CCNA 1 and 2 Companion Guide, Revised (Cisco Networking Academy Program) part 41 ppt

Upon completion of this chapter, you will be able to ■ Identify the TCP/IP model components ■ Describe the future IP version ■ Discuss the relationship of TCP/IP to the OSI model ■ Ident

cut-through switching A packet-switching approach that streams data through a

switch so that the leading edge of a packet exits the switch at the output port before

the packet finishes entering the input port A device using cut-through packet

switch-ing reads, processes, and forwards packets as soon as the destination address is looked

up and the outgoing port is determined See also store-and-forward switching.

encoding Process by which bits are represented by voltages

fragment-free switching Switching that filters out collision fragments, which are the

majority of packet errors, before forwarding begins

latency Delay between the time when a device receives a frame and the time when

that frame is forwarded out the destination port

Manchester encoding Digital encoding scheme, used by IEEE 802.3 and Ethernet, in

which a mid–bit-time transition is used for clocking; a 1 is denoted by a high level

dur-ing the first half of the bit time

microsegmentation The division of a network into smaller segments, usually with

the intention of increasing aggregate bandwidth to network devices

NRZ (nonreturn to zero) Signals that maintain constant voltage levels with no signal

transitions (no return to a 0V level) during a bit interval

NRZI (nonreturn to zero inverted) Signal that maintains constant voltage levels with

no signal transitions (no return to a 0V level) It interprets the presence of data at the

beginning of a bit interval as a signal transition and interprets the absence of data as

no transition

SNR (signal-to-noise ratio) The ratio of useable signal being transmitted to the

undesired signal (noise) It is a measure of transmission quality The ratio of good data

(signal) to bad (noise) on a line, expressed in decibels (dB)

store-and-forward switching A packet-switching technique in which frames are

pro-cessed completely before being forwarded out the appropriate port This processing

includes calculating the CRC and checking the destination address In addition, frames

must be stored temporarily until network resources (such as an unused link) are

avail-able to forward the message

STP (Spanning Tree Protocol) Bridge protocol that uses the spanning tree algorithm,

enabling a learning bridge dynamically to work around loops in a network topology

by creating a spanning tree Bridge exchange BPDU messages with other bridges to

detect loops and then remove the loops by shutting down selected bridge interfaces

Thinnet Term used to define a thinner, less expensive version of the cable specified in the IEEE 802.3 10BASE2 standard

WDM (wavelength-division multiplexing) Multiple optical wavelength can share the same transmission fiber The spectrum occupied by each channel must be separated adequately from the other

Check Your Understanding

Complete all the review questions to test your understanding of the topics and con-cepts in this chapter Answers are listed in Appendix C, “Check Your Understanding Answer Key.”

1. What is the name of the method used in Ethernet that explains how Ethernet works?

A. TCP/IP

2. What is the maximum distance for thick Ethernet without using a repeater?

A. 185m (606.95 ft.)

B. 250m (820.2 ft.)

C. 500m (1640.4 ft.)

D. 800m (2624.64 ft.)

3. 10-Mbps Ethernet operates within the timing limits offered by a series of no more than segments separated by no more than

repeaters

A. Three, two

B. Four, three

C. Five, four

D. Six, five

4. Fast Ethernet supports up to what transfer rate?

A. 5 Mbps

B. 10 Mbps

C. 100 Mbps

D. 1000 Mbps

5. Identify two Gigabit Ethernet cable specifications.

A. 1000BASE-TX

B. 1000BASE-FX

C. 1000BASE-SX

D. 1000BASE-LX

E. 1000BASE-X

6. What is the transmission medium for 1000BASE-SX?

A. Long-wave laser over single-mode and multimode fiber

B. Category 5 UTP copper wiring

C. Balanced, shielded, 150-ohm, two-pair STP copper cable

D. Short-wave laser over multimode fiber

7. 4D-PAM5 encoding method is used in which of the following Gigabit Ethernet?

