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Introduction to Cisco Router Configuration

Chapter 1 - The Internetworking Model

Objectives

Upon completion of this chapter, you will be able to:

• Discuss the major influences of user requirements on network evolution.
• Identify at least three reasons why the industry uses a layered network model.
• Identify the functions of each layer of the ISO/OSI reference model.
• Define and explain the five conversion steps of data encapsulation.

Summary

• Internetworking evolves to support current and future applications.
• The OSI reference model organizes network functions into seven categories called layers.
• Data flows from upper-level user applications to lower-layer bit stransmitted over network media.
• Peer-to-peer functions use encapsulation and de-encapsulation at layer interfaces.
• Most network manager tasks configure the lower three layers.

Excercise

Problem 1

Objective: Identify at least three reasons why the industry uses a layered network model.
Write at least three reasons why the industry uses a layered network model.

1. _______
2. _______
3. _______

Problem 2

Objective: Identify the functions of each layer of the ISO/OSI reference model.
As your instructor reads a layer's function in the ISO/OSI reference mode, write that layer's name in the appropriate numbered box in the seven-layer rectangle below:

Problem 3

Objective: Define and explain the five conversion steps of data encapsulation.
When a user's information is converted into hits that hardware can use, five conversion steps can occur. Write these five steps on the line provided below; include a brief description of what occurs during each conversion step. The first and last steps are provided as your reference.

1. User information is converted to _______
2. _______ is converted to _______
3. _______ are converted to _______
4. _______ are converted to _______
5. _______ are converted to bits.

Solutions

Chapter 2 - Applications and Upper Layers

Objectives

Upon completion of this chapter, you will be able to:

• Name and describe computer, network, and internetwork applications.
• Decribe the OSI presentation functions and identify common standards.
• Describe the OSI session functions and identify common standards.
• Describe the OSI transport functions for end-to-end network services.
• Identify common processes for establishing connections, flow control, and windowing.

Summary

• The ISO/OSI reference model describes network applications.
• Presentation layer formats and converts network application data to represent text, graphics, images, video, and audio.
• Session-layer functions coordinate communication interactions between applications.
• Reliable transport-layer functions include
  • Multiplexing
  • Connection synchronization
  • Flow control
  • Error recovery
  • Reliability through windowing

Exercise

Problem 1

Objective: Name and describe computer, network, and internetwork applications.
Early in this chapter, the presentation distinguished between various applications types. Write three examples of network applications and three examples of internetworking applications; include a brief description of what each application does.

1. Network Applications:
   _______
   
2. Internetworking Applications:
   _______

Problem 2

Objective: Describe the OSI presentation functions and identify common standards.
Write a description of the OSI presentation-layer functions. Then write the names of at least two presentation-layer standards or types.

_______

Problem 3

Objective: Describe the OSI session functions and identify common standards.
Write a description of the OSI session-layer functions. Then write the names of at least two session-layer standards.

_______

Problem 4

Objective: Describe the OSI transport functions for end-to-end network services.
The transport function in the ISO/OSI reference model extends services across some portion of the topology shown below. Circle the letter of the brace that indicated the correct extent of transport services.

Problem 5

Objective: Identify common processes for establishing connections, flow control, and windowing.

1. Telnet and FTP can share a Layer 4 connection. What process allows this?
   _______
   
2. Data can be lost if a host on one side is allowed to send so many segments that the other-side host overflows its buffers. Write the name of the generic process used to avoid this problem.
   _______
   
3. TCP enables reliability by using windowing. List two mechanisms that work with windowing to help ensure delivery of segments without duplication and data loss.
   _______

Solutions

Chapter 3 - Physical and Data Link Layers

Objectives

Upon completion of this chapter, you will be able to:

• Identify and describe the data link sublayers and their functions.
• Explain the use of MAC addresses.
• Describe the topology and functionality of LANs.
• Differentiate between LAN and WAN protocols.
• Describe the characteristics of WAN-based protocols.

Summary

• The ISO/OSI reference model describes network applications.
• Presentation layer formats and converts network application data to represent text, graphics, images, video, and audio.
• Session-layer functions coordinate communication interactions between applications.
• Reliable transport-layer functions include
  • Multiplexing
  • Connection synchronization
  • Flow control
  • Error recovery
  • Reliability through windowing

Exercise: MAC Addresses

Objective: Explain the use of MAC addresses.
Complete the table to show what address each device would have for another device.

Host A addresses:

• for host B ....
• for host D ....

Host B addresses:

• for host A ....
• for host D ....

Host D addresses:

• for host A ....
• for host B ....

Router C addresses:

• for host A ....
• for host B ....
• for host D ....

Exercise: Common LAN Technologies

Objective: Describe the topology and functionality of LANs.
Complete the following table to contrast Ethernet, Token Ring, and FDDI LAN technologies.

Summary

• The physical layer provides access to the wires of an internetwork.
• The data link layer provides support for communication over several types of data links:
  • LAN (Ethernet / IEEE 802.3, Token Ring / IEEE 802.5, FDDI).
  • Dedicated WAN (SDLC, HDLC, PPP, LAPB).
  • Switched WAN (X.25, Frame Relay, ISDN).

