a user can check email and view a web page while instant messaging and listening to Internet radio. page 332

STP (Shielded twisted-pair cable)

Shielded twisted-pair (STP) was designed to provide better protection against EMI and RFI. As shown in Figure, each twisted-pair is wrapped in a foil shield. The four pairs are then wrapped together in a metallic braid or foil. page 354

MDF vs IDF

Short for main distribution frame, a cable rack that interconnects and manages the telecommunications wiring between itself and any number of IDFs. Unlike an IDF, which connects internal lines to the MDF, the MDF connects private or public lines coming into a building with the internal network. page 356

SC = subscriber connector fiber connectors

Sometimes referred to as square connector or standard connector. It is a widely adopted LAN and WAN connector that uses a push-pull mechanism to ensure positive insertions. This connector type is used with multimode and single-mode fiber. page 360

CAT 5 UTP

Speed 100 Mb/s at 100 MHz Manufactured with higher standard than Cat 3 to allow for higher data transfer rates.

CAT 5e UTP

Speed 1000 Mb/s at 100 MHz Manufactured with higher standard than Cat 5 to allow for higher data transfer rates. More twists per foot than Cat 5 to better prevent EMI and RFI from outside sources.

ST = straight tip fiber connectors

Straight-Tip ST fiber connectors = one of the first connector types used. The connector locks securely with a "twist-on/twist-off" bayonet style mechanism. page 359

EMI vs RFI

electromagnetic interference (EMI) or radio frequency interference (RFI). EMI and RFI can be caused by a variety of sources including electric motors and fluorescent lights. page 354

cladding of optical fiber

made from slightly different chemicals than those used to create the core. It tends to act like a mirror by reflecting light back into the core of the fiber. This keeps light in the core as it travels down the fiber. page 358

optical network cable media types

optical cables allow digital signals to be transmitted via pulses of light through either plastic or glass fibers.

ad hoc mode

Ad hoc means the WLAN is created when it is needed. Ad hoc is usually temporary. Figure shows an example ad hoc mode. The laptop is wirelessly connected to the smartphone, which has access to the Internet through cellular service provider. page 328

Bus network topology

Alternatively referred to as a line topology, a bus topology is a network setup in which each computer and network device are connected to a single cable or backbone. Depending on the type of network card used in each computer of the bus topology, a coaxial cable or an RJ-45 network cable is used to connect them together. Advantages of bus topology It works well when you have a small network. It's the easiest network topology for connecting computers or peripherals in a linear fashion. It requires less cable length than a star topology. Disadvantages of bus topology It can be difficult to identify the problems if the whole network goes down. It can be hard to troubleshoot individual device issues. Bus topology is not great for large networks. Terminators are required for both ends of the main cable. Additional devices slow the network down. If a main cable is damaged, the network fails or splits into two.

Optical Cable

An optical fiber cable, also known as a fiber optic cable, is an assembly similar to an electrical cable, but containing one or more optical fibers that are used to carry light. The glass or plastic optical fiber elements are typically individually coated with plastic layers and contained in a protective tube suitable for the environment where the cable will be deployed. Because it uses light to transmit signals, fiber-optic cable is not affected by EMI or RFI. All signals are converted to light pulses as they enter the cable, and converted back into electrical signals when they leave it. This means that fiber-optic cable can deliver signals that are clearer, can go farther, and have greater bandwidth than cable made of copper or other metals. Although the optical fiber is very thin and susceptible to sharp bends, the properties of the core and cladding make it very strong. Optical fiber is durable and is deployed in harsh environmental conditions in networks all around the world. Different types of cable are used for different applications, for example long distance telecommunication, or providing a high-speed data connection between different parts of a building. page 358

host device

Any device that sends and receives information on the network such as desktops, laptops, servers, tablets, smartphones, printers, cameras, scanners, etc. page 321

twisted-pair cable

Cables made of copper wires that are twisted around each other and are surrounded by a plastic jacket (such as traditional home phone wire and most Ethernet networks). page 352

straight through vs crossover TP

Crossover cables are usually used to connect the same type of devices and may be a little harder to find since they aren't used nearly as much as straight-through cables. A crossover cable can be used to: 1) Connect 2 computers directly. ... That is to say, the two end of the crossover Ethernet cable are wired differently. Note: If the incorrect cable type is used, the connection between network devices will not function. However, many newer devices can automatically sense which pins are used for transmit and receive and will adjust their internal connections accordingly. page 355 & 357

