Cisco Press Internetworking Technologies Handbook 4th Edition pdf pdf

(1)

• Table of Content s

• I ndex

I nt e rn et w or k ing Te chnologie s H a ndbook , Four th Edit ion

By Cisco Systems, Inc.

Pub lish er: Cisco Press

Pub Dat e: Sep tem ber 1 1, 2 003 I SBN: 1- 58 705 -1 19 -2 Pages: 11 28

The u pdat ed edit ion of t he b est - selling all- in- one net w ork ing r ef erence p rov ides cover age of essent ial an d cu t t ing- edg e t ech nologies.

Con cise ov er v iew s of t echn olog ies essen t ial t o n et wor k ing pr ofession als at all lev els, f rom nov ice t o ex pert .

New chapt er s include cov erag e of im por t ant t opics like VoI P and EAP

Cov erag e of cut t ing edge t echn ologies lik e opt ical n et wor k ing and st or age

Aut h ored by Cisco Sy st ems, w or ldw ide leader in net w or king f or t he I n t er n et .

I n t ern et w or k in g Tech nologies Hand book, Four t h Ed it ion , is a com pr ehensive refer ence t hat enables net w or kin g p r ofessionals t o un derst and an d im plem en t cont em por ar y int er net w ork ing t echnologies. Mast er t he t er m s, con cep t s, t echn ologies, an d devices used in t oday ' s net w ork ing indu st ry . Lear n how t o incor por at e int er net w or kin g t echn olog ies in t o a LAN/ WAN env ir onm ent . Com plet e w it h new an d u pdat ed chapt er s on secur it y , st or age, opt ical net w or k in g, scalabilit y, and speed, t h is book is a com plet e an d u p- t o- d at e r ef er ence t o t he t op ics t hat are essen t ial t o all net w or kin g p rof essionals, r egar dless of ex pert ise.

(2)

(3)

(4)

(5)

(6)

(7)

(8)

(9)

(10)

(11)

(12)

(13)

(14)

(15)

• I ndex

Reader s w ill obt ain a g reat er un der st an ding of LAN and WAN n et w or k ing, p ar t icu lar ly t h e har dw ar e, pr ot ocols, and ser v ices inv olv ed . Fu ndam ent al t ech nology inf or mat ion is pr ov ided on a b r oad r ang e of int egr al sy st em s and serv ices, in clud ing det ailed descr ipt ion s, rev iew quest ions t o en su re con cept comp r eh en sion and r et en t ion, and ad dit ional r esou r ces f or fu rt her st udy . Cov erag e is also ext end ed n ot only t o new n et wor k ing concep t s, but also t o old er , legacy syst em s, pr ovid in g a m or e r ealist ic pict ur e of t he real- w or ld n et w or k ing en vir onm ent s in w hich pr of essionals oper at e. Tools and gu id elines f or opt im izing syst em per for m ance w ill incr ease pr odu ct iv it y an d im pr ov e eff iciency, help ing t he r eader m ake mor e in t elligent , cost - eff icient decisions for t h eir net w ork s.

Xer ox Net work Sy st ems

Bany an VI NES

(16)

(17)

(18)

(19)

• I ndex

t r adem ark s of Cisco Sy st em s, I nc. an d/ or it s af filiat es in t he U. S. and cer t ain ot her coun t ries.

All ot h er t rad em ar k s m en t ioned in t his d ocum en t or W eb sit e ar e t he p r opert y of t heir respect ive ow ner s. The use of t h e w or d p art ner does not im ply a p art nership r elat ion sh ip b et w een Cisco and any ot her comp any . ( 03 03R)

(20)

• I ndex

Icons Used in This Book

(21)

• I ndex

Command Syntax Conventions

The con vent ions used t o pr esent comm an d sy nt ax in t his b ook ar e t he sam e conv ent ions u sed in t he I OS Com m and Refer ence. The Com m and Ref er ence descr ibes t h ese conv en t ions as f ollow s:

Vert ical b ars ( | ) separ at e alt er nat ive, m u t ually exclusive element s.

Squ are br ack et s ( [ ] ) ind icat e an op t ional element .

Br aces ( { } ) ind icat e a r eq uir ed choice.

