Cisco press CCIE professional development routing TCPIP volume 1 2nd edition oct 2005 ISBN 1587052024

CCIE Professional Development Routing TCP/IP, Volume I, Second EditionBy Jeff Doyle - CCIE No.. Publisher: Cisco Press Pub Date: October 19, 2005 ISBN: 1-58705-202-4 Includes configurati

CCIE Professional Development Routing TCP/IP, Volume I, Second Edition

By Jeff Doyle - CCIE No 1919, Jennifer Carroll - CCIE

No 1402

Publisher: Cisco Press Pub Date: October 19, 2005 ISBN: 1-58705-202-4

Includes configuration and troubleshooting lessons that would cost thousands to learn in a classroom and numerous real-world examples and case studies

Praised in its first edition for its approachable style and wealth of information, this new edition provides readers a deep understanding of IP routing protocols, teaches how to implement these protocols using Cisco routers, and brings readers up to date protocol and

implementation enhancements Routing TCP/IP, Volume 1, Second Edition, includes

protocol changes and Cisco features that enhance routing integrity, secure routers from attacks initiated through routing protocols, and provide greater control over the

propagation of routing information for all the IP interior routing protocols Routing TCP/IP,

Volume 1, Second Edition, provides a detailed analysis of each of the IP interior gateway

protocols (IGPs) Its structure remains the same as the best-selling first edition, though information within each section is enhanced and modified to include the new developments

in routing protocols and Cisco implementations What's New In This Edition? The first edition covers routing protocols as they existed in 1998 The new book updates all covered routing protocols and discusses new features integrated in the latest version of Cisco IOS Software IPv6, its use with interior routing protocols, and its interoperability and

integration with IPv4 are also integrated into this book Approximately 200 pages of new information are added to the main text, with some old text removed Additional exercise and solutions are also included.

CCIE Professional Development Routing TCP/IP, Volume I, Second Edition

By Jeff Doyle - CCIE No 1919, Jennifer Carroll - CCIE

No 1402

Publisher: Cisco Press Pub Date: October 19, 2005 ISBN: 1-58705-202-4

CCIE Professional Development Routing TCP/IP Volume I Second Edition

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Jennifer

Jeff Doyle (CCIE No 1919) specializes in IP routing protocols,

MPLS, and IPv6 He has designed or assisted in the design oflarge-scale IP service provider networks throughout North

America, Europe, Japan, Korea, and the People's Republic ofChina Jeff has presented numerous corporate seminars, andhas also spoken at NANOG, JANOG, APRICOT, and at IPv6

internetworking courses on routing protocols and Cisco routersover the past 15 years Jennifer can be contacted at

jennifer.carroll@ieee.org

Frank Knox, Chief Technical Officer, has been with Skyline

Computer for a little over six years He is a dual CCIE (CCIE No.3698: SNA/IP and Routing/Switching) as well as a CCSI In

addition to his CTO responsibilities, Frank teaches several

advanced Cisco-related courses, including a one-week CCIE LabPreparation Workshop He is considered to be an expert in

mainframe attached router technologies and in the technologiesand issues associated with integrated networking (for example,SNA/IP and Voice/Data) He has more than 37 years of

networking experience with IBM, GTE (Verizon) Directories, andSkyline Computer Corp This experience includes field service,field support, product planning, management, and all facets ofnetworking education In addition, he developed and taughtseveral courses for the University of Dallas TelecommunicationsMBA program Frank also has an MS degree in

protocol scalability, working with customers to implement

scaling functionality in their network, and participating in eventssuch as Networkers to educate others on how to enhance theirnetwork's performance and scalability from the routing

perspective

Rena Yang is a software engineer at Cisco Systems She has

more than six years of experience implementing code in CiscoIOS She currently works on IS-IS Before this, she focused onIPv4, UDP, access lists, policy routing, and routing

infrastructure Rena holds a bachelor's of science and masters

Many thanks to Brett Bartow, Chris Cleveland, Andrew Cupp,San Dee Phillips, and all of the staff of Cisco Press who madethis book possible