A. 1000BASE-LX

B. 1000BASE-SX

C. 1000BASE-T

D. 1000BASE-CX

8. What is the IEEE standard for 10-Gb Ethernet?

A. 802.3z

B. 802.3u

C. 802.3ae

D. 803.3

9. Which of the following is not a feature of microsegmentation?

A. It enables dedicated access

B. It supports multiple conversations at any given time

C. It increases the capacity for each workstation connected to the network

D. It increases collisions

10. Which of the following is used by LAN switches for making the forwarding decision?

A. IP address

B. MAC address

C. Network address

D. Host address

11. Which of the following is a feature of full-duplex transmission?

A. It offers two 10- to 1-Gbps data-transmission paths

B. It doubles bandwidth between nodes

C. It provides collision-free transmission

D. All of the above

12. The three common types of switching methods are ,

13. The Spanning-Tree Protocol allows which of the following?

A. Bridges to communicate Layer 3 information

B. A redundant network path without suffering the effects of loops in the network

C. Static network paths for loop prevention

D. None of the above

14. Which of the following is not one of the STP port states?

A. Blocking

B. Learning

C. Listening

D. Transmitting

15. Which of the following is true concerning a bridge and its forwarding decisions?

A. Bridges operate at OSI Layer 2 and use IP addresses to make decisions

B. Bridges operate at OSI Layer 3 and use IP addresses to make decisions

C. Bridges operate at OSI Layer 2 and use MAC addresses to make decisions

D. Bridges operate at OSI Layer 3 and use MAC addresses to make decisions

16. Which of the following is not a feature of bridges?

A. They operate at Layer 2 of the OSI model

B. They are more intelligent than hubs

C. They do not make any forwarding decisions

D. They build and maintain address tables

17. Which of the following statements is true of microsegmentation?

A. Each workstation gets its own dedicated segment through the network

B. All the workstations are grouped as one segment

C. Microsegmentation increases the number of collisions on a network

D. None of the above

18. Which of the following is true for LAN switches?

A. They repair network fragments known as microsegments

B. They are very high-speed multiport bridges

C. Lower bandwidth makes up for higher latency

D. They require new network interface cards on attached hosts

Upon completion of this chapter, you will be able to

■ Identify the TCP/IP model components

■ Describe the future IP version

■ Discuss the relationship of TCP/IP to the OSI model

■ Identify applications and protocols from each layer of the TCP/IP model

■ Identify the order and relationship of the four TCP/IP layers

■ Explain the format and significance of each of these components of an IP net-work: IP address, IP address classes, reserved IP address space, private IP address space, and IP subnetting

■ Calculate valid IP subnetwork addresses and mask values such that user/network requirements are met when given an IP address scheme

■ Explain the evolution of IP addressing, including the need for an increase in the size of the IP address space

Chapter 7

TCP/IP Protocol Suite and

IP Addressing

This chapter presents an overview of the Transmission Control Protocol/Internet Protocol (TCP/IP)protocol suite It starts with the history and future of TCP/IP Then it compares the TCP/IP protocol model to the OSI model, identifying and describing each layer of the TCP/IP protocol suite and how it relates to the Internet architecture TCP/IP is covered in more detail in Chapter 9, “TCP/IP Transport and Application Layer.”

This chapter also discusses IP addressing in depth This includes how to convert decimal and binary addresses and how to identify the different classes of IP addresses—Class A,

B, C, D, and E IPv4, which has been the standard by which IP addresses have been assigned for years, is being replaced by a much more advanced IP addressing scheme called IPv6

This chapter describes and compares IPv4 and IPv6

Be sure to look at this chapter’s associated e-Lab Activities, Videos, and PhotoZooms, which you will find on the CD-ROM accompanying this book These CD elements are designed to supplement the material and reinforce the concepts introduced in this chapter

Introduction to TCP/IP

The U.S Department of Defense (DoD) created the TCP/IP reference model, shown in Figure 7-1, because it wanted a network that could survive any conditions To illustrate further, imagine a world criss-crossed by different kinds of connections—wires, micro-waves, optical fibers, and satellite links Then imagine a need for data to be transmitted, regardless of the condition of any particular node or network on the internetwork The DoD wants its packets to get through every time, under any conditions, from any one point to any other point It was this very difficult design problem that brought about the creation of the TCP/IP model, which has since become the standard on which the Internet has grown

Figure 7-1 TCP/IP Protocol Suite Layers

In reading about the TCP/IP model layers, keep in mind the original intent of the Internet; it will help explain why certain things are as they are The TCP/IP model has four layers: the application layer, the transport layer, the Internet layer, and the network access layer It is important to note that some of the layers in the TCP/IP model have the same names as layers in the OSI model Do not confuse the layer functions of the two models The layer numbers are different, so the functions Layer 2 performs in the OSI model might not be the same as Layer 2 in the TCP/IP model For example, in the OSI model, Layer 3 is IP, just as Layer 2 in the TCP/IP model is IP Another case is the TCP/UDP functions at Layer 4 (the transport layer) in the OSI model and Layer 3 (the transport layer) in the TCP/IP model