Ring Topology Pros & Cons

Pros & Cons of Ring Topology noted in illustration.

Z-Wave

Z-Wave technology is a proprietary standard that is now owned by Silicon Labs. However, a public version of the interoperability layer of Z-Wave was open sourced in 2016. These open source Z-Wave standards include Z-Wave's S2 security, Z/IP for transporting Z-Wave signals over IP networks, and Z-Ware middleware. Z-Wave operates within a variety of frequencies based on the country from 865.2 MHz in India to 922 - 926 MHz in Japan. Z-Wave operates at 908.42 MHz in the North America. Z-Wave can transmit data up to 100 meters but has a slower data rate than Zigbee at 9.6-100 kb/s. Z-Wave can support up to 232 devices in one wireless mesh network. Search the internet for "Zigbee and Z-Wave" to learn the latest information about these two smart home standards.

bits vs bytes

Bit (0's and 1's) = binary digit Byte (character) 1 byte is made up of 8 bits page 325

peer-to-peer (P2P) disadvantages

peer-to-peer networks have several disadvantages: There is no centralized network administration, which makes it difficult to determine who controls resources on the network. There is no centralized security. Each computer must use separate security measures for data protection. The network becomes more complex and difficult to manage as the number of computers on the network increases. There might not be any centralized data storage. Separate data backups must be maintained. This responsibility falls on the individual users. page 330

5G

5G is the fifth generation of wireless data networks and an upgrade that you will want sooner or later, depending on your appetite for wireless bugs and growing pains. It is much more than the simple bandwidth or "speed" improvement on your phone that you're used to from the history of 4G and 3G before it. 5G boasts low latency, intelligent power consumption, high density and network slicing -- attributes that make it a breakthrough.

LTE (Long Term Evolution)

A 4G cellular network technology that achieves downlink data rates of up to 1 Gbps and uplink rates up to 500 Mbps. AT&T and Verizon have adopted LTE for their high-speed wireless data networks.

Bluetooth

A Bluetooth device can connect up to seven other Bluetooth devices, as shown in Figure 1. Described in the IEEE standard 802.15.1, Bluetooth devices operate in the 2.4 to 2.485 GHz radio frequency range and is typically used for PANs. The Bluetooth standard incorporates Adaptive Frequency Hopping (AFH). AFH allows signals to "hop" around using different frequencies within the 2.4 to 2.485 GHz range, thereby reducing the chance of interference when multiple Bluetooth devices are present.

network media

A general term for all forms of pathways that support network communication. - Copper cabling - Uses electrical signals to transmit data between devices, - Fiber-optic cabling - Uses glass or plastic fiber to carry information as light pulses. -Wireless connection - Uses radio signals, infrared technology, laser beam or satellite transmissions. page 323

Mesh Network Topology

A network setup where each computer and network device is interconnected with one another, allowing for most transmissions to be distributed even if one of the connections go down. It is a topology commonly used for wireless networks. Image result for mesh network topology advantages and disadvantages Disadvantages of a mesh topology. The cost to implement is higher than other network topologies, making it a less desirable option. Building and maintaining the topology is difficult and time consuming. The chance of redundant connections is high, which adds to the high costs and potential for reduced efficiency.

