Data communications and Lans Modules 1-3 study guide
Explain the difference between a LAN and a WAN.
LAN provides access over smaller area WAN provides access to other networks over a wider area.
Describe the following communication types: a. Unicast b. Multicast c. Broadcast D, Anycast
a. Unicast Information is transmitted to a single end device b. Multicast Information is being transmitted to multiple end devices c. Broadcast information is being transmitted to all end devices d. Anycast is an IPv6 term and is the sending of data in a one-to-nearest communication.
Explain the following components of a router: a. Flash b. RAM c. ROM d. NVRAM e. Console f. Interface
a. operating system of the router itself. The contents in the flash memory remain even after reboot or shutdown. b. Stores routing tables and file configuration while router is powered on. c. stores the bootstrap program and basic OS software. d. It stores the "startup-config" file. The contents in the NVRAM remain even after the router is shutdown or rebooted. e. Console port is a port to connect a computer directly to a router or switch. f. what ****ing interface you stupid ****. There's like a thousand interfaces. Listed on google for router interface? Do you mean the interface where I plug the Ethernet cable in? Or the user interface. You stupid lazy bitch.
Explain the terms shell, kernel, and hardware as related to computer systems.
a. shell is a user interface for access to an operating system's services. b.The kernel provisions hardware resources to meet software requirements c. physical components of the system that physical process data.
What are the functions of intermediary devices on a network?
direct path of the data connect individual hosts to the network
What command enables an interface (makes it active)?
enter
What are some considerations before upgrading an IOS on a Cisco device?
manufacturer support, compatibility, infrastructure, application bug fixes, and features and functionalities.
What are the functions of end devices on a network?
originate the data that flows through the network interface between humans and the communication network
What device provides for best path selection in a network?
router
What is the ping command? Why do we use it?
to verify the connectivity of your confirguration
Identify characteristics of circuit-switched network.
A dedicated connection is formed on a single line and no routing decisions are made. Remains connected until users terminate the connection. Outdated.
What is a client/server network?
A medium through which clients access resources and services from a central computer.
What is meant by the term "converged network?"
A network capable of delivering data voice and video between many different types of devices on the same network.
What is a peer-to-peer network?
A network where a computer can run as both client and server to share data to other users on the network.
What is the difference between an open standards and a proprietary standard? What are the benefits of using open standards?
A proprietary standard is owned by one company and they exercise sole discretion as to who may use it and under what terms An open standard is a standard that is publicly available and people may use it as they wish. Open standards are easily accessible to average users and can be upgraded by the public.
What is "cloud" computing?
A way in which we access and store data offloaded into remote locations
Briefly describe the following standards (to be discussed in more detail later): a. IEEE 802.3 b. IEEE 802.5 c. IEEE 802.11 d. EIA/TIA 568a
A. IEEE 802.3 is a set of standards and protocols that define Ethernet-based networks B. The IEEE 802.5 outdated standard specifies the characteristics for Token Ring networks. before Ethernet C. IEEE 802.11 refers to the set of standards that define communication for wireless LANs D. TIA/EIA-568-A-1995 (Commercial Building Telecommunications Wiring Standards) Defines a standard for building cable system
Define the following internet connectivity solutions: a. cellular b. DSL c. satellite d. cable e. dial-up telephone leased line
A. Internet access through cell towers using cell phone networks. Limited by capabilities of phone and tower. b.Internet access through Digital Subscriber Lines is a high bandwidth, connection that runs over a telephone line. High bandwidth. High availability c.Internet access through satellite disks Low bandwidth high availability. D. Internet access through television cable lines. High bandwidth. High availability E.Internet access through phone line, Low bandwidth high availability. F. Internet access through leased line. A private circuit rented at high cost. High bandwidth. Low availability.
Explain what is meant by context-sensitive help on a Cisco device.
Allows users to quickly find answers by using ? on the command line and a appropriate answer is given back.
What security solutions are available to network administrators? Describe three.
Antivirus protects end devices from becoming infected. Firewall blocks unauthorized access into the network Access Control list filter traffic based on IP addresses VPN secures network connection
What is a PDU? What are the names of the PDUs for each layer of the OSI model? (protocol data unit)
Application PDU -Data Transport layer PDU - Segment Network layer PDU- Packet Data Link PDU- Frame Physical layer PDU- Bits
What is the benefit of using a layered model?
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
Explain DHCP. How does it benefit a network?
DHCP automatically enables IPv4 address configuration for every device DHCP-enabled. If this did not exist every device would need manually add Gateway, DNS server, IPV4 address, Subnetmask.