Exercise: Physical and Data Link Layers

Problem 1

Objective: Identify and describe the data link sublayers and their functions.
In the diagram, fill in the layer and sublayer names of the OSI model on the space provided inside each restangle. Then on the lines provided, write a brief description of the function performed by sublayers A and B.

A) ....

B) ....

Problem 2

Refer to the diagram in problem 1. Assume you have a logical address used by the function in Layer 3. Name a method used to find a device address used by the function in Layer 2. Write your answer on the line below.

....

Problem 3

Objective: Differentiate between LAN and WAN protocols.
Objective: Describe the characteristics of WAN-based protocols.
Entries in the table below list the names of a LAN or WAN protocol or standard in column 1. Column 2 statements summarize a LAN or WAN topology, function, or characteristic. In the left column (labeled Write Letters) write two answer letters in each space:

• Write L if the protocol or standard is used on LANs, or write a W if it is used on WANs.
• Also wrote the letter identifying the correct statemtns in column 2 that describes the given protocol or standard.

For example, for item 2, write W followed by C in the blakc space if you think item 2's protocol or standard is used on a WAN and summarized in item C.

Note Column 2 intentionally contains extra statements.

Solutions

Chapter 4 - Network Layer and Path Determination

Exercise: Network Layer Basics

Problem 1

Objective: List the key internetworking functions of the OSI network layer and how they are performed in a router.
Identify three key network-layer functions and briefly describe how a router performs these functions.

....

Problem 2

Objective: Describe the two parts of network addressing, then identify the parts in specific protocol address examples.
Fill in the blanks to complete the following statement:

The two general parts of a Layer 3 address are a ... part and a ... part.

Problem 3

Identify the protocol suite and the two parts of the common Layer 3 addresses shown:

A) 131.108.3.1 (assume a subnet mask of 255.255.0.0)
B) 1000.128 (assume a cable range of 1000-1000)
C) abadcafe.0000.0c56.de33
D) 31060004085551

Problem 4

Fill in the blanks:

A) A router keeps location information in a ....
B) The protocol that routers use to communicate locations to one another is a ....
C) How many tables are used in multiprotocol routing? ....

Summary

• Internetworking functions of the network layer include network addressing and best path selection for traffic.
• Network addressing uses one part to identify the path used by the router and one part for parts or devices on the net.
• Routed protocols direct user traffice, while routing protocols work between reouters to maintain path tables.
• Network discovery for distance vector involves exchange of routing tables; problems can include slower convergence.
• For link-state, routers calculate the shortest parhs to other routers; problems can include inconsistent updates.
• Balanced hybrid routing uses attributes of both link-state and distance vector, applying paths to several protocols.

Exercise: Network Layer and Path Determination

Problem 1

Objective: Contrast the network discovery and update processes in distance vector routing with those in link-state routing.
Fill in the blank lines in the graphic below with the letter of the statement of the statement that best describes that aspect of the routing protocol type. For example, enter the letter C in the Discovery box for Distance Vector Routing if you think that distance vector routing develops a view from neighbor routers' perspective.

Note You will not find a place for every statement.

A) Starts from a common view of internetworking topology.
B) Uses periodic updates, resulting in relatively slow convergence.
C) Develops a view from neighbor routers' prespectives.
D) Provides end-to-end load sharing.
E) Passes an updated routing table from neighbor to neighbor.
F) Events trigger updates for relatively fast convergence.
G) Processes updates in parallel with other routers.
H) Uses distance vector metrics and change-based updates.

Problem 2

Objective: List problems that each routing type encounters when dealing with topology changes, and describe techniques to reduce the number of these problems.
List one routing problem and indicate what type of routing is most likely to have the problem. Then list at least two techniques to solve (or reduce) that problem.

....

Problem 3

Objective: Explain the services of separate and integrated multiprotocol routing.
Describe at least one key difference between a separate multiprotocol routing environment and an integrated multiprotocol environment.

....

Problem 4

In the graphic, the ractangle identified as circle A shows a simplified Ethernet II frame. Other rectangles inside this frame represent encapsulations from various layers of TCP/IP. Identify these encapsulated components. Write the name for each component on the line pointing to the circled letter of the component. For example, the correct answer for the Ethernet II frame is provided on the line for component A.

Problem 5

Refer to the diagram shown in the problem 4. The following information represents part of the contents possible for TCP/IP layers. Each item on the list refers to a layer transition as information is decapsulated:

1. The packet carries IP.
2. Use Trivial File Transfer Protocol (TFTP).
3. The program begins using the port number 20.
4. Use the IP protocol number 17 (User Datagram Protocol).
5. The destination interface is 00000c123456; the source is 00000c135791.

On the following space provided, match the number of the contents description with its component letter. For example, write the answer 2 next to the letter D if Use Trivial File Transfer Protocol (TFTP) is your answer for layer transition information that component D could contain.

Note The numbered list of content descriptions intentionally contains an extra statement.

A) ____________
B) ____________
C) ____________
D) ____________

Problem 6

A) EIGRP and ISIS are examples of a new approach called _______.

B) Must the router be configured with network-layer addresses for most protocols? [ ] Yes [ ] No

C) Does the network-layer logical address change over each link? [ ] Yes [ ] No

D) What does ARP stand for and what does it do? _______

E) Is a frame routable? [ ] Yes [ ] No

Solutions