3Com 3 manual

http://www.3com.com/ Par t No. DU A173 0-0 BAA0 1 Publ ished Apr il 2002 Sup erStac k ® 3 Swit ch Im ple me nt ati on Guide Generic guide for units in the SuperStack 3 Swi tc h 4200 Series: 3C1 7300, 3 C17302[...]

3Com Cor poration 5400 Bayfr ont Plaza Santa Cl ara, Cali fornia 95052- 8145 Copyri ght © 200 2, 3Com T echno logies . All r ight s reserved . No part of this do cume ntation ma y be reprodu ced in any for m or by a ny mea ns or used to make any deriva tive work (such as translat ion, tra nsforma tion, or adapta tion) withou t writt en permi ssion[...]

C ONTEN TS A BOUT T HIS G UIDE Conventions 8 Related Doc umentation 9 Documentation Comme nts 9 Product Regi s trati on 1 0 1 S WITCH F EATURES O VERVIEW What is Management Softw ar e? 13 Swit ch Feature s Explai ned 13 Automatic IP C onfigurati o n 14 Port Securi ty 14 Aggregated L inks 14 Auto-negotiation 14 Mult ica st F ilte ring 15 Spanning T [...]

3 U SING M ULTICAST F IL TERING Wha t is an IP Multic ast ? 2 7 Benefits o f Multicast 28 M ult ica st F ilter ing 28 Mult ica st Filt erin g an d Y our Swit ch 2 9 IG MP Mu ltic ast Filt er ing 3 0 4 U SING R ESILIENC E F EATURES Spanning T ree Pr otocol (STP) 33 Rapi d Spanning T r ee Pr otoc ol (RSTP) 34 What is S TP? 34 How ST P W orks 36 STP R[...]

7 S TATUS M ONI TORIN G AND S TATIST ICS RMON 53 What is RMON? 53 The RMON Groups 54 Benefits o f RMON 54 RMON and the Switch 55 Alar m Events 5 6 The Defa u lt Al arm Settings 56 The Audi t Log 57 Email Notification of Events 57 Har d ware Status Monitoring 5 8 8 S ETTING U P V IR TUAL LAN S What a re V LANs? 61 Benefits o f VLANs 62 VLANs and Y o[...]

Configuration Rules w ith Full Duplex 77 B N ETWORK C ONF IGURATIO N E XAMPLE S Simple Network Configuration Exam ples 80 Segmen tation Swi tch Example 80 Collapsed Backbo ne Switch Examp le 81 Desk top Switch Example 82 Advanced Network Configuration Examples 83 Im prov ing the Resilience of Y our N etwork 83 Enhanc ing the Performance of Y our Ne[...]

A BOUT T HI S G UI DE This gui de describ es the features of the Super Stack ® 3 S w itch 4 200 Series and outl ines how to use the se featur es to optimize th e perf ormance of yo ur netwo rk. This gu ide is intend ed for the system or ne twor k admini strator who is r esponsible for c onfiguring, u sing, and managing the Switches. It assum es a [...]

8 A BOU T T HIS G UID E Conve ntions Ta b l e 1 an d Ta b l e 2 li st conve ntions t hat ar e used th r ough out this gui de. Ta b l e 1 Notice Icons Ic on Notice Type Descripti on In form atio n note Info rmatio n that descri bes i mporta nt featu res o r ins truc tio ns Cauti on Info rmatio n that alert s you t o potent ial loss of data or potent[...]

Relat ed Docume ntation 9 Related Do cumen tati on In addi tion t o thi s gu ide, ea ch Sw itch docum en tat ion set incl ude s the fo llow i ng : ■ Gett ing Start ed Guide This gui de contains: ■ all th e information y o u need to inst all and set up the Switch in its defa ult s tate ■ i nf or mat io n on ho w to acc es s t he ma nag em en t[...]

10 A BOU T T HIS G UID E Pl ease include th e followi ng informat ion when co ntacting us: ■ Document title ■ Do cu ment par t n umb er ( on t he t it l e pag e) ■ Page numb er (if appr opria te) Exampl e: ■ Su pe rSt ack 3 Sw it ch I mpl eme nt ati on Gu id e ■ Part num be r: DUA 17 30-0BA A0x ■ Page 25 Please note t hat we ca n onl y [...]

I S WITCH F EAT UR E S Chapter 1 Swi tch Featur es Overvi ew Chapter 2 O pti mi zi ng B and wi dth Chapter 3 Using M ulticast Filteri ng Chapter 4 Using Re silience Fe atures Chapter 5 Using the Swit ch Database Chapter 6 Usin g T r affi c Pr iorit izati on Chapter 7 Statu s Monito ring and Sta tist ics Chapter 8 Setti n g Up Virtual LA N s Chapter[...]

12[...]

1 S WITCH F EA TURES O VERV IEW This c hapt er conta ins int ro ductory inform ation ab out the Sup erStac k ® 3 Switch mana g ement software a nd suppor ted fe atures. It co ve rs th e followi ng t opics: ■ What is M anageme nt So ftw ar e? ■ Swi tch Featur es Exp lained For de tailed desc ript ions of the web interfac e operation s and the c[...]

