{"id":37988,"date":"2019-10-31T22:21:01","date_gmt":"2019-10-31T19:21:01","guid":{"rendered":"https:\/\/prohoster.info\/blog\/trening-cisco-200-125-ccna-v3-0-den-37-stp-vybor-root-bridge-funktsii-portfast-i-bpdu-guard-chast-2\/"},"modified":"2019-10-31T22:21:01","modified_gmt":"2019-10-31T19:21:01","slug":"trening-cisco-200-125-ccna-v3-0-den-37-stp-vybor-root-bridge-funktsii-portfast-i-bpdu-guard-chast-2","status":"publish","type":"post","link":"https:\/\/prohoster.info\/ro\/blog\/administrirovanie\/trening-cisco-200-125-ccna-v3-0-den-37-stp-vybor-root-bridge-funktsii-portfast-i-bpdu-guard-chast-2","title":{"rendered":"Antrenament Cisco 200-125 CCNA v3.0. Ziua 37. STP: alegerea Root Bridge, func\u021biile PortFast \u0219i BPDU guard. Partea 2","gt_translate_keys":[{"key":"rendered","format":"text"}]},"content":{"rendered":"

S\u0103 presupunem c\u0103 STP se afl\u0103 \u00een starea sa de convergen\u021b\u0103. Ce se va \u00eent\u00e2mpla dac\u0103 iau un cablu \u0219i conectez switch-ul N direct la switch-ul principal A? Root Bridge va \"vedea\" c\u0103 a ap\u0103rut un nou port activat \u0219i va trimite BPDU prin acesta. <\/p>\n

\"Antrenament
\n
\nSwitch-ul N, primind acest cadru cu cost zero, va determina costul rutei prin noul port ca fiind 0+19=19, av\u00e2nd \u00een vedere c\u0103 costul portului s\u0103u principal este 76. Dup\u0103 aceea, portul switch-ului N, care anterior era \u00een stare dezactivat\u0103, va trece prin toate etapele de tranzi\u021bie \u0219i se va schimba \u00een modul de transmisie abia dup\u0103 50 de secunde. Dac\u0103 la acest switch sunt conectate alte dispozitive, toate acestea vor pierde conexiunea cu switch-ul principal \u0219i cu re\u021beaua \u00een general timp de 50 de secunde. <\/a><\/noindex><\/p>\n

La fel procedeaz\u0103 \u0219i switch-ul G, care prime\u0219te de la switch-ul N un cadru BPDU cu notificarea costului de 19. Acesta \u00ee\u0219i schimb\u0103 costul portului desemnat la 19+19=38 \u0219i \u00eel reprogrameaz\u0103 ca noul s\u0103u port principal, deoarece costul vechiului s\u0103u Root Port este 57, ceea ce este mai mare dec\u00e2t 38. Astfel, toate etapele de reprograme a porturilor, care dureaz\u0103 50 de secunde, \u00eencep din nou \u0219i, \u00een final, \u00eentreaga re\u021bea se va pr\u0103bu\u0219i. <\/p>\n

\"Antrenament
\n
\nAcum s\u0103 examin\u0103m ce se va \u00eent\u00e2mpla \u00een situa\u021bii similare utiliz\u00e2nd RSTP. Switch-ul principal va trimite la fel BPDU switch-ului N care s-a conectat la el, dar imediat dup\u0103 aceea \u00ee\u0219i va bloca portul. Primind acest cadru, switch-ul N va determina c\u0103 aceast\u0103 rut\u0103 are un cost mai mic dec\u00e2t portul s\u0103u principal \u0219i \u00eel va bloca instantaneu. Dup\u0103 aceea, N va trimite switch-ului principal o propunere de deschidere a unui nou port, deoarece costul s\u0103u este mai mic dec\u00e2t costul deja existent al portului principal. Dup\u0103 ce switch-ul principal va accepta aceast\u0103 solicitare, el va debloca portul s\u0103u \u0219i va trimite un acord switch-ului N, dup\u0103 care acesta din urm\u0103 va face noul port s\u0103 fie portul s\u0103u principal. <\/p>\n