The present version of TCP/IP is old Internet Protocol Version 4 (IPv4) was standard-ized in September 1981 In 1992 the standardization of a new generation of Internet Protocol (IP), often called IPng, was supported by the Internet Engineering Task Force (IETF) IPng is now called Internet Protocol Version 6 (IPv6) IPv6, shown in Figure 7-2, has not yet gained wide implementation, but it has already been released by most ven-dors of networking equipment and will become the dominant standard in the future

Figure 7-2 IPv4 Versus IPv6

Application Transport Internet Network Access

IPv4 Address

0 0 1 0 0 0 0 1 1 0 0 0 0 1 1 0 1 1 0 0 0 0 0 1 0 0 0 0 0 0 1 1

IPv6 Address

0 0 1 0 1 1 1 1 1 1 1 1 1 1 1 0 : 0 0 0 1 1 0 0 1 0 0 0 0 0 0 0 0

0 1 1 0 0 1 0 1 0 1 0 0 0 1 0 1 : 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1

0 0 0 0 0 0 1 1 0 0 1 1 0 0 0 0 : 1 1 1 1 1 0 0 0 0 0 0 0 0 0 1 0

0 1 1 1 1 1 1 0 1 0 1 1 1 1 1 1 : 0 0 0 1 0 0 1 0 1 1 0 0 0 0 1 0

3ffe:1900:6545:3:230:f804:7ebf:12c2

Application Layer

TCP/IP was designed with a high-level protocol layer that includes OSI session,

presen-tation, and application layer details The application layer, shown in Figure 7-3, handles

high-level protocols and issues of representation, encoding, and dialog control

Figure 7-3 TCP/IP Application Layer Protocols

The TCP/IP protocol suite combines all application-related issues into one layer and

ensures that this data is properly packaged for the next layer TCP/IP includes not only

Internet and transport layer specifications (such as IP and TCP) but also specifications

for common applications TCP/IP has protocols to support file transfer, e-mail, and

remote login, including the following applications:

■ Hypertext Transfer Protocol (HTTP)—The underlying protocol used by the

World Wide Web HTTP defines how messages are formatted and transmitted and what actions web servers and browsers should take in response to various commands

■ Trivial File Transfer Protocol (TFTP)—A connectionless service that uses User

Datagram Protocol (UDP) TFTP is used on the router to transfer configuration files and Cisco IOS images and to transfer files between systems that support TFTP It is useful in some LANs because it operates faster than FTP in a stable environment

Application

File Transfer

¥ TFTP*

¥ FTP*

¥ NFS E-Mail

¥ SMTP Remote Login

¥ Telnet*

¥ rlogin Network Management

¥ SNMP*

Name Management

¥ DNS*

*Used by the Router

Transport Internet Network Access

■ File Transfer Protocol (FTP)—A reliable, connection-oriented service that uses

TCP to transfer files between systems that support FTP It supports bidirectional binary file and ASCII file transfers

■ Network File System (NFS)—A distributed file system protocol suite developed

by Sun Microsystems that allows remote file access across a network

■ Simple Mail Transfer Protocol (SMTP)—Governs the transmission of e-mail over

computer networks It does not provide support for transmission of data other than plain text

■ Terminal emulation (Telnet)—Provides the capability to remotely access another

computer It lets a user log into an Internet host and execute commands A Telnet client is called a local host; a Telnet server is called a remote host

■ Simple Network Management Protocol (SNMP)—A protocol that provides a

means to monitor and control network devices and to manage configurations, statistics collection, performance, and security

■ Domain Name System (DNS)—A system used on the Internet to translate names

of domains and their publicly advertised network nodes into IP addresses

Transport Layer

Thetransport layerprovides transport services from the source host to the destination host It constitutes a logical connection between the network’s endpoints: the sending host and the receiving host Transport protocols, shown in Figure 7-4, segment and reassemble data that upper-layer applications send, into the same data stream between endpoints The transport layer data stream provides end-to-end transport services, sometimes called end-to-end services

Figure 7-4 TCP/IP Transport Layer Protocols

Application

¥ Transmission Control Protocol (TCP)

- Connection-Oriented

¥ User Datagram Protocol (UDP)

- Connectionless

Transport Internet Network Access