14 C HAPTER 1: S W ITCH F EATURES O VER VIE W Automatic IP Conf igur ati on By def ault th e Swit ch tries to confi g ur e i tself wi th IP in format ion with out r eq uesting user interven tion. It uses the foll owing indust ry sta ndard methods to al locate the Swit ch IP information: ■ Dy nami c H ost Co nf ig ur at ion P r otoc o l ( DHC P) ?[...]

Swit ch Fea tures Expl ained 15 F or de tai l s of th e aut o- ne go ti ati on f ea tu re s s upp o rt ed b y y our Swit ch , please refe r to the Get ting Star ted Guid e that acc ompanies yo ur Switch. Ports o perat ing at 10 00 M bps on ly sup port full du plex m ode. Dupl ex Fu ll du plex m ode al lows pa ck ets to b e tra nsmitted and rece ive[...]

16 C HAPTER 1: S W ITCH F EATURES O VER VIE W Spannin g T r ee Pr otocol and Rapi d Span ning T ree Pr otocol Spann ing T ree Pro tocol (STP) and Rapid Span ning T r ee Protocol (R STP) ar e brid ge-based sys tem s that m akes your netwo rk more r esilient t o l ink f ail ur e a nd als o pr ovi de s pr ot ec ti on fr om ne two rk l oo ps — one of[...]

Swit ch Fea tures Expl ained 17 This sy stem is compatib le with the r elevant section s of the I EEE 802.1D/D17 stan dard (inc orporating IEEE 802.1p). For more inform atio n about 802.1 D and traffi c prio riti zati on, see Chapter 6 “ U si ng T ra ffic P rio ri ti zat io n” . Qu ality of Serv ice T raf fic p riorit izatio n can be t aken on [...]

18 C HAPTER 1: S W ITCH F EATURES O VER VIE W VLANs A V irtua l LA N (V LAN ) is a flexib le g r o up o f de vices t hat can b e l ocat ed any where in a net work, but which communic ate as i f they ar e on the same ph ysical segm ent. W i th VLAN s, yo u c an segm ent you r netw ork witho ut bei ng restrict ed b y physica l conn ection s — a lim[...]

2 O PTIM IZIN G B ANDWIDTH There are m any wa ys you c an op timize the b a ndwidt h on y our netw ork and im prove n etw ork pe rfo rma nce. If you u til ize cer tain S witc h fe atures you ca n provide the follow ing benef its to y our ne tw ork a nd en d users: ■ I n creased bandwidth ■ Qui cker connecti o ns ■ Faster tr ansfer o f data ?[...]

20 C HAPTER 2: O PTIMIZING B ANDWIDTH If t he dev ices a t eithe r end o f a link do no t suppo rt a uto-ne gotia tion, both en ds m ust be man ually se t to full duple x or hal f dup lex acc ordingly . Ports o perat ing at 10 00 M bps sup por t full du plex m ode o nly . Flow Contr ol All S wit ch ports supp ort flow co ntr o l, which is a mechan [...]

Po rt F eatur es 21 port and react acc ordingly . In other words, a uto- negotia tion ma y “ag ree” upon a con figurat ion that th e cable cann ot sustain ; smart au to-sens ing can det ect this an d adjust the l ink accor dingly . For exa mple, sma rt auto- sensing ca n detect network pr o blems , such as an un acce ptabl y hi gh error rate o [...]

22 C HAPTER 2: O PTIMIZING B ANDWIDTH Aggr egated Lin ks Aggr egated lin ks are c onnectio ns that all ow devic es to communicat e using up to tw o links in paral lel. Aggregate d links a r e su pporte d o n the 10/100 /100 0BASE -T por ts onl y . Th e se parallel lin ks pro vide two benefit s: ■ They c an p oten tially dou ble th e ba ndw idth o[...]

Ag g re gat ed Li nks 23 ■ I f p or ts of a di ffe ren t speed ar e aggr eg ated togeth er , t he higher speed links ca rry the tr aff ic. The lo wer speed lin ks onl y carry the traf fic if t he higher sp eed lin ks fail . ■ The aggr egated link d oes not support securit y . ■ Membe r lin ks must retain t he sam e group ings at both en ds of[...]

24 C HAPTER 2: O PTIMIZING B ANDWIDTH T raff ic D istr ibu tion an d Link Fail ur e on A ggr egat ed Lin ks T o maximi ze thro ughput , all traf fic is di stri buted acr oss the indiv idual li nks that m ak e up an agg regat ed link. Ther e fore, wh e n a packet is made avail able fo r trans m i ssion down an aggregat ed lin k, a hardwar e-based tr[...]