\"Antrenament
\n
\nAstfel, datorit\u0103 mecanismului Proposal\/Agreement, reprogramele portului principal se vor realiza practic instantaneu \u0219i toate dispozitivele conectate la switch-ul N nu vor pierde conexiunea cu re\u021beaua.
\nDup\u0103 ce a desemnat noul Root Port, switch-ul N va transforma vechiul port principal \u00eentr-un port alternativ. Aceea\u0219i situa\u021bie se va \u00eent\u00e2mpla cu switch-ul G - va schimba mesaje Proposal\/Agreement cu switch-ul N, va desemna un nou port principal \u0219i va bloca celelalte porturi. Procesul va continua \u00een segmentul urm\u0103tor al re\u021belei cu switch-ul F. <\/p>\n

\"Antrenament
\n
\nSwitch-ul F, analiz\u00e2nd costurile, va observa c\u0103 ruta c\u0103tre switch-ul r\u0103d\u0103cin\u0103 prin portul inferior va costa 57, \u00een timp ce ruta deja existent\u0103 prin portul superior cost\u0103 38, \u0219i va l\u0103sa totul a\u0219a cum este. Afl\u00e2nd despre asta, switch-ul G va bloca portul \u00eendreptat c\u0103tre F \u0219i va redirec\u021biona traficul c\u0103tre switch-ul r\u0103d\u0103cin\u0103 prin noua rut\u0103 G-H-A. <\/p>\n

P\u00e2n\u0103 c\u00e2nd switch-ul F nu va primi o Propunere\/Contract de la switch-ul G, el va men\u021bine portul s\u0103u inferior blocat pentru a preveni formarea buclelor. A\u0219adar, observa\u021bi c\u0103 RSTP este un protocol foarte rapid care nu creeaz\u0103 probleme \u00een re\u021bea specifice STP.
\nAcum s\u0103 trecem la examinarea comenzilor. Trebuie s\u0103 intra\u021bi \u00een modul de configurare global\u0103 a switch-ului \u0219i s\u0103 alege\u021bi modul PVST sau RPVST folosind comanda spanning-tree mode . Apoi, trebuie s\u0103 decide\u021bi cum s\u0103 modifica\u021bi prioritatea unei VLAN specifice. Acest lucru se face prin comanda spanning-tree vlan priority . Din ultimul tutorial video ar trebui s\u0103-\u021bi aminte\u0219ti c\u0103 prioritatea este un num\u0103r, multiplu de 4096, iar \u00een mod implicit, acest num\u0103r este 32768 plus num\u0103rul re\u021belei VLAN. Dac\u0103 ai ales VLAN1, atunci prioritatea implicit\u0103 va fi 32768+1= 32769. <\/p>\n

\"Antrenament
\n
\nDe ce ar putea fi necesar\u0103 modificarea priorit\u0103\u021bii re\u021belelor? \u0218tim c\u0103 BID const\u0103 \u00eentr-o valoare numeric\u0103 de prioritate \u0219i MAC-adresa. MAC-adresa dispozitivului nu poate fi schimbat\u0103, are o valoare fix\u0103, a\u0219a c\u0103 doar m\u0103rimea priorit\u0103\u021bii poate fi modificat\u0103.<\/p>\n