client/server network

A network that uses centrally administered computers, known as servers, to enable resource sharing for and to facilitate communication between the other computers on the network. In a client-server network, the client requests information or services from the server. The server provides the requested information or service to the client. Servers on a client-server network commonly perform some of the processing work for client machines. For example, a server can sort through a database before delivering the records requested by the client. In a client-server network, resources are controlled by a centralized network administration. The network administrator implements data backups and security measures. The network administrator also controls user access to the server resources. page 331

patch panels

A patch panel is commonly used as a place to collect incoming cable runs from the various networking devices throughout a facility, as shown in Figure 1. It provides a connection point between PCs and the switches or routers. A patch panel can be unpowered or powered. A powered patch panel can regenerate weak signals before sending them on to the next device. Provides a physical cross connect point for devices.

switch

A switch does not Broadcast! so, network traffic is reduced! A switch microsegments a LAN. Switches has intelligence by maintaining a switching table. A switch is used to connect multiple devices to the network. page 322 & 347

Full-duplex transmission

A type of data transmission in which data can move in both directions at the same time. When data flows in both directions at the same time it is known as full-duplex, as shown in the figure. A telephone conversation is an example of full-duplex communication. Both people can talk and be heard at the same time. Full-duplex networking technology increases network performance because data can be sent and received at the same time. Broadband technologies, such as digital subscriber line (DSL) and cable, operate in full-duplex mode. Broadband technology allows multiple signals to travel on the same wire simultaneously. With a DSL connection, for example, users can download data to the computer and talk on the telephone at the same time. page 326

Simplex transmission

A type of data transmission in which data travels in a single direction only. An example of simplex transmission is the signal that is sent from a TV station to your home TV. page 325

UTP (Unshielded Twisted Pair)

A type of twisted pair cabling that does not include shielding around its conductors. UTP cable consists of four pairs of color-coded wires that have been twisted together and then encased in a flexible plastic sheath that protects from minor physical damage. The twisting of wires helps protect against crosstalk. However, UTP does not protect against EMI or RFI. There is also a thin nylon cord within the cable which, when pulled backward along the length of the cable, will slice the jacket. This is the preferred method to access the wire pairs. It prevents nicking or cutting any of the wires in the cable. page 353

Activity = wireless protocols

Activity = wireless protocols

RJ-45 connector

An eight-position connector that uses all four pairs of wires. It is usually used for network connectivity. Both UTP and STP cables are terminated with an RJ-45 connector and plug into RJ-45 sockets, as shown in Figure 3. Compared to UTP cable, STP cable is significantly more expensive and difficult to install. To gain the full benefit of the shielding, STP cables are terminated with special shielded STP RJ-45 data connectors (not shown). If the cable is improperly grounded, the shield may act as an antenna and pick up unwanted signals. page 355

hardware firewall

An integrated router also serves as a hardware firewall. Hardware firewalls protect data and equipment on a network from unauthorized access. A hardware firewall resides between two or more networks, as shown in the figure. It does not use the resources of the computers it is protecting, so there is no impact on processing performance. page 349

fiber optic cable 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. Because light can only travel in one direction over optical fiber, two fibers are 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. page 359

bandwidth

Bandwidth on a network is like a highway. The number of lanes on the highway represents the amount of cars that could travel on the highway at the same time. An eight-lane highway can handle four times the number of cars that a two-lane highway can hold. In the highway example, the cars and trucks represent the data. page 325

Bluetooth technology

Bluetooth is a wireless technology that enables devices to communicate over short distances. A Bluetooth device can connect up to SEVEN other Bluetooth devices. Described in the IEEE standard 802.15.1, Bluetooth devices are capable of handling voice and data. Bluetooth devices operate in the 2.4 to 2.485 GHz radio frequency range, which is in the Industrial, Scientific, and Medical (ISM) band. page 328

bridges vs switches

Bridges were introduced to divide LANs into segments. Bridges keep a record of all the devices on each segment. A bridge can then filter network traffic between LAN segments. This helps reduce the amount of traffic between devices. For example, in Figure, if PC-A needs to send a job to the printer, the traffic will not be forward to Segment 2. However, the server will also receive this print job traffic. Bridges and hubs are now considered legacy devices because of the benefits and low cost of switches. page 346