Explain the encapsulation process from Application layer to Physical Layer.
Data is segmented from the application layer into smaller unites for transmission over the network. It's then sequenced to assure reassembly and correct destination arrival. Application data is passed down the protocol stack for correct formatting forming protocol data units, enabling it to cross network media
What interfaces and modes can be password protected on a cisco router?
EXEC mode and Priv. EXEC mode
Identify characteristics of packet-switched network.
Every packet of data can take it's own route on multiple channels. It's faster and dynamic. The data after taking multiple routes reassembles itself.
What is the purpose of "flow control?"
Flow control defines how much information can be sent and wehat speed it can be delivered.
Identify three primary standards organizations used in Networking.
Iana: responsible for overseeing and managing IP address allocation Internet soceity (ISOC)- Responsible for promoting open development and evolution of internet use around the world. IRTF- focused on long term reserached related to internet and TCP/IP proticals.
What type of network must a home user access in order to do online shopping?
Wireless LAN
Which device performs the function of determining the path that messages should take through internetworks?
a router
What are the criteria used to select network media?
1.the distance the media can successfully carry a signal 2.The environment where the media is to be installed
Explain the seven layers of the OSI Model.
Physical (layer1): The physical layer provides the means to transport bits across network media. Addresses the function of physical components encoding signaling. Encoding is converting data bits to code to be interpreted. Signaling is the method is the way bits are represented. Ex the charge or optical pulse of the signal. Data Link (layer2) : Prepares data for physical transport (ex. NIC). In this way it controls how data is placed and received (IPV4 and 6). It sends data to layer 3 packets to proper upper layer protocols. Network(layer3): Provides services to allow end devices to exchange data across networks. IPv4 and 6 are network layer communication protocols. Network layer protocols function to enable end to end communications, such as addressing end devices for identification on network, Encapsulation adds ip header information to the data being sent by the transport layer, Routing provides the service of directing packets to a destination host, De-encapsulation checks the IP header and sends it to transport layer for destination Transport (layer4) Generate data that must be exchanged between source and destination host. Responsible for logical communication between hosts. Session(layer5) The session layer provides services to the presentation layer to organize its dialogue and to manage data exchange. Presentation(layer6) The presentation layer provides for common representation of the data transferred between application layer services. Application(layer7) The application layer contains protocols used for process-to-process communications.
Define QoS
Quality of service in reference to the manner of managing congestion on a network and insuring the quality of content delivery to all it's users (no buffering)
A problem occurs when making a change to the configuration file on a router. If the config changes were not saved, what can be done to reverse the changes made?
Remove the commands or reload the device under priv. EXEC mode command restore startup-config
What are the 3 methods you can use to verify a banner message on a Cisco device?
Show run data, Exit command to start interface then relog back in, Command Show Banner motd in config mode.
What command allows you to encrypt the console and vty passwords?
Sw-Floor-1(config)# enable secret class
What are the commands for configuring a proper hostname on a device?
Switch# configure terminal Switch (config)# hostname Sw-Floor-1 Sw-Floor-1(config)#
Explain the different hotkeys and shortcuts used when configuring a Cisco router or switch.
Tab completes a partial entry. Ctrl+K deletes all commands from the cursor onward Ctrl+E moves the cursor to the end of the line Ctrl+A moves the to the end of the line
Define the term telepresence.
Telepresence refers to a set of technologies which allow a person to feel as if they were present
Explain the difference between Telnet and SSH? Which is more secure?
Telnet: Insecure in-band method of establishing a CLI session through virtual interface. Secure shell (SSH): In-band method for remotely establkishing a secure CLI connection through a virtual interface over a network.
What are the differences and similarities between the OSI and the TCP/IP models?
They are both models that describe the transfer of data between end devices and other machines. They are similar in that they both break the system down into an application, transport, network and physical layer. However the models differed in that extra layers of the OSI model are condensed into other layers.
Why would you place an IP address and gateway address on a Layer 2 switch?
To access the network remotely via the internet.
Why do you configure hostnames?
To identify a specific device on the network
What connection is required for an initial configuration of Cisco 2960 switch
Use the console port to locally access the switch from a serial or USB interface of the PC.
What are the different configuration modes (prompts) on a router/switch?
User EXEC mode limited capabilities but useful for basic operations. Monitoring commands mostly. Privileged EXEC mode to execute configuration commands
What is a virtual interface on Cisco Switch? Explain.
Virtual interfaces allow you to removely manage the switch over a network using IPv4 and 6.
Identify five network security threats.
Viruses, Spyware, DOSS (denial of service), Identity theft, Data theft.