S\u0103 presupunem c\u0103 exist\u0103 o re\u021bea mare unde toate dispozitivele Cisco sunt conectate \u00eentr-un mod circular. \u00cen acest caz, PVST este activat implicit, deci sistemul va alege switch-ul r\u0103d\u0103cin\u0103. Dac\u0103 toate dispozitivele au aceea\u0219i prioritate, switch-ul cu cea mai veche MAC-adres\u0103 va avea prioritate. Totu\u0219i, aceasta ar putea fi un switch de 10-12 ani, un model \u00eenvechit, care nu mai are puterea \u0219i performan\u021ba necesar\u0103 pentru a \"conduce\" o re\u021bea at\u00e2t de extins\u0103.
\n\u00cen acela\u0219i timp, \u00een re\u021beaua ta ar putea fi un switch nou de c\u00e2teva mii de dolari, care din cauza unui num\u0103r MAC mai mare este obligat s\u0103 \"se supun\u0103\" unui switch vechi de c\u00e2teva sute de dolari. Dac\u0103 switch-ul vechi devine switch-ul r\u0103d\u0103cin\u0103, aceasta indic\u0103 o eroare sever\u0103 de design \u00een re\u021bea.<\/p>\n

Prin urmare, trebuie s\u0103 accesa\u021bi set\u0103rile noului switch \u0219i s\u0103-i atribui\u021bi o valoare minim\u0103 a priorit\u0103\u021bii, de exemplu, 0. C\u00e2nd se utilizeaz\u0103 VLAN1, valoarea total\u0103 a priorit\u0103\u021bii va fi 0+1=1, iar toate celelalte dispozitive vor considera constant acest switch ca fiind switch-ul r\u0103d\u0103cin\u0103.<\/p>\n

Acum s\u0103 ne imagin\u0103m o astfel de situa\u021bie. Dac\u0103 switch-ul r\u0103d\u0103cin\u0103 devine inaccesibil dintr-un anumit motiv, s-ar putea s\u0103 dori\u021bi ca noul switch r\u0103d\u0103cin\u0103 s\u0103 nu fie orice switch cu o prioritate mai mic\u0103, ci un anumit switch cu cele mai bune func\u021bii de re\u021bea. \u00cen acest caz, \u00een set\u0103rile Root Bridge, se folose\u0219te comanda care desemneaz\u0103 switch-uri r\u0103d\u0103cin\u0103 principale \u0219i secundare: spanning-tree vlan root . Valoarea priorit\u0103\u021bii pentru switch-ul principal va fi 32768 \u2013 4096 \u2013 4096 = 24576. Pentru switch-ul secundar, aceasta se calculeaz\u0103 prin formula 32768 \u2013 4096 = 28672.<\/p>\n

Nu este nevoie s\u0103 introduce\u021bi aceste numere manual \u2013 sistemul le va genera automat pentru dumneavoastr\u0103. Astfel, switch-ul cu prioritate 24576 va fi switch-ul r\u0103d\u0103cin\u0103, iar \u00een cazul \u00een care acesta devine inaccesibil, switch-ul cu prioritate 28672 va prelua aceast\u0103 func\u021bie, av\u00e2nd \u00een vedere c\u0103 prioritatea tuturor celorlalte switch-uri este, \u00een mod implicit, de cel pu\u021bin 32768. Asta este procedura dac\u0103 nu dori\u021bi ca sistemul s\u0103 desemneze automat switch-ul r\u0103d\u0103cin\u0103. <\/p>\n

Dac\u0103 dori\u021bi s\u0103 vizualiza\u021bi set\u0103rile protocolului STP, trebuie s\u0103 folosi\u021bi comanda show spanning-tree summary. Acum s\u0103 examin\u0103m toate subiectele studiate ast\u0103zi folosind Packet Tracer. Folosesc o topologie de re\u021bea cu 4 switch-uri model 2690, dar acest lucru nu conteaz\u0103, deoarece toate modelele de switch-uri Cisco suport\u0103 STP. Ele sunt conectate \u00eentre ele astfel \u00eenc\u00e2t re\u021beaua formeaz\u0103 un circuit \u00eenchis. <\/p>\n

\u00cen mod implicit, dispozitivele Cisco func\u021bioneaz\u0103 \u00een modul PSTV+, adic\u0103 pentru convergen\u021b\u0103, fiecare port va avea nevoie de maximum 20 de secunde. Panoul de simulare permite vizualizarea transmiterii traficului \u0219i examinarea parametrilor de func\u021bionare ai re\u021belei create.<\/p>\n