Plenum vs riser-rated cabling

Cable which is to be run between floors in non-plenum areas is rated as RISER cable. The fire requirements on riser cable are not as strict. Thus, plenum cable can always replace riser cable, but riser cable cannot replace plenum cable in plenum spaces. A special type of cabling with a fire-retardant jacket placed inside the "plenum" space between structural floor and dropped ceiling or inside walls. page 356

CAN

Campus Area Network: a geographic network that covers a geographic area such as a business park, college campus or university.

coaxial cables

Coaxial cable (or coax) carries data in the form of electrical signals. It provides improved shielding compared to unshielded twisted-pair (UTP), so it has a higher signal-to-noise ratio and can therefore carry more data. Coaxial cable has no specific maximum bandwidth. The type of signaling technology used determines the speed and limiting factors. Wired medium, initially used for cable TV or satellite, consisting of a single inner conductor wire (typically copper or aluminum) surrounded by insulation, which is then surrounded by a mesh-like conductor. page 351

Access Control List (ACL)

Firewalls use various techniques for determining what is permitted or denied access to a network segment, such as an Access Control List (ACL). This list is a file that the router uses which contains rules about data traffic between networks. Considerations when selecting a hardware firewall include: Space - Free standing and uses dedicated hardware Cost - Initial cost of hardware and software updates can be costly Number of computers - Multiple computers can be protected Performance requirements - Little impact on computer performance Note: On a secure network, if computer performance is not an issue, enable the internal operating system firewall for additional security. Some applications might not operate properly unless the firewall is configured correctly for them. page 349

HAN

Home Area Network small network typically used in home or small home offices. Connects via Bluetooth, WiFi, Ethernet. A home area network (HAN) is a network that connects devices, such as mice, keyboards, printers, smartphone, and tablets within the range of an individual person. All of these devices are dedicated to a single host and are most often connected with Bluetooth and WiFi technology. page 328

Dual Ring Topology

Pros & Cons of Dual Ring Topology noted in illustration.

Hubs vs Switches

Hubs, shown in Figure, receive data on one port and then send it out to all other ports = "BROADCASTs". A hub extends the reach of a network because it regenerates the electrical signal. Hubs can also connect to another networking device, such as a switch or router, which connects to other sections of the network. Hubs are used less often today because of the effectiveness and low cost of switches. Hubs do not segment network traffic. When one device sends traffic, the hub floods that traffic to all other devices connected to hub. The devices are sharing the bandwidth. Bridges and hubs are now considered legacy devices because of the benefits and low cost of switches. page 346

Peer-to-Peer Network (P2P)

In a peer-to-peer network, there is no hierarchy among the computers, nor are there any dedicated servers. Each device, also called a client, has equivalent capabilities and responsibilities. Individual users are responsible for their own resources and can decide which data and devices to share or install. Because individual users are responsible for the resources on their own computers, the network has no central point of control or administration. Peer-to-peer networks work best in environments with ten or fewer computers. Peer-to-peer networks can also exist inside larger networks. Even on a large client network, users can still share resources directly with other users without using a network server. In your home, if you have more than one computer, you can set up a peer-to-peer network. You can share files with other computers, send messages between computers, and print documents to a shared printer. page 330

infrastructure mode of WLAN

In infrastructure mode, wireless clients connect to a wireless router or access point (AP). The AP in Figure 1 is connected to a switch, which provides access to the rest of the network and to the Internet. Access points are typically connected to the network using copper cabling. Instead of providing copper cabling to every network host, only the wireless access point is connected to the network with copper cabling. The range (radius of coverage) for typical WLAN systems varies from under 98.4 ft (30 m) indoors to much greater distances outdoors, depending on the technology used. page 327