The technical editors, Steven Moore, Rena Yang and FrankKnox, did a fantastic job We want to thank them for theiroutstanding advice and recommendations

We want to thank Frank Knox, Carl Pike, Chris Tonini, and therest of the employees of Skylabs networks Skylabs' lab setupand access to the lab is easy to use and had everything weneeded to complete all the configurations and case studies inthis book

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The conventions used to present command syntax in this bookare the same conventions used in the IOS Command Reference.The Command Reference describes these conventions as

follows:

Boldface indicates commands and keywords that are

entered literally as shown In actual configuration examplesand output (not general command syntax), boldface

Square brackets [ ] indicate optional elements

Braces { } indicate a required choice

Braces within brackets [{ }] indicate a required choice

within an optional element

In 1976, when I saw my first Arpanet IMP at Digital EquipmentCorporation, networks as we know them today were in theirinfancy SNA, XNS, and DECnet were under early development,and packet switching versus circuit switching was the hot topic

of the day Those of us involved in the design of the switchingand routing algorithms were dealing with routers (although wedidn't call them that) that had 64 kilobytes of memory, data link

of 56 kilobits were considered blindingly fast, and networks with

256 nodes were big enough that if you were the salesman whosold those 256 computers, you would retire fabulously wealthy

Thirty years is a long time, and today the individual networksthat make up the Internet contain thousands or tens of

thousands of nodes, while the Internet as a whole contains

hundreds of millions of computers Most striking in the evolutionover this human generation is that the foundations of the

Internet laid down in the TCP/IP protocol suite have survivedmostly intact through four or more generations of computingarchitectures, three complete generations of operating systemtechnology, and an increase of five orders of magnitude in

transmission speeds

Yet, we still treat routing in packet-switched networks as a

black art Why is that?

First, designing robust, scalable distributed algorithms is hard.Despite our best intentions to make them simple, complexitycreeps in to deal with the inevitable special cases,

optimizations, peculiar topologies, and link technologies oneencounters Because a "fork lift upgrade" of an entire network israrely feasible, we have multiple generations of technology

present simultaneously, and we must maintain backward-compatibility with essentially no disruption to deployed services

As policies governing the routing of packets become more

Finally, as the environment in which these networks are

operated has evolved from a cooperative one where trust wasimplicit to one in which the network is subject to both insideand outside attack, designing and deploying routing systemsthat can be made secure has become an urgent priority

Routing TCP/IP tackles this black art comprehensively The

present Volume 1 covers all the needed fundamentals of TCP/IPnetworks and gives you all the tools needed to understand howrouting is accomplished within a single administrative region ofthe Internet Straightforward ideas of packet-switched routingare presented first in the chapters on addressing and static

routing The most popular IGPsRIP, EGRP, OSPF, and ISISarecovered in depth Advanced topics in route redistribution, routefiltering, and policy routing round out Volume 1

David Oran

Cisco Fellow

Cisco Certified Internetwork Experts are widely recognized fortheir ability to design, troubleshoot, and manage large

networks This recognition comes from the fact that you cannotbecome a CCIE by attending a few classes and then

regurgitating some memorized facts onto a written test A CCIEhas proven expertise in an intense, famously difficult hands-onlab exam

This book is the first of two volumes that focuses on TCP/IP

routing issues Early in the writing of the first edition, Kim Lew,former Cisco Systems program manager, said, "Our objective is

to make CCIEs, not to make people who can pass the CCIE lab."