\"Antrenament
\n
\nVede\u021bi cum arat\u0103 un cadru STP BPDU. Dac\u0103 observa\u021bi denumirea versiunii 0, \u00eenseamn\u0103 c\u0103 este vorba de STP, deoarece pentru RSTP se folose\u0219te versiunea 2. De asemenea, este prezentat \u0219i ID-ul r\u0103d\u0103cinii, compus din prioritatea \u0219i adresa MAC a switch-ului r\u0103d\u0103cin\u0103, precum \u0219i ID-ul bridge-ului corespunz\u0103tor. <\/p>\n

\"Antrenament
\n
\nAceste valori sunt egale, deoarece costul drumului c\u0103tre switch-ul r\u0103d\u0103cin\u0103 pentru SW0 este 0, prin urmare, acesta este el \u00eensu\u0219i switch-ul r\u0103d\u0103cin\u0103. A\u0219adar, dup\u0103 activarea switch-urilor prin utilizarea STP, a avut loc o alegere automat\u0103 a Root Bridge \u0219i re\u021beaua a \u00eenceput s\u0103 func\u021bioneze. Observa\u021bi c\u0103 pentru a preveni buclele, portul superior Fa0\/2 al switch-ului SW2 a fost trecut \u00een starea Blocking, dar ceea ce indic\u0103 culoarea portocalie a markerului. <\/p>\n

\"Antrenament
\n
\nS\u0103 trecem la consola de set\u0103ri a switch-ului SW0 \u0219i s\u0103 folosim o pereche de comenzi. Prima este comanda show spanning-tree, dup\u0103 ce o introducem, informa\u021biile despre modul PSTV+ pentru re\u021beaua VLAN1 vor fi afi\u0219ate pe ecran. Dac\u0103 vom utiliza mai multe VLAN-uri, \u00een partea de jos a ferestrei va ap\u0103rea un alt bloc de informa\u021bii pentru re\u021beaua a doua \u0219i urm\u0103toarele utilizate. <\/p>\n

\"Antrenament
\n
\nObserva\u021bi c\u0103 protocolul STP este disponibil conform standardului IEEE, ceea ce \u00eenseamn\u0103 utilizarea PVSTP+. Tehnic vorbind, aceasta nu este standardul .1d. Aici sunt prezentate \u0219i informa\u021biile despre Root ID: prioritate 32769, adresa MAC a dispozitivului r\u0103d\u0103cin\u0103, costul 19 etc. Apoi urmeaz\u0103 informa\u021biile despre Bridge ID, \u00een care este detaliat\u0103 valoarea priorit\u0103\u021bii 32768 +1, \u0219i se prezint\u0103 o alt\u0103 adres\u0103 MAC. A\u0219a cum observa\u021bi, m-am \u00een\u0219elat \u2014 switch-ul SW0 nu este switch-ul r\u0103d\u0103cin\u0103, switch-ul r\u0103d\u0103cin\u0103 are o alt\u0103 adres\u0103 MAC, prezentat\u0103 \u00een parametrii Root ID. Cred c\u0103 acest lucru se datoreaz\u0103 faptului c\u0103 SW0 a primit un cadru BPDU cu informa\u021bia c\u0103 un anumit switch din re\u021bea are con\u021binuturi mai mari pentru a juca rolul de r\u0103d\u0103cin\u0103. Acum vom analiza acest lucru.<\/p>\n

(noteaz\u0103 traduc\u0103torul: Root ID \u2013 identificatorul switch-ului r\u0103d\u0103cin\u0103, identic pentru toate dispozitivele din aceea\u0219i re\u021bea VLAN, oper\u00e2nd pe protocolul STP, Bridge ID \u2013 identificatorul switch-ului local \u00een cadrul Root Bridge, care poate fi diferit pentru diferite switch-uri \u0219i VLAN-uri.)<\/p>\n