Br aces w it hin br ack et s ( [ { } ] ) in dicat e a r equir ed ch oice w it hin an opt ional elem en t .

Bold in dicat es com m ands and key w ord s t hat ar e ent er ed lit er ally as show n . I n conf ig ur at ion ex am ples and out p ut ( not general com m and syn t ax ) , bold indicat es com man ds t h at ar e m anu ally in put by t h e user ( such as a show com m and ) .

(22)

• I ndex

Introduction

Net w ork ing and t h e I n t ern et hav e becom e one of t h e m ost inf lu en t ial f orces in our lives t od ay. They cont inu e t o ch ange t he w ay w e w or k, liv e, play , and lear n. I n less t h an t en y ear s, t h e ent ir e w or ld has becom e conn ect ed, mak ing it easy and inex pensiv e t o comm u nicat e arou nd t he globe in st ant ly . Few wou ld ar g ue t hat t he I n t ern et has chan ged ev ery asp ect of our lives. I t ' s im pr oved educat ion and m ade t h e w orld' s inf or mat ion av ailable t o an y st udent any w her e, any t im e; it 's how w e com m unicat e w it h our r elat ives; it ' s how w e plan our v acat ions. We now hav e t h e w orld and it s inf or m at ion at our f inger t ips—creat ing n ew oppor t un it ies f or ever y bu sin ess, gov ern ment , educat ional in st it u t ion, an d in divid ual.

This b ook seek s t o g ive y ou a f und am en t al un derst an ding of t he d iff er ent con cept s and

(23)

• I ndex

Objectives

This b ook pr ov id es basic t ech nical infor m at ion about t he var ious t echn olog ies u sed in t he f ield of net w or kin g. I t is design ed f or use w it h ot her Cisco Pr ess book s and as a st an dalone r efer en ce t ool.

(24)

• I ndex

Updates to the Fourth Edition

(25)

• I ndex

Audience

(26)

• I ndex

Organization

This b ook is or ganized in t o t he follow ing nine sect ions:

P ar t I: I nt r oduct ion t o I nt e rne t w ork i ng— Prov ides int r odu ct ory in for m at ion ab out t he basic concept s and t echnolog ies of n et w or k ing, in clu ding LAN and WAN t echnologies, Cisco I OS sof t w are, b rid ging and sw it ch in g t echn ologies, r out in g pr ot ocols, an d n et wor k

m anagem ent .

P ar t I I: LAN Prot ocols— Cov er s LAN pr ot ocols and t heir t echnolog ies.

P ar t I I I: W AN Technol ogi es— Discusses WAN t echnolog ies, includin g Fr am e Relay, HSSI , I SDN, PPP, SMD S, dialup , SDLC, X. 25, and VPNs.

P ar t I V: Mu lt i se rv i ce A cce ss Te chnol ogie s— Prov ides ov er v iew infor m at ion on access net w or kin g t echn olog ies, includ in g voice/ dat a in t eg r at ion , w ir eless, D SL, cable, opt ical, VoI P, DPT/ SRT, and EAP.

P ar t V: Bri dgi ng an d S w it chi ng— Discusses br idging an d sw it ching t ech nologies, includin g t r an sp arent br idgin g, m ix ed - media br idging , sour ce- r out e br idging , LAN sw it ch in g and VLANs, ATM, MPLS, and d at a link sw it ching.

P ar t V I: N e t w ork P rot ocol s— Cov er s n et w or k in g pr ot ocols, in clud ing OSI P, I P, I Pv6 , Net War e, AppleTalk, I BM SNA, and DECnet .

P ar t V I I: Rout i ng P rot ocols— Prov ides ov er v iew infor m at ion on rou t ing pr ot ocols, includin g BGP, Enh anced I GRP, I BM SNA, I GRP, I nt er net Pr ot ocol Mu lt icast , Net War e Lin k-Serv ices, OSPF, OSI RP, r out ing inf or mat ion , r esour ce r eser vat ion , and SMRP.

P ar t V I I I: N e t w ork M a nag em e nt— Discusses secur it y t echnologies, dir ect or y - enabled net w or kin g, n et w or k caching t ech nologies, and st orag e net w or king .