Ag g re gat ed Li nks 25 Agg r egate d Link Exam ple The example sh own in Figu re 3 il lustrat es an 2 Gbps aggr egated l ink be twe en t wo S wi tch u ni ts. Figure 3 A 2 Gbps aggrega ted link between two S witch units T o set u p this config urati on: 1 Add t he 1000B ASE-T ports on the upper u nit to the ag gr egated link. 2 Add t he 1000B ASE-[...]

26 C HAPTER 2: O PTIMIZING B ANDWIDTH[...]

3 U SING M ULTICA ST F ILTERING Mul ticast f iltering improve s the p erf ormanc e of net works t hat ca rry mu lt ica st tr a ffic . This cha pter explains m ult icasts, mult icast fi ltering, and h ow mult icast filter ing c an be i mpl ement ed on yo ur Sw itch . It cove rs t he f ollow ing to pi cs: ■ What is an IP Mult icast? ■ Multic ast [...]

28 C HAPTER 3: U SING M ULTIC AST F ILTERING A multic ast packet is identi fied by t he presen ce of a multi cast gr oup addr ess in th e destinat ion addr ess fi eld of the pac ket’ s IP header . Be nefits of M ulticast Th e benefit s of using IP multicas t ar e that it : ■ Enable s the simul taneous d eliv ery of informati on to many receive [...]

Mult ic ast Filt erin g 29 Figure 4 The ef fect of mult icast filter ing Mult icast Fi lterin g and Y our Switc h Y our Switch pr ovides auto m at ic multi cast fil tering sup port usi ng IGMP (Inter net Group M anage m ent P r otoc ol) Sno oping . It also supp orts I GMP query m od e. Snoo ping M ode Snoo ping M ode allo ws yo ur S witch to fo rwa[...]

30 C HAPTER 3: U SING M ULTIC AST F ILTERING comma n d will c onfigure t he Sw itch 42 00 Series to auto mat ically nego tiate wi th c omp atible devic es on V LAN 1 to beco me t he qu erier . The Swit ch 4200 Serie s is compatible with any device that confo rms to the IGMP v2 protoco l. IGMP Mult ica st Filt erin g IGMP is the system t hat a ll IP[...]

IG MP Mult ic ast Filt erin g 31 I f IGMP mult icast l earn ing i s not enabled t hen I P multi cast tr aff ic is alway s forwa rded, th at is, it floods t he net wor k. F or i nf or ma ti on a bou t co nf ig ur in g I GMP f un ct io na li t y on a n e nds t ati on, r efe r to the use r doc um en tat ion s up pli ed wi th yo ur en dst ati on or th [...]

32 C HAPTER 3: U SING M ULTIC AST F ILTERING[...]

4 U SING R ESILIENC E F EA TUR ES Settin g up resilie nce o n your net work helps prote ct cri tical link s agai nst failure, prote cts aga inst ne twork l oops, a nd reduc es ne twork d ownt ime to a mi nimum. This c hapter ex plains th e featur es suppor ted by the Swi tch that pr o vide resi lie n ce fo r y o ur ne two rk . I t c o ve rs th e fo[...]

34 C HAPTER 4: U SING R ESILIENCE F EATURES Rapi d Spa nnin g T re e Protoco l (RSTP) The Rapid Spannin g T ree (RSTP) is an enh anced Spanni ng T r ee featu re. RSTP imp lements the Spa nning T ree Algori thm and Pr otocol, as defined in the I EEE 802.1w standar d. 3Com rec omme nds that yo u us e the Rapid Spa n ning T ree P rot ocol feat ure (e [...]

What is STP? 35 Figure 5 A network configurat ion that cr eates l oops Figu r e 6 shows the r esult of enabl ing STP on t he bri dges in the conf igurati on. STP detec ts the d uplicat e paths and p revent s, or block s , one of them fr om forwar ding traf fic, so this c onfiguration will work sat isfact orily . STP has d e termined th at traf fic [...]

36 C HAPTER 4: U SING R ESILIENCE F EATURES Figure 7 T raf f i c flowing through Br idge B STP det ermines whi ch is the most effi c ie nt path bet ween each bridge d segm ent and a specifi c al ly assig ned re fere n ce poi nt on the netwo rk. Once the most ef ficient path has b een determ ined, all other p aths ar e blocked. Ther efor e, in Figur[...]

How STP Wor ks 37 cost , the l ess eff ic ient the li nk. T able 3 shows the default port c osts for a Swi tch. Ta b l e 3 De fault p ort co sts STP C al culation The fi rst stage in th e S TP proces s is the c alculatio n stage. Dur ing this st age, eac h bridge on the n etwork trans mits BPDUs th at all ow the s ystem to w ork out : ■ The i den[...]

38 C HAPTER 4: U SING R ESILIENCE F EATURES STP Co nfigura tion After al l the brid ges on the n etwork hav e agreed on the identit y of the Root B ridg e, and have est ablish ed the othe r relevant para met ers, eac h bridge is c onfigured to forward traffic o nly b etwee n its R oot Port and the Designa ted Br idge P orts for the respe ctive n et[...]