Un alt aspect care indic\u0103 faptul c\u0103 SW0 nu este switch-ul r\u0103d\u0103cin\u0103 \u2013 este c\u0103 switch-ul r\u0103d\u0103cin\u0103 nu are Root Port, iar \u00een acest caz exist\u0103 at\u00e2t Root Port, c\u00e2t \u0219i Designated Port, aflate \u00een stare de forwarding. De asemenea, observa\u021bi tipul conexiunii p2p, sau \u201epunti la punct\u201d. Aceasta \u00eenseamn\u0103 c\u0103 porturile fa0\/1 \u0219i fa0\/2 sunt conectate direct la switch-urile vecine.
\nDac\u0103 un port ar fi conectat la hub, tipul de conexiune ar fi denumit shared, despre care vom discuta mai t\u00e2rziu. Dac\u0103 introduc comanda pentru a vizualiza informa\u021biile finale show spanning-tree summary, vom observa c\u0103 acest switch este \u00een modul PVSTP, urmat de enumerarea func\u021biilor de port indisponibile. <\/p>\n

\"Antrenament
\n
\nMai jos este prezentat starea \u0219i num\u0103rul de porturi care deservesc VLAN1: blocking 0, listening 0, learning 0, \u00een stare de forwarding se afl\u0103 2 porturi \u00een modul STP.
\n\u00cenainte de a trece la switch-ul SW2, s\u0103 ne uit\u0103m la configura\u021biile switch-ului SW1. Pentru aceasta, folosim aceea\u0219i comand\u0103 show spanning-tree.<\/p>\n

\"Antrenament
\n
\nObserva\u021bi c\u0103 adresa MAC a Root ID-ului pentru switch-ul SW1 este aceea\u0219i ca \u0219i cea a SW0, deoarece toate dispozitivele din re\u021bea primesc aceea\u0219i adres\u0103 a dispozitivului Root Bridge \u00een momentul \u00eent\u00e2lnirii, datorit\u0103 \u00eencrederii \u00een alegerea efectuat\u0103 de protocolul STP. Dup\u0103 cum vede\u021bi, SW1 este switch-ul r\u0103d\u0103cin\u0103, deoarece adresele Root ID \u0219i Bridge ID coincid. De asemenea, aici se afl\u0103 un mesaj \"acest switch este switch-ul r\u0103d\u0103cin\u0103\". <\/p>\n

Un alt semn al switch-ului r\u0103d\u0103cin\u0103 este c\u0103 nu are porturi Root, ambele porturi fiind desemnate ca Designated. Dac\u0103 toate porturile sunt prezentate ca Designated \u0219i se afl\u0103 \u00een stare de forwarding, \u00een fa\u021ba dumneavoastr\u0103 se afl\u0103 un switch r\u0103d\u0103cin\u0103. <\/p>\n

Switch-ul SW3 con\u021bine informa\u021bii similare, iar acum trec la SW2, deoarece unul dintre porturile sale se afl\u0103 \u00een stare de Blocking. Folosesc comanda show spanning-tree \u0219i vedem c\u0103 informa\u021biile Root ID \u0219i valoarea prioritat\u0103 sunt acelea\u0219i ca \u0219i cele ale celorlalte switch-uri.
\nMai departe se indic\u0103 faptul c\u0103 unul dintre porturi este Alternative. S\u0103 nu v\u0103 deranjeze acest lucru, standardul 802.1d \u00eel nume\u0219te Blocking Port, iar \u00een PVSTP un port blocat este \u00eentotdeauna denumit Alternative. A\u0219adar, acest port alternativ Fa0\/2 se afl\u0103 \u00een stare blocat\u0103, iar portul Fa0\/1 func\u021bioneaz\u0103 ca Root Port. <\/p>\n

Portul blocat se afl\u0103 \u00een segmentul de re\u021bea \u00eentre switch-ul SW0 \u0219i switch-ul SW2, ceea ce ne ajut\u0103 s\u0103 evit\u0103m formarea unui loop. A\u0219a cum vede\u021bi, switch-urile folosesc o conexiune tip p2p, deoarece nu sunt conectate alte dispozitive. <\/p>\n