(27)

(28)

(29)

• I ndex

m or e t han six year s of exp er ience in t he net w or kin g f ield . Since join in g Cisco in 20 00, he h as cont inu ed t o focus on secu rit y t echn ologies and pr oduct s. He cur r ent ly pr ov ides secur it y post u re assessment s and secur it y consult ing t o Cisco cu st omer s. He has t rain ed ot her Cisco eng ineer s in t he area of secur it y and w as t he t echn ical sp eak er at Cisco' s Net wor k ers Conv en t ion.

Al an Trou p is a t echnical w r it er for t h e Cisco MDS 900 0 fam ily of st or ag e sw it ches. He w as pr eviou sly a t ech nical pub licat ions man ager in one of Cisco's op t ical sw it ch div isions. He h as a bachelor of ar t s degr ee in Eng lish fr om San Jose St at e Univ ersit y .

(30)

• I ndex

Third Edition Contributors

(31)

• I ndex

First Edition Contributors

(32)

• I ndex

Part I: Introduction to Internetworking

Ch apt er 1 I n t er net w or k in g Basics

Ch apt er 2 I n t rod uct ion t o LAN Pr ot ocols

Ch apt er 3 I n t rod uct ion t o WAN Techn ologies

Ch apt er 4 I n t rod uct ion t o Cisco I OS Soft w ar e

Ch apt er 5 Br idg ing and Sw it ch in g Basics

Ch apt er 6 Rout ing Basics

(33)

• I ndex

Chapter 1. Internetworking Basics

Obj e ct i ve s

Lear n wh at m ak es up an int ern et wor k .

Lear n t he b asics of t he OSI m odel.

Lear n t he d if fer en ces b et w een con nect ion - orient ed and connect ionless ser vices.

Lear n about t he d iff er ent t yp es of addr esses used in an int er net w ork .

Lear n about flow con t rol and err or - check ing basics.

This chap t er w ork s w it h t he next six ch apt ers t o act as a f ound at ion f or t h e t ech nology discussion s t hat follow . I n t his chapt er , som e fu ndam ent al con cept s and t erm s u sed in t he evolv ing langu age of int er net w or king ar e add r essed . I n t he sam e w ay t hat t his b ook pr ov id es a fou ndat ion f or un derst and ing m odern net w or k in g, t h is chapt er sum m ar izes som e com mon t hem es pr esent ed t hr oug hout t he rem ainder of t h is book . Topics include flow cont r ol, er ror check ing , and m ult iplexin g, b ut t his chapt er f ocuses m ainly on m app in g t he Op en Sy st em

(34)

• I ndex

What Is an Internetwork?

An int ern et wor k is a collect ion of in div id ual n et w or k s, con nect ed by in t erm ediat e n et w or k ing dev ices, t hat fu nct ions as a single lar ge n et w or k . I nt er net w ork ing r ef ers t o t h e indu st r y ,

pr odu ct s, and pr ocedu r es t hat m eet t h e challen ge of creat ing an d ad min ist er ing int ern et wor k s.

Figur e 1- 1 illust r at es some diff er ent kin ds of net w or k t echnologies t hat can be int er connect ed by r out er s and ot her n et w or k ing devices t o cr eat e an int ern et wor k .

Figu r e 1 - 1 . Di ff e r en t N et w or k Tech nol ogie s Ca n Be Con ne ct ed t o Cr e at e

a n I n t e r ne t w or k

History of Internetworking

The f ir st net w or ks wer e t im e- sh aring n et w or k s t hat used m ainf r ames an d at t ach ed t er m in als. Such en vir onm ent s wer e im plem ent ed by b ot h I BM's Sy st em s Net w or k Ar ch it ect ur e ( SNA) and Digit al' s net w or k ar ch it ect ur e.

Local- area net w ork s ( LANs) ev olved ar ound t he PC r ev olu t ion. LANs en abled m ult ip le user s in a r elat iv ely sm all g eog rap hical ar ea t o ex ch ange files and m essages, as w ell as access shar ed r esour ces such as file ser v er s an d pr in t ers.

Wide- area net w ork s ( WANs) in t er conn ect LANs w it h geogr aphically dispersed user s t o creat e connect ivit y . Som e of t h e t ech nologies used f or connect ing LANs in clud e T1, T3 , ATM, I SDN, ADSL, Fr am e Relay , r adio link s, and ot h er s. New m et hods of conn ect ing d isper sed LANs are app ear ing ever y day .