How STP Wor ks 39 Figure 8 Po rt cost s in a netw ork ■ Bri dge A has the lowest Bridge Ident ifi er in the n etwork, and has ther efore been selected as the Root Bri dge. ■ Becau se Bridge A is t he Ro ot Brid ge, it is also the D esignated Br idge for LAN segment 1. Port 1 on Brid ge A is ther efore sel ec ted a s the Designa ted Br idge P or[...]

40 C HAPTER 4: U SING R ESILIENCE F EATURES ■ Bri dge C has been selected as the De signated Bridge fo r LAN segmen t 3, be cause i t offers th e low est Root Pa th Cos t for LAN Segme nt 3 : ■ the route through Bridges C and B costs 20 0 (C to B=1 00, B to A =100) ■ the rout e through Bridge s Y and B co sts 300 (Y to B =200, B to A =1 00). [...]

How STP Wor ks 41 Figure 9 STP configur ations[...]

42 C HAPTER 4: U SING R ESILIENCE F EATURES Def ault Behavio r This sec tion con tains impor tant infor mation to note whe n using the RSTP and Fast Start fea tures, parti cularly if you alr eady have exist ing Switc h 4200 u nits in you r networ k wi th an ol der v ersion of soft ware. RSTP De fault Behavi or When using th e RSTP f eature, n ote t[...]

Usin g STP on a Netwo rk with Multi ple VLANs 43 Figur e 10 Configuration tha t separates VLANs T o avoid any VLAN subdivisi on, it is r ecommended that all inter -Switch co nnect ions are made mem bers of all avai lable 802.1Q VLAN s to en sure connec tivit y at all times. F or ex ample, th e connect ions between Switches A and B, an d bet wee n S[...]

44 C HAPTER 4: U SING R ESILIENCE F EATURES[...]

5 U SING THE S WITCH D AT A BAS E What is th e Swit ch Dat abase? The Swit ch Database is u sed by the Swit ch to determ ine wher e a packet should be forwa rded t o, an d which port sh ould tran smit the packe t if it is to be fo rwar d ed. The da taba se co ntains a list of e ntries — each e ntry c onta ins three items: ■ MAC (E ther ne t) ad[...]

46 C HAPTER 5: U SING THE S W ITCH D ATABASE Swit ch Dat abase En try St a te s Da ta b ase s en tr i es ca n h a ve th ree sta t es: ■ Lear ned — The Switch has plac ed the ent ry into the Switch Da tabase when a packet was r eceived fr o m an endstat ion . Note t h at : ■ Learned entr ies are r em ove d (aged out) fr om the Switch Datab ase[...]

6 U SING T RA F F IC P RIORITIZA TION Using t he t raffic pri oritiza tion ca pab ilities of your Swi tch al lows yo ur netwo rk tra f fic to be pri orit ized to ensu re th at hig h prio rity da ta is tra ns m itte d w ith m in imu m de la y . For a lis t of th e features supported b y your Switc h, please r efer to the Manageme n t Quick Refere nc[...]

48 C HAPTER 6: U SING T RA F FI C P RIOR ITIZA TION ■ Res our ce p lann ing appl ica tions — Use d by org aniza tions t hat r eq uir e p r edict able and r eli able acce s s to enter prise r es ource p lanning applic ations s uch as SAP . ■ Fin ancial app lica tions — Use d by Ac co unts depa rtme nts th at ne ed i m medi ate acce ss to lar[...]

Ho w Tr af fi c Prio r iti zati o n Wo rks 49 Y ou cannot alt er the mappi ng of the p riorities . These ar e fixed to the traf fic ty pes a s shown in Figure 1 1 . Figur e 11 IEEE 802.1D traf fic typ es Fig ure 11 illu strates I EEE 802.1D traf fic types as well as assoc iated pri orit y l evels and how th ey ar e mapped to the two supp orted tr a[...]

50 C HAPTER 6: U SING T RA F FI C P RIOR ITIZA TION Figur e 12 DSCP Service Le vel Mapping Figu r e 1 2 ill ustrates h ow DiffSer v code point (DSCP) s ervice lev els are mapped to the two T raff ic Queue s. The DSCP servi ce level of the packet i s not alter ed by the Switc h 4200. T raf fic Pr ioriti za tion and y our Swi tch The tr affi c should[...]

Tr af fi c Pr iori ti zati on and yo ur Sw itc h 51 How t raf fic is pr ocessed to pr ovide Qual ity of Serv ice A rec eived packet at the ing ress port is checked for it s DSCP and IEEE 802.1 D attribu tes to de termine t he level o f serv ice that t he packet should re c e i v e . 802.1 D packet s ar e categori zed into t he 8 traf fic class es d[...]

52 C HAPTER 6: U SING T RA F FI C P RIOR ITIZA TION somewher e else in the netwo rk and not in th e Switch 4200 . Note also tha t 802.1 D ser vice le vels a r e f ixed and c annot be altered. 3 Create Prof iles The next st ep i s to crea te a pro file, wh ich a sso ciat es classifier s with service levels. 4 A pply Qos pr of ile After a QoS p rofil[...]