\"Antrenament
\n
\nAvem o re\u021bea care converte\u0219te prin protocolul STP. Acum voi lua un cablu \u0219i voi conecta switch-ul SW2 direct cu switch-ul cap SW1. Dup\u0103 aceasta, toate porturile SW2 vor fi marcate cu semne portocalii. <\/p>\n

\"Antrenament
\n
\nDac\u0103 folosim comanda show spanning-tree summary, vom observa c\u0103 la \u00eenceput cele dou\u0103 porturi sunt \u00een starea Listening, apoi trec \u00een starea Learning \u0219i, \u00een c\u00e2teva secunde, \u00een starea Forwarding, iar culoarea markerului devine verde. Dac\u0103 acum introducem comanda show spanning-tree, se poate vedea c\u0103 Fa0\/1, care anterior era Root-port, a trecut acum \u00een starea de blocare \u0219i a devenit Alternative-port. <\/p>\n

\"Antrenament
\n
\nPortul Fa0\/3, la care este conectat cablul switch-ului root, a devenit Root-port, iar portul Fa0\/2 s-a transformat \u00een Designated-port. S\u0103 examin\u0103m din nou procesul de convergen\u021b\u0103. Voi deconecta cablul SW2-SW1 \u0219i m\u0103 voi \u00eentoarce la topologia anterioar\u0103. Observa\u021bi c\u0103 porturile SW2 sunt ini\u021bial blocate \u0219i devin din nou portocalii, apoi trec succesiv prin st\u0103rile Listening \u0219i Learning \u0219i ajung \u00een starea Forwarding. \u00cen acest timp, un port devine verde, iar cel\u0103lalt, conectat la switch-ul SW0, r\u0103m\u00e2ne portocaliu. Procesul de convergen\u021b\u0103 a durat destul de mult, acestea sunt costurile func\u021bion\u0103rii STP.<\/p>\n

\"Antrenament
\n
\nAcum s\u0103 analiz\u0103m cum func\u021bioneaz\u0103 RSTP. S\u0103 \u00eencepem cu switch-ul SW2 \u0219i s\u0103 introducem \u00een set\u0103rile sale comanda spanning-tree mode rapid-pvst. Aceast\u0103 comand\u0103 are doar dou\u0103 variante de parametri: pvst \u0219i rapid-pvst, eu voi folosi pe a doua. Dup\u0103 introducerea comenzii, switch-ul trece \u00een modul RPVST, ceea ce poate fi verificat cu comanda show spanning-tree. <\/p>\n

\"Antrenament
\n
\nLa \u00eenceput, ve\u021bi vedea un mesaj c\u0103 acum func\u021bioneaz\u0103 protocolul RSTP. Totul cel\u0103lalt a r\u0103mas neschimbat. Apoi, trebuie s\u0103 fac acela\u0219i lucru pentru toate celelalte dispozitive, iar configurarea RSTP este complet\u0103. S\u0103 analiz\u0103m func\u021bionarea acestui protocol a\u0219a cum am f\u0103cut pentru STP.<\/p>\n

Conectez din nou switch-ul SW2 direct la switch-ul root SW1 \u2013 s\u0103 vedem c\u00e2t de repede se va produce convergen\u021ba. Introduc comanda show spanning-tree summary \u0219i v\u0103d c\u0103 dou\u0103 porturi ale switch-ului sunt \u00een starea Blocking, iar 1 \u00een starea Forwarding. <\/p>\n

\"Antrenament
\n
\nObserva\u021bi c\u0103 convergen\u021ba s-a realizat practic instantaneu, a\u0219a c\u0103 pute\u021bi judeca c\u00e2t de repede este RSTP \u00een compara\u021bie cu STP. \u00cen continuare, putem folosi comanda spanning-tree portfast default, care va schimba toate porturile switch-ului \u00een modul portfast implicit. Aceasta este relevant\u0103 \u00een cazul \u00een care majoritatea porturilor switch-ului sunt Edge-ports, conectate direct la gazde. Dac\u0103 avem un port care nu este Edge, \u00eel configur\u0103m \u00eenapoi \u00een modul spanning-tree. <\/p>\n