IP phone

Internet Protocol phone, which is known as an IP phone, connects to a computer network instead of the traditional telephone network. page 321

buffer of optical fiber

Is used to help shield the core and cladding from damage. page 358

LAN

Local Area Network; a geographic network that covers a relatively small geographic area such as a room, floor, building or adjacent buildings. Traditionally, a LAN is defined as a network that encompasses a small geographical area. However, the distinguishing characteristic for LANs today is that they are typically owned by an individual, such as in a home or small business, or wholly managed by an IT department, such as in a school or corporation. This individual or group enforces the security and access control policies of the network. page 326

LC = Lucent connector fiber connectors

Lucent Connector simplex connectors are a smaller version of the fiber-optic SC connector. It is sometimes called a little or local connector and is quickly growing in popularity due to its smaller size. page 360

MAN

Metropolitan Area Network; a geographic network that covers a larger geographic area such as a city or community; may be used to connect computers in libraries, government agencies, etc. together - typically no more than 30 miles in size. A metropolitan area network (MAN) is a network that spans across a city. The network consists of various buildings interconnected through wireless or fiber optic backbones. The communication links and equipment are typically owned by a consortium of users, or by a network service provider who sells the service to the users. A MAN can act as a high-speed network to enable sharing of regional resources. page 329

switch microsegmenting

Microsegmenting means that switches filter and segment network traffic by sending data only to the device to which it is sent. This provides higher dedicated bandwidth to each device on the network. If there is only one device attached to each port on a switch it operates in Full-Duplex mode. This is not the case with a hub. When PC-A sends a job to the printer, only the printer receives the traffic. page 346

multi-mode fiber (MMF)

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 Figure 2. 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. page 359

NFC (Near Field Communication)

NFC uses frequency 13.56 MHz and is a subset of the RFID standards. NFC is designed to be a secure method to complete transactions. For example, a consumer pays for good or services by waving the phone near the payment system. Based on a unique ID, the payment is charged directly against a pre-paid account or bank account. NFC is also used in mass-transportation services, the public parking sector, and many more consumer areas.

MDF (Main Distribution Facility or Frame)

New or renovated office buildings often have some type of UTP cabling that connects every office to a central point called the Main Distribution Facility (MDF). The distance limitation of UTP cabling used for data is 100 meters (330 feet). Cable runs in excess of this distance limitation need a switch, repeater, or hub to extend the connection to the MDF. These switches, repeaters, and hubs would be located in an IDF (Independent Distribution Facility). A Main Distribution Frame (MDF) is a signal distribution frame or cable rack used in telephony to interconnect and manage telecommunication wiring between itself and any number of intermediate distribution frames and cabling from the telephony network it supports. page 356

shared resources

On a network, resources such as hardware, software, and data, made available for authorized users to share. page 322

Activity = Network Types

PAN-LAN-MAN-WAN-WLAN etc

Activity = CISCO Packet Tracer = Cable a Network

Packet Tracer is a cross-platform visual simulation tool designed by Cisco Systems that allows users to create network topologies and imitate modern computer networks. The software allows users to simulate the configuration of Cisco routers and switches using a simulated command line interface. page 358

PAN

Personal Area Network: small network typically used in the space of a vehicle. Connects via Bluetooth. A personal area network (PAN) is a network that connects devices, such as microphones, headsets, visor clip-on speakerphones, smartphone, and tablets within the reach of the driver. All of these devices are dedicated to a single host and are most often connected with Bluetooth technology. page 328

PoE (Power over Ethernet)

Power over Ethernet (PoE) is a technology for wired Ethernet local area networks (LANs) that allows the electrical current necessary for the operation of each device to be carried by the data cables rather than by power cords. A PoE switch transfers small amounts of DC current over an Ethernet cable, along with the data, to power PoE devices. Low voltage devices that support PoE, such as Wi-Fi access points, surveillance video devices, and IP phones, can be powered from remote locations. Devices that support PoE can receive power over an Ethernet connection at distances up to 330 ft (100 m) away. Power can also be inserted in the middle of a cable run using a PoE injector. A method of delivering current, usually 15.4 watts, to devices using Ethernet connection cables. page 351