We entirely agree with that statement and have used it as aguiding principle throughout the writing of this book Althoughthe book includes many case studies and exercises to help youprepare for the CCIE lab, my primary objective is to increaseyour understanding of IP routingboth on a generic level and as

it is implemented on Cisco routers

The audience for this book is any network designer,

administrator, or engineer who needs a full understanding of theinterior routing protocols of TCP/IP Although the practical

aspects of the book focus on the Cisco IOS, the information isapplicable to any routing platform

The book is not only for readers who plan to become CCIEs, butfor people who wish to advance their knowledge of TCP/IP

routing These readers will fall into one of three categories:

The "beginners" who have some basic networking

knowledge and wish to begin a deep study of networking

The intermediate-level networking professionals who haveexperience with routers, Cisco or otherwise, and plan toadvance that experience to the expert level

The highly experienced networking experts These

individuals have extensive hands-on expertise with Ciscorouters and are ready to take the CCIE lab; however, theywant a structured review and series of exercises for

verification and validation

CCIE Professional Development: Routing TCP/IP, Volume I

focuses primarily on intermediate-level networking

professionals while offering to beginners a structured outline offundamental information and to experts the required challenges

to hone their skills

There are several factors influencing the changes contained inthis second edition The first factor is the CCIE itself When I(Jeff) wrote the first edition of this book, the CCIEspecificallywhat is now called the Routing and Switching specialty of theCCIEwas the only certification Cisco Systems offered Now,

there is a series of certifications creating a path to the CCIE atthe pinnacle Moreover, the typical networking professional ismore knowledgeable than in 1997 Given this, we have

eliminated the first chapter of the original book, which coveredsuch very basic concepts as the definition of bridges and routersand network addresses (When was the last time you even saw

a bridge in a network?)

The second factor influencing the changes in this edition is thechanges in the Cisco Systems IOS IGRP, which was frequentlyused when the first edition was written, is now a legacy protocolwhose main significance is as the ancestor of EIGRP Thereforethe IGRP chapter of the first edition has been eliminated andIGRP is covered for historical perspective early in the EIGRPchapter The IOS command suite itself has expanded to

accommodate new functions and options; we have made everyeffort to include the commands and protocol extensions that didnot exist in the late 1990s

Lastly, a protocol that existed mostly only in proposal form in1997IPv6is now in the early stages of worldwide deployment.You can expect to need a detailed knowledge of this protocoland the extensions to IP routing protocols that support it in thenear future, if not already, so this second edition delves deeplyinto routing IPv6

Other changes in this edition are semantic For example, in thefirst edition, I (Jeff) made a point of differentiating between a

"network" as a data link and an "internetwork" as a set of

everything from a local link to worldwide autonomous systemsoperated by the likes of Level 3, NTT, and Sprint We haveattempted to bring the terminology in this edition up to

modern, common usage

1

In addition to the RIP configurations shown here, a subnet of 192.168.5.0 must

be configured between RTE and RTF, using secondary addresses Otherwise, subnets 192.168.5.192/27 and 192.168.5.96/27 are discontiguous The RIP configurations are

Because the update timer is changed, the invalid, holddown, and flush timers must also be changed Setting the invalid and holddown timers to six times the update period, as the default timers are, would make the conversion time of the network extremely high Therefore, the invalid and holddown timers are set to three times the update period The flush timer must be longer than the holddown timer, so it is set to 60 seconds longer.

Network 192.168.4.0 is two hops from RTA, so adding 14 to the metric will give the route an unreachable metric of 16 Remember that in Configuration Exercise 1

a subnet of 192.168.5.0 had to be configured on the same link as 192.168.4.0 using secondary addresses, so that the subnets of 192.168.5.0 are contiguous Therefore, 192.168.5.0 is also two hops from RTB Assuming the interfaces of RTA and RTB connected to RTC are E0 on both routers, the configurations are

However, packets can still be routed if Proxy ARP is enabled For example,

suppose RTA has a packet to forward with a destination address of 192.168.20.50 RTA incorrectly interprets this address as a member of its subnet

192.168.20.32/27, and ARPs for the MAC identifier of 192.168.20.50 on that subnet RTB hears the ARP; it correctly interprets 192.168.20.50 as being a

member of its subnet 192.168.20.48/29 and responds with the MAC identifier of its interface on 192.168.20.32/29 RTA then forwards the packet to RTB, and RTB forwards the packet to the correct destination If Proxy ARP is disabled, packets will not be delivered correctly from RTA to RTB.

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