Pentru configurarea lucrului cu VLAN, se poate folosi comanda spanning-tree vlan cu parametrii priority (setea prioritatea switch-ului pentru spanning-tree) sau root (aloc\u0103 switch-ul dreptul de root). Folosim comanda spanning-tree vlan 1 priority, specific\u00e2nd ca prioritate orice num\u0103r care este multiplu de 4096, \u00een intervalul de la 0 la 61440. Astfel, putem schimba manual prioritatea oric\u0103rei VLAN. <\/p>\n

Se poate introduce comanda spanning-tree vlan 1 root cu parametrii primary sau secondary pentru a configura portul root principal sau de rezerv\u0103 pentru o re\u021bea specific\u0103. Dac\u0103 folosesc spanning-tree vlan 1 root primary, acest port va fi principalul port root pentru re\u021beaua VLAN1. <\/p>\n

Voi introduce comanda show spanning-tree, iar noi vom observa c\u0103 acest switch SW2 are prioritatea 24577, adresele MAC ale Root ID \u0219i Bridge ID coincid, ceea ce \u00eenseamn\u0103 c\u0103 acum a devenit switch-ul root. <\/p>\n

\"Antrenament
\n
\nVede\u021bi c\u00e2t de rapid s-a realizat convergen\u021ba \u0219i schimbarea rolurilor switch-urilor. Acum voi anula rolul de switch principal cu comanda no spanning-tree vlan 1 root primary, dup\u0103 care prioritatea sa va reveni la valoarea anterioar\u0103 32769, iar rolul switch-ului root va reveni la SW1. <\/p>\n

S\u0103 vedem cum func\u021bioneaz\u0103 portfast. Voi introduce comanda int f0\/1, voi accesa set\u0103rile acestui port \u0219i voi folosi comanda spanning-tree, dup\u0103 care sistemul va oferi sugestii pentru valorile parametrelor. <\/p>\n

\"Antrenament
\n
\nApoi voi folosi comanda spanning-tree portfast, care poate fi introdus\u0103 cu parametrii disable (dezactiveaz\u0103 func\u021bia portfast pentru acest port) sau trunk (activeaz\u0103 func\u021bia portfast pentru acest port chiar \u0219i \u00een modul trunk). <\/p>\n

Dac\u0103 introducem spanning-tree portfast, func\u021bia se va activa pur \u0219i simplu pe acest port. Pentru a activa func\u021bia BPDU Guard, este nevoie de comanda spanning-tree bpduguard enable, iar comanda spanning-tree bpduguard disable dezactiveaz\u0103 aceast\u0103 func\u021bie. <\/p>\n

Voi vorbi rapid despre \u00eenc\u0103 un aspect. Dac\u0103 pentru VLAN1 interfa\u021ba switch-ului SW2 \u00een direc\u021bia SW3 este blocat\u0103, atunci \u00een func\u021bie de alte set\u0103ri pentru un alt VLAN, de exemplu, VLAN2, aceast\u0103 interfa\u021b\u0103 poate deveni portul root. Astfel, \u00een sistem se poate implementa un mecanism de \u00eenc\u0103rcare a traficului \u2013 \u00eentr-un caz acest segment de re\u021bea nu este utilizat, \u00een altul \u2013 este utilizat. <\/p>\n

Voi ar\u0103ta ce se \u00eent\u00e2mpl\u0103 c\u00e2nd la conectarea unui hub avem un interfa\u021b\u0103 shared. Voi ad\u0103uga hub-ul \u00een schem\u0103 \u0219i \u00eel voi conecta la switch-ul SW2 cu dou\u0103 cabluri. <\/p>\n

\"Antrenament
\n
\nComanda show spanning-tree va reflecta urm\u0103toarea imagine. <\/p>\n