Activity = T-568A Pinouts

T568A and T568B are the two color codes used for wiring eight-position RJ45 modular plugs. Both are allowed under the ANSI/TIA/EIA wiring standards. The only difference between the two color codes is that the orange and green pairs are interchanged. T568A wiring pattern is recognized as the preferred wiring pattern for this standard because it provides backward compatibility to both one pair and two pair USOC wiring schemes. The T568B standard matches the older ATA&T 258A color code and is/was(?) the most widely used wiring scheme. It is also permitted by the ANSI/TIA/EIA standard, but it provides only a single pair backward compatibility to the USOC wiring scheme. The U.S. Government requires the use of the preferred T568A standard for wiring done under federal contracts. page 358

switching table

The switching table contains a list of all MAC addresses on the network, and a list of which switch port can be used to reach a device with a given MAC address. The switching table records MAC addresses by inspecting the source MAC address of every incoming frame, as well as the port on which the frame arrives. The switch then creates a switching table that maps MAC addresses to outgoing ports. When traffic arrives that is destined for a particular MAC address, the switch uses the switching table to determine which port to use to reach the MAC address. The traffic is forwarded from the port to the destination. By sending traffic out of only one port to the destination, other ports are not affected. page 346

coaxial cable types

Thicknet or 10BASE5 - Used in networks and operated at 10 Mb/s with a maximum length of 1640.4 ft. (500 m.) Thinnet 10BASE2 - Used in networks and operated at 10 Mb/s with a maximum length of 607 ft. (185 m.) RG-59 - Most commonly used for cable television in the United States RG-6 - Higher quality cable than RG-59, with more bandwidth and less susceptibility to interference. page 353

latency

Time it takes for a bit to travel from its sender to its receiver. The amount of time it takes data to travel from source to destination is called latency. Like a car traveling across town that encounters stop lights or detours, data is delayed by network devices and cable length. Network devices add latency when processing and forwarding data. When surfing the Web or downloading a file, latency does not normally cause problems. Time critical applications, such as Internet telephone calls, video, and gaming, can be significantly affected by latency. page 325

Categories of Twisted Pair Cable

Twisted-pair cables come in several categories (Cat). These categories are based on the number of wires in the cable and the number of twists in those wires. Most networks today are wired using twisted-pair cabling. The characteristics of twisted-pair cable are shown in Figure. page 356

UTM

Unified Threat Management (UTM) is a generic name for an all-in-one security appliance. UTMs include all the functionality of an IDS/IPS as well as stateful firewall services. Stateful firewalls provide stateful packet filtering by using connection information maintained in a state table. A stateful firewall tracks each connection by logging the source and destination addresses, as well as source and destination port numbers. In addition to IDS/IPS and stateful firewall services, UTMs also typically provide additional security services such as: Zero Day protection Denial of Service (DoS) and Distributed Denial of Service (DDoS) protection Proxy filtering of applications Email filtering for spam and phishing attacks Antispyware Network access control VPN services These features can vary significantly, depending on the UTM vendor. In the firewall market today, UTMs are now typically called next-generation firewalls. For example, the Cisco Adaptive Security Appliance in the figure offers the latest in next-generation firewall features.