(35)

• I ndex

I nt er net w ork ing evolv ed as a solut ion t o t h r ee k ey pr oblem s: isolat ed LANs, du plicat ion of r esour ces, and a lack of net w or k m anagem en t . I solat ed LANs mad e elect r onic comm u nicat ion bet w een dif fer en t of fices or depar t m ent s im possible. Dup licat ion of resour ces m eant t hat t he sam e har dw ar e and soft w ar e had t o be sup plied t o each off ice or depar t m ent , as d id separ at e supp ort st aff . This lack of net w or k m anag em ent meant t hat no cen t ralized met h od of m anag ing and t r oub leshoot ing n et w or k s exist ed.

Internetworking Challenges

I m plem ent ing a fu nct ional int er net w or k is no sim ple t ask . Man y challen ges m ust b e faced, esp ecially in t he ar eas of con nect iv it y , r eliabilit y , net w or k m anagem ent , an d f lex ibilit y . Each ar ea is k ey in est ablish ing an ef ficient and eff ect iv e int er net w or k.

The ch alleng e w hen conn ect ing v ar iou s syst em s is t o su ppor t com m un icat ion am ong dispar at e t echnologies. Diff erent sit es, f or exam ple, m ay u se d iff er ent t yp es of media operat in g at v ar ying speed s, or m ay even inclu de d if fer ent t yp es of sy st em s t h at n eed t o com m unicat e.

Becau se com pan ies r ely heav ily on d at a com mu nicat ion, int er net w or ks mu st pr ov ide a cer t ain level of r eliab ilit y . Th is is an u npr edict able w or ld, so m an y larg e int ern et wor k s include

r ed und ancy t o allow for com m unicat ion ev en w h en pr oblem s occu r .

Fur t her mor e, net w or k m anag em ent mu st pr ov ide cent r alized supp ort and t r oub leshoot ing capabilit ies in an int er net w or k. Conf igur at ion, secur it y, perf or man ce, an d ot her issues m ust be adequ at ely ad dr essed f or t h e int ern et wor k t o fu nct ion sm oot h ly . Secur it y w it hin an in t er n et w or k is essent ial. Man y people t h ink of net w or k secur it y f rom t he p er spect iv e of p rot ect ing t he pr iv at e net w or k fr om ou t sid e at t ack s. How ev er , it is ju st as im por t ant t o pr ot ect t he n et wor k f r om int er nal at t ack s, esp ecially because m ost secur it y br eaches come fr om inside. Net w ork s m ust also be secur ed so t hat t he int er nal n et wor k cann ot b e used as a t ool t o at t ack ot h er ex t ern al sit es.

Ear ly in t he y ear 20 00, m an y m ajor w eb sit es w er e t he v ict im s of d ist r ibu t ed d en ial of ser v ice ( DD OS) at t ack s. These at t acks w er e possible because a g r eat num b er of p r iv at e n et w or k s cur r en t ly con nect ed w it h t he I nt er net wer e not pr oper ly secur ed. Th ese pr iv at e net w or ks w er e used as t ools for t he at t ack ers.

(36)

• I ndex

Open System Interconnection Reference Model

The Op en Sy st em I nt er connect ion ( OSI ) refer ence m odel d escr ibes how in for m at ion f r om a soft w ar e app licat ion in one com put er m ov es t hr ough a net w ork mediu m t o a soft w ar e

app licat ion in an ot her com put er . The OSI r ef erence m odel is a concep t ual m od el com posed of sev en lay er s, each sp ecify ing par t icular n et w or k f unct ions. Th e m odel w as dev elop ed by t he I nt er nat ional Or ganizat ion for St andar dizat ion ( I SO) in 1 984 , and it is n ow considered t he pr im ary archit ect ur al m odel f or int er comp ut er com mu nicat ions. The OSI m odel div ides t he t ask s inv olved w it h m ov ing inf orm at ion bet w een net w or ked comp ut er s int o sev en sm aller , m or e m anageable t ask g r oups. A t ask or gr oup of t ask s is t hen assign ed t o each of t he sev en OSI lay er s. Each layer is r eason ably self - cont ained so t hat t he t ask s assigned t o each lay er can b e im plem ent ed independ en t ly. This enables t he solut ion s off ered by on e layer t o be u pdat ed w it hout adv er sely aff ect in g t h e ot her lay ers. Th e follow ing list det ails t he seven layer s of t he Op en Sy st em I n t er connect ion ( OSI ) r efer en ce m od el:

Lay er 7— Applicat ion

Lay er 6— Presen t at ion

Lay er 5— Session

Lay er 4— Tran sp ort

Lay er 3— Net w or k

Lay er 2— Dat a link

Lay er 1— Phy sical

NO TE

A h andy way t o r emem ber t h e sev en lay ers is t he sent ence " All people seem t o need d at a p rocessing . " The beginnin g let t er of each w or d cor r esp onds t o a lay er .

All— Applicat ion lay er

People— Presen t at ion lay er

Seem — Session lay er

To— Tran sp ort lay er

Need — Net w or k lay er

Dat a— Dat a link lay er

Pr ocessin g— Phy sical lay er

(37)

• I ndex

Figu r e 1 - 2 . The O SI Ref e r en ce M ode l Con t ai ns Se ve n I n de pen de nt

La ye r s

Characteristics of the OSI Layers

The sev en lay er s of t h e OSI r efer en ce m od el can be divid ed int o t w o cat egor ies: upp er lay er s and low er layer s.

The up per lay er s of t he OSI m od el deal w it h applicat ion issues and gener ally are im plem en t ed only in soft w ar e. The h ighest lay er , t he app licat ion layer , is closest t o t he en d u ser . Bot h users and app licat ion layer p rocesses int er act w it h soft w ar e app licat ions t hat con t ain a

com mu nicat ion s com ponent . The t er m up per layer is som et im es used t o r efer t o any lay er abov e anot h er layer in t he OSI m odel.

The lower lay ers of t h e OSI m odel h andle d at a t r anspor t issues. The phy sical lay er and t he dat a link lay er are im plem en t ed in har dw ar e an d sof t w are. Th e lowest lay er, t he p hy sical lay er , is closest t o t he p hy sical n et wor k m edium ( t he n et w or k cabling , for ex am ple) and is r esp onsible for act ually placing infor m at ion on t he m edium .

Figur e 1- 3 illust r at es t he division bet w een t he u pper an d low er OSI lay ers.

(38)

• I ndex

Protocols

The OSI m odel pr ov ides a concept u al fr am ewor k f or com mu nicat ion b et w een com pu t er s, b ut t he m odel it self is n ot a m et h od of com m unicat ion. Act u al comm u nicat ion is m ade possible b y using com mu nicat ion p rot ocols. I n t he cont ex t of d at a n et w or k in g, a pr ot ocol is a for m al set of r ules and conv ent ions t h at g over ns h ow com put er s exchan ge inf or mat ion ov er a net w or k m edium . A pr ot ocol im plem en t s t he f un ct ion s of one or m or e of t h e OSI lay er s.

A w ide var iet y of comm un icat ion pr ot ocols exist . Som e of t h ese p rot ocols includ e LAN p r ot ocols, WAN p r ot ocols, n et w or k pr ot ocols, and r out ing p rot ocols. LANpr ot ocols op er at e at t h e phy sical and dat a link lay er s of t h e OSI m odel an d define com m unicat ion over t h e v arious LAN m edia.

WANpr ot ocols op er at e at t h e lowest t hr ee lay ers of t he OSI mod el and defin e com m un icat ion ov er t he v ar iou s w ide- ar ea m ed ia. Rou t in g pr ot ocols ar e n et wor k lay er pr ot ocols t hat ar e

r espon sib le for ex ch angin g in for m at ion b et w een rou t er s so t hat t he r out er s can select t he p rop er pat h f or net w or k t r aff ic. Finally , net w or k pr ot ocols ar e t he v ariou s upp er - lay er pr ot ocols t hat exist in a given pr ot ocol suit e. Man y pr ot ocols r ely on ot her s f or oper at ion. For exam p le, m any r out ing pr ot ocols use n et w or k p rot ocols t o ex chan ge inf orm at ion bet w een r out er s. This concept of bu ild in g upon t he lay er s already in ex ist ence is t h e fou ndat ion of t he OSI m odel.