7 S TA TUS M ONIT ORING AND S TA TIS TIC S This c hapter c ontains det ails of th e featur es t hat assist y ou with st atus moni toring and statistic s. For de tailed desc ript ions of the web interfac e operation s and the comma n d line i nterfac e (C LI) c omma nds that yo u requi re to manage the Swi tch please r efer to the Management I nterf[...]

54 C HAPTER 7: S TATUS M ONI T ORI NG AND S TATISTICS the sa me net wor k as th e Sw itch and can m anage the S witc h by i n-band or out -of-ba nd co nnec tion s. The RMON Gr oups The IETF defi ne gr ou ps o f Et hernet RMON s tatist ics. This sectio n descr ibes the two g roups sup ported by the Swi tch 4200 S eries, a nd de tails h ow yo u can u[...]

RMON and the Swit ch 55 addit ion, p r o bes reco rd the beh avior of yo ur ne tw ork, so th at you can analy ze the causes of pr oblems. ■ It r educ es the lo ad on t he netw ork and the mana geme nt wo rkst atio n T r aditional ne twork m ana gem ent invol ves a man age ment w orkst ation polling n etwor k dev ices a t r egu lar int ervals to g[...]

56 C HAPTER 7: S TATUS M ONI T ORI NG AND S TATISTICS Alar m Events Y ou can defi ne up to 200 alar ms for th e S witch. The ev ents th at you ca n defi ne for eac h alarm and th eir r esulti ng action s are li sted in T able 5. The D efaul t Alarm Settin gs A new or initialized Sw itch ha s the f ollow ing al arm(s) de fine d for e ach po rt: ■ [...]

RMON and the Swit ch 57 The A udit Log The Switch keeps an audit lo g o f all manageme nt user session s, pro viding a record of a v arie ty of ch a nges, in cluding ones relating to RM ON . The log c an on ly be read b y u sers at th e security access leve l u si ng an SNMP Netwo rk Ma nag eme nt appl icatio n. Each e ntr y in the log co ntain s i[...]

58 C HAPTER 7: S TATUS M ONI T ORI NG AND S TATISTICS Y ou can con figure the e mail address to w hic h you wi sh th e not ificatio ns to be sent. H ow ever , y ou ca nnot chang e th e fac tory defau lt no tifica tion mess ages fo r event ema ils. RMO N traps c onti nue to b e se nt, in a dditi on to an y em ail no tific ations you ma y re cei ve. [...]

Hardwar e Stat us M onito ring 59 Figur e 13 Example C LI scr een te xt Figur e 14 Example of an indi vidual unit sy stem summary scr een ■ Via th e w e b. On th e Web int e rf ace , a n i nd ic ati on o f a ge ne r al ha rdw a re fa il ure w ill be pr ovided thr ough th e top-lev el System Su mmary inform ation screen. Y o u shoul d refer t o th[...]

60 C HAPTER 7: S TATUS M ONI T ORI NG AND S TATISTICS Figur e 15 Example device summary web page ■ RMO N T rap See “Events” on pa ge 54 fo r detail s of th is feat ure o f your Swit ch. ■ RMO N Eve nt No tificati on. Y ou ca n co n fig u r e Ev en t N o tif i cati on fo r fa n f ai lu re; re f er t o “E mai l Notif icati on of Event s” [...]

8 S E TTI NG U P V IRTUAL LAN S Sett ing up Vi rtual LA N s (VLAN s) on you r Swi tch r edu ce s the t ime and ef fort r equir ed by many net work administ rati on tasks, and incr eases th e efficie ncy of yo ur net work. This chapter explain s mor e abou t the c oncept of V LANs and exp lains ho w the y can be imp lem ented on your Sw itch. It c o[...]

62 C HAPTER 8: S ETTING U P V IRTUAL LAN S Figur e 16 A network setup showing thr ee VLANs Benefits of VLANs The main benef it of VLANs i s th at they pr o vid e a network seg m e ntati on sys tem that is far mor e fl exible than any tr aditi onal network. Usin g V LANs also prov ides you wi th three o ther ben efits: ■ VLAN s ease th e m ove me [...]

VLAN s and Your Swit ch 63 ■ VLAN s he lp to control tra ffic W ith t radit ional netw orks, conge stion can be c ause d by broad cast traffic tha t is directe d to al l net work dev ices w hethe r th ey require it or not. V LA Ns increas e the efficien cy of your net work because eac h VLAN c an b e set u p to co nta in only those device s that [...]

64 C HAPTER 8: S ETTING U P V IRTUAL LAN S VLANs: T agged a nd Unt agged Mem bership Y ou r Swi tch su pport s 802.1Q VLA N tag ging, a syst em tha t allows t raffic for mult iple VLANs to be carried on a single ph ysical (backbone) link. When settin g up V LANs yo u nee d to und erstand wh en t o use u ntagge d and ta gged me mbe rship of VLANs. Q[...]