VLAN

Virtual Local Area Network allow administrator to segment ports on a single switch as if it were multiple switches. This provides more efficient forwarding of data by isolating traffic to only those ports where it is required. VLANs also allow end devices to be grouped together for administrative purposes.

packets

When data is sent over a computer network, it is broken up into small chunks called packets. Each packet contains source and destination address information. Packets are sent across a network one bit at a time. Bandwidth is measured in the number of bits that can be sent every second. The following are examples of bandwidth measurements: b/s - bits per second kb/s - kilobits per second Mb/s - megabits per second Gb/s - gigabits per second. page 325

wireless access point (WAP)

Wireless access points, shown in Figure, provide network access to wireless devices, such as laptops and tablets. The wireless access point uses radio waves to communicate with the wireless NIC in the devices and other wireless access points. An access point has a limited range of coverage. Large networks require several access points to provide adequate wireless coverage. A wireless access point provides connectivity only to the network, while a wireless router provides additional features. An access point (AP) provides wireless connectivity, but has fewer features than a wireless router. page 323

Zigbee

Zigbee uses low-power digital radios based on the IEEE 802.15.4 wireless standard for low-rate wireless personal area networks (LR-WPANs) that is meant to be used by low-cost, low-speed devices. Zigbee operates within frequencies from 868 MHz to 2.4 GHz and is limited to 10 to 20 meters. Zigbee has a data rate from 40-250 kb/s and can support approximately 65,000 devices. The ZigBee specification relies on a main device called a ZigBee Coordinator. Tasked with managing all ZigBee client devices, the ZigBee Coordinator is responsible for the creation and maintenance of the ZigBee network.

WLAN (Wireless Local Area Network)

a LAN communication technology in which radio, microwave or infrared links take the place of physical cables. A Wireless LAN (WLAN) is a LAN that uses radio waves to transmit data between wireless devices. In a traditional LAN, devices are connected together using copper cabling. In some environments, installing copper cabling might not be practical, desirable, or even possible. In these situations, wireless devices are used to transmit and receive data using radio waves. As with LANs, on a WLAN, you can share resources, such as files, printers, and Internet access. page 327

Star Network Topology

all devices on the network connect to a central device, and this central device creates a single point of failure on the network. Disadvantages of a Star Topology: Requires more cable length than a linear topology. If the hub, switch, or concentrator fails, nodes attached are disabled. More expensive than linear bus topologies because of the cost of the hubs, etc.

protocols

rules of computer communications. Internet protocols are sets of rules governing communication between computers on a network. Protocol specifications define the format of the messages that are exchanged. Timing is crucial for the reliable delivery of packets. Protocols require messages to arrive within certain time intervals so that computers do not wait indefinitely for messages that might have been lost. Systems maintain one or more timers during the transmission of data. Protocols also initiate alternative actions if the network does not meet the timing rules. page 320 & 334

Half-duplex transmission

sending data in both directions but only one direction at a time. With half-duplex, the channel of communications allows alternating transmission in two directions, but not in both directions simultaneously. Two-way radios, such as police or emergency communications mobile radios, work with half-duplex transmissions. When you press the button on the microphone to transmit, you cannot hear the person on the other end. If people at both ends try to talk at the same time, neither transmission gets through. page 325

duplex multimode LC connectors

similar to LC simplex connector, but using a duplex connector. page 360

strengthening material of optical fiber

surrounds the buffer, prevents the fiber cable from being stretched when it is being pulled. The material used is often the same material used to produce KEVLAR bulletproof vests. page 358

core of optical fiber

the core is actually the light transmission element at the center of the optical fiber. This core is typically silica or glass. Light pulses travel through the fiber core. page 358

Ring Network Topology

the network is configured in the shape of a circle with each node connecting to the next node. Messages travel around the circle in one direction. Disadvantages of ring topology: All data being transferred over the network must pass through each workstation on the network, which can make it slower than a star topology. The entire network will be impacted if one workstation shuts down.

jacket of optical fiber

typically a PVC jacket that protects the fiber against abrasion, moisture, and other contaminants. This outer jacket composition can vary depending on the cable usage. page 358

wireless network media types

wireless network media falls into two categories: 1. direct line of sight data transmission includes a. infrared beam of light b. laser beam of light 2. not direct line of sight transmission includes a. WiFi b. Bluetooth c radio waves