VLAN s and Your Swit ch 65 Conne cti ng VL ANS to Other VLANS I f the devices p laced in a VLAN need to communicate to devices in a different LAN , e ach VLA N requi re s a con nect ion to a router or Lay er 3 switchin g device. Communicatio n between VLANs can only take p lace if the y are all c onnec ted to a routin g o r Laye r 3 swi tching devi[...]

66 C HAPTER 8: S ETTING U P V IRTUAL LAN S VLAN Config uration Exam ple s This se ction c onta ins exa mpl es of sim ple V LAN configu rat ions. It descri bes ho w to se t up y our switc h to su pport si mple u ntag ged an d tagge d conn ection s. Usin g Unt agg ed Con necti ons The simp lest VLAN operates in a small network u sing a single swit ch[...]

VLAN Confi gurati on Exampl es 67 2 Add p orts to the VLA Ns Ad d p or ts 10 , 11 an d 1 2 of the Swi t ch a s un t agg ed mem be rs t o VLA N 2. Usin g 802.1Q T ag ged Con necti ons In a netwo rk where t he VLANs are d istrib uted amongst more t han one Switch , you must use 802 .1Q tagged connec tions so t hat all VLAN tra ffic can be passe d alo[...]

68 C HAPTER 8: S ETTING U P V IRTUAL LAN S 3 Add port 12 o n Sw itch 1 to the V LAN s A dd por t 12 o n Sw itch 1 as a tagge d m ember of bo th V LANs 1 and 2 so that all VLAN traf f i c is passed over t he lin k to Switc h 2. 4 Co nfi gur e t he VLANs on Swi tch 2 Define VLAN 2. VLAN 1 is the default VLAN and alrea dy exists. 5 A dd ends tati on p[...]

9 U SING A UTO M ATI C IP C ONFIGURATIO N This c hapter ex plains mor e about IP addr esses and how t he automati c conf igur ation opt ion works . It co vers th e follo wing to pics: ■ How Y our Swit ch Obtains IP In formation ■ How Auto mati c IP Conf igurati o n W orks ■ Importan t Con sideratio ns For d etailed info rmati on on se tting u[...]

70 C HAPTER 9: U SING A UTOMA TIC IP C ONFIGU RATI ON How Y our Swi tch Obtains IP In formati on Y ou can use on e of the following met hods to alloc ate IP i nform ation to yo ur Swit ch (e sse ntial i f you wish to ma nag e you r Swi tch across t he netw ork): ■ Aut omat ic I P Confi gur ation (default) — the Switch tr ies to configu re itsel[...]

How Automat ic IP Confi guration Works 71 Autom atic Process T o de tect it s IP in formati on usi ng the a utom atic con figurat ion process, the S witch goes throu gh the f ollowi ng seq uence of step s: 1 The DHC P cli ent that r e sides in t he Switch m akes up to f our attempts to contact a DHCP ser ver on t he net work request ing IP informat[...]

72 C HAPTER 9: U SING A UTOMA TIC IP C ONFIGU RATI ON Importa nt Conside ration s This se ction c onta ins som e impo rtant point s to no te wh en using the autom atic IP c onfigur ation feat ur e. The dynam ic nature of automatic ally configu red IP inform ation means that a Swit c h may change its IP ad dress whils t in use. Server Su ppor t Y ou[...]

II A PP ENDI C ES AND I NDEX App endix A C onf igur ati on R ul es App endix B Network Confi guration Exampl es App endix C I P Addressing Glossary In de x[...]

74[...]

A C ONFIGURATIO N R ULES Config uration Rul es fo r Gig a b it Eth er net G ig abi t Et hern et is de sig ned t o run ov er se ver al me di a: ■ Singl e-mode fibe r opt ic cab le, w ith conn ect ions up to 5 km (3.1 mi les). S uppor t for d istances o ver 5 km is supp orted d epe ndin g on t he mo dule sp ecifi cation. ■ Mul timode fibe r opt i[...]

76 A PPENDIX A: C ON FI GUR A TI ON R ULES Config uration Rul es fo r Fas t E th er ne t The t opolo gy rule s for 100 M bps Fa st Ether net are slight ly different to those f or 10 M bps E ther n et. Figu r e 20 illust rates th e key t opology r ules and pr o vid es examples o f how they all ow for large-s cale Fas t Ethernet netw orks. Figur e 20[...]

Confi gurati on Rul es f or F ast E therne t 77 colla psed backbo ne). F or e xamp le, a 225 m ( 738 ft) fib er link from a r ep eater to a r out er or sw itch, plus a 100 m (32 8 ft) UTP link from a r ep eater out to t he endst ation s. Confi gur ation Rule s wit h Fu ll Du ple x The S witc h provides fu ll dupl ex support f or a ll its por ts, in[...]

78 A PPENDIX A: C ON FI GUR A TI ON R ULES[...]

B N ETW ORK C ONFIGURATI ON E XAMPLES Th is ch ap te r co n tai n s th e fol lo wi ng s e ct io ns : ■ Simple Net w or k Configurat ion Examples ■ Segmen tation Switch Ex ample ■ Collapsed Backbone Switc h Example ■ Desktop Swit ch Example ■ Adv anced Netwo rk Co nf igurati on Ex ample s ■ Improvin g the Re silien ce of Y o ur Netwo rk [...]

80 A PPENDIX B: N ETWORK C O NF IGU R AT ION E XAM PLE S Sim ple Netw ork Config uration Exam ple s The foll ow ing illu strations show some simp le examples of how the Switch 4200 f amil y and 4900 f amil y can be us ed in y our ne twor k. Segm entati on S wi tch Exam ple The example i n Figu r e 21 shows how a 10/100 Swit ch such as the Switc h 4[...]

Simpl e Network Conf igura tion Ex amples 81 Coll aps ed Back bone Switc h Exa m ple The example i n Figu r e 2 2 shows how a Switch 4 200 stack can ac t as a backb one f or bo th sha r ed and switch ed net wor k segment s. Figur e 22 Using the Swit ch 4200 as a collaps ed backbone Switch 4200 stack Endstations on switched 10 Mbps connections Endst[...]

82 A PPENDIX B: N ETWORK C O NF IGU R AT ION E XAM PLE S D eskt op S wi tch Exam ple The example i n Figu r e 2 3 sh ows ho w a Sw itch 42 00 ca n be used for a group of user s tha t require dedicat ed 10 M bps or 100 Mbps con nectio ns to th e deskto p. Th e Swit ch 420 0 st ack has a 1000 BASE -T Mo dule f itted tha t allow s it to provide a Giga[...]

Advanc ed Network Conf igura tion Ex amples 83 Ad vance d Ne twor k Config uration Exam ple s This sec tion s hows some netwo rk examples that il lustr ate how you can set up y our ne twor k for o ptimum perfor manc e using som e of th e feature s suppor ted by your Swi tch. Impr oving t he Res ilie nce of Y our Ne twork Figu r e 2 4 show s how you[...]

84 A PPENDIX B: N ETWORK C O NF IGU R AT ION E XAM PLE S Enhanc ing t h e Perform ance o f Y ou r Ne twork Figu r e 2 5 show s how you ca n se t your n etwor k up to e nhance its perfor mance . All port s ar e auto-neg otiatin g and smart auto- sensin g and will th eref or e pass dat a across the netw ork at the opt imum availabl e speed a nd dupl [...]

C IP A DD R ESSIN G This ch ap ter provid es som e background detai l on the IP i nfor matio n tha t needs to be assi gned to you r Switch to ena ble you to man age it acr oss a networ k. The topic s cover ed ar e: ■ IP Addresses ■ Subn ets and S ubne t Masks ■ Def ault Ga teways IP ad dress ing is a vast topic a nd t here are w hite paper s [...]

86 A PPENDIX C: IP A DDR ESSING 192.16 8.10 0. X (wh ere X is a nu mber betw een 1 a nd 25 4) wi th a su bnet mask 25 5.25 5.25 5.0. If yo u are usin g SLIP , u se the def ault SLIP add r ess of 192.16 8.10 1.1 with a su bnet mask o f 255. 255 .255.0. These su ggested I P addres ses are part of a group of I P addresses that have b een set asid e sp[...]

IP A ddre sses 87 Dotted D ecim al Notation The actu al IP addr ess is a 3 2-bit nu mber that is sto red in binary f ormat. These 32 bi ts are segm ented into 4 groups of 8 bit s — each g r oup is r eferred to as a fi eld or a n oc te t . Decimal notat ion convert s the val ue of each fiel d i nto a decimal number , and t he fields ar e se parate[...]

88 A PPENDIX C: IP A DDR ESSING Subne ts and Subnet Masks Y ou can divide your IP netw ork into sub- netw orks also kn own as subn ets. Supp ort for subne ts is imp ortant bec ause the nu mber of bit s assigned t o the dev ice pa rt of an I P addr ess limit s the numbe r of devi ces that m ay be addr essed on an y given network. For ex ample, a Cla[...]

Sub nets and Subn et Mask s 89 As sho wn in this ex ample , the 32 bits of an I P addr ess and subn et mask are u sually w ritten using an integ er shortha nd. T his n otation t ranslate s f our con sec ut iv e 8- bi t gr oup s (oc te t s) i nto f ou r in t ege rs th at r ang e fr om 0 thro ugh 255 . The su bnet mask i n the e xam ple is w ritten a[...]

90 A PPENDIX C: IP A DDR ESSING The sub net mask 25 5.25 5.255.2 55 is r eser ved as the defau lt broad cast addre ss. D e fau l t Ga te w ay s A gate way i s a dev ice on you r ne two rk wh ich is use d to forwa rd IP pac kets to a rem ote desti n atio n. An alternati ve name for a gateway is a Router . “Remo te” r efe rs to a destina tion d e[...]

G LOSSARY 3Com N etwor k Supe rvis or The 3C om netwo rk m anageme nt ap plication used t o ma nage 3Com ’ s netw orking solutions. 10B ASE -T The IEEE specif ication fo r 10 Mbps Ethernet over Category 3, 4 or 5 twist ed pai r ca ble. 100B A SE-FX The IEEE sp ecific ation f or 100 Mbps Fast Ethernet over fiber -optic cable. 100BA SE -TX The IEEE[...]

92 G LOSSARY Fast E ther net is 100 Mbp s, and the bandw idth of Gigabi t Eth erne t i s 10 00 Mbps . baud Th e signalli n g rat e of a line, that is, the number o f transi tions (volta ge or frequ ency chan ges) m ade pe r seco nd. Also k now n as line speed . BOOTP The BOO TP protocol a llows you t o automa tically map an IP a ddress to a giv en [...]

93 DHCP Dyn ami c H ost Cont rol Protocol. A prot ocol th at le ts you cen trally manag e a nd au tomate t he assign ment of Int erne t Protoco l (IP) addresses in a n org aniza tion's n etwor k . DNS Do main Name System. This s ystem maps a numerical In ternet Pr otocol (IP) addr ess to a mor e meanin g f ul and easy-to -r emember nam e. When[...]

94 G LOSSARY gat eway See rou ter . GBIC Gigabit In terface Conv erter . Giga bit Eth ernet I EEE standar d 802.3z fo r 1000 Mbps Ethernet; i t is compatible wit h existing 10/100 M bps Ether net stand ar d s. half du ple x A sy stem that all ows pac kets to t ransmi tted an d receive d, but not at the sam e time. C ontrast with full du plex . hub [...]

95 Inte rne t Grou p Manage ment Pr otocol Inter ne t Gr ou p Manage me nt Pr o tocol (IGMP) is a protoco l t hat runs betwe en hosts an d their im mediate neig hboring multi c ast rout ers. The protoco l allows a host to inf orm it s local router that it w ishes to r ec eive transm issions addresse d to a specific multi cast group. Ba sed on group[...]

96 G LOSSARY lo op An event t hat occur s when two network devi ces are connected by mor e than one pa th, ther eby causing pa ckets to r epeatedly cyc le ar o und the netwo rk and not r eac h their d es tination. MAC Media Access Contr ol. A pr o to col specified by the IEEE fo r determ ining whic h devices hav e access to a ne twork at any one ti[...]

97 POS T Power On Se lf T est. An intern a l test that a Switch carries out wh en it is powered- up. QoS Profile Con si sts of multiple sets of rul es (classi f ier pl u s ser vice level combin ations) . The QoS profil e is assig ned to a port(s) . pr oto col A set of ru les for c omm unica tion be tween devi ces on a n etwo rk. The ru les d ic tat[...]

98 G LOSSARY st andar d servi ce level s, for ex ample, best e ffort , busines s crit ical, ne twork control, a nd so on. SLIP Se rial Li ne Int erne t P rot o col. A protoc ol tha t allow s IP to run over a serial line (con sole po rt) conne ction . SMTP Sim ple Ma il T ransfer Protocol. An IETF standard protoc ol used for tran sferri ng mail ac r[...]

99 TC P rel a tes to th e c on te n t o f th e d a ta tra v e lli ng thro u gh a ne two rk — ensu ring that th e infor mation sent ar rives in one piece when it r eaches i ts destinat ion. IP r elates to the addr ess of the endst ati on to which d ata is bei ng sen t, as w ell as the address of the de stination n etwo rk. Te l n e t A TCP/IP appl[...]

100 G LOSSARY[...]

I NDEX Numbers 802.1 D prio rity le vel s 48 tr affic cl as si fica ti on 4 8 802.1 Q t aggin g 64 A addr esses cla sses 87 IP 85 aggr eg ated l inks 14, 22 ex am pl e 25 agin g time, definit ion 4 6 alar m eve nts 56 alar m se tting s, def ault 56 Alar ms (RMON gr oup) 54, 55 audi t log 57 auto- IP 14, 70 autom ati c IP co nfigur atio n 14, 7 0 au[...]

102 I NDEX IGM P mu ltic a st fi lter in g 3 0 Inte rnet ad dres ses 85 In terN IC 86 IP ( Internet Pr otocol) ad dres ses 86 IP add res s 14, 70, 85 clas se s of 87 defi ned 86 deri vati on 86 divi sion o f networ k and host 86 exam ple 88 obtai ning 86 subnet mask 8 8 subnet work por tion 88 IP m ult icas t ad dres sing 27 IP ro utin g ad dres s [...]

I NDEX 103 Root Por t 37 using on a networ k with mul tiple VL ANs 42 su bnet mask 88 defi ned 88 exam ple 88 numbe ring 89 su bnets 88 su bnetwork ing defi ned 88 su bnet mask 88 su b-networ ks. See su bnets Switc h Databas e 45 T topol ogy rul es for Fast E thernet 76 topol ogy rul es wit h full dupl ex 77 traf fic c l as sif icati on 802.1D 48 t[...]