\"Antrenament
\n
\nFa0\/5 (portul din col\u021bul st\u00e2ng jos al switch-ului) devine port de rezerv\u0103, iar portul Fa0\/4 (portul din col\u021bul drept jos al switch-ului) devine port desemnat. Tipul ambelor porturi este comun, sau shared. Aceasta \u00eenseamn\u0103 c\u0103 segmentul interfe\u021belor hub-switch este o re\u021bea comun\u0103. <\/p>\n

Datorit\u0103 utiliz\u0103rii RSTP, am ob\u021binut o separare \u00eentre porturile alternative \u0219i cele de rezerv\u0103. Dac\u0103 vom trece switch-ul SW2 \u00een modul pvst cu comanda spanning-tree mode pvst, vom observa c\u0103 interfa\u021ba Fa0\/5 a trecut din nou \u00een starea Alternative, deoarece acum nu mai exist\u0103 diferentieri \u00eentre porturile de rezerv\u0103 \u0219i cele alternative. <\/p>\n

\"Antrenament
\n
\nA fost o lec\u021bie foarte lung\u0103 \u0219i dac\u0103 nu a\u021bi \u00een\u021beles ceva, v\u0103 sf\u0103tuiesc s\u0103 o revizui\u021bi \u00eenc\u0103 o dat\u0103. <\/p>\n

\r\n \"Reda\u021bi\r\n
<\/div>\r\n <\/div><\/center>
\nV\u0103 mul\u021bumim c\u0103 r\u0103m\u00e2ne\u021bi cu noi. V\u0103 plac articolele noastre? Dori\u021bi s\u0103 vede\u021bi mai multe materiale interesante? Sus\u021bine\u021bi-ne f\u0103c\u00e2nd o comand\u0103 sau recomand\u00e2ndu-ne prietenilor. 30% reducere pentru utilizatorii Habr pentru un server entry-level unic, creat special pentru tine:<\/b> Adev\u0103rul despre VPS (KVM) E5-2650 v4 (6 nuclee) 10GB DDR4 240GB SSD 1Gbps de la 20$ sau cum s\u0103 \u00eemp\u0103r\u021bim corect un server?<\/a><\/noindex> (sunt disponibile op\u021biuni cu RAID1 \u0219i RAID10, p\u00e2n\u0103 la 24 nuclee \u0219i p\u00e2n\u0103 la 40GB DDR4).<\/p>\n

Dell R730xd la jum\u0103tate de pre\u021b?<\/b> Numai la noi 2 x Intel TetraDeca-Core Xeon 2x E5-2697v3 2.6GHz 14C 64GB DDR4 4x960GB SSD 1Gbps 100 TB de la 199 $<\/a><\/noindex> \u00een Olanda! Dell R420 \u2014 2x E5-2430 2.2Ghz 6C 128GB DDR3 2x960GB SSD 1Gbps 100TB \u2014 de la 99 $!<\/b><\/b> Citi\u021bi despre Cum s\u0103 construi\u021bi o infrastructur\u0103 de clas\u0103 enterprise folosind servere Dell R730xd E5-2650 v4 la pre\u021buri foarte mici de 9000 \u20ac?<\/a><\/noindex>
\n
Sursa: habr.com<\/a><\/p>","protected":false,"gt_translate_keys":[{"key":"rendered","format":"html"}]},"excerpt":{"rendered":"

\u041f\u0440\u0435\u0434\u043f\u043e\u043b\u043e\u0436\u0438\u043c, \u0447\u0442\u043e STP \u043d\u0430\u0445\u043e\u0434\u0438\u0442\u0441\u044f \u0432 \u0441\u043e\u0441\u0442\u043e\u044f\u043d\u0438\u0438 \u0441\u0445\u043e\u0434\u0438\u043c\u043e\u0441\u0442\u0438. \u0427\u0442\u043e \u043f\u0440\u043e\u0438\u0437\u043e\u0439\u0434\u0435\u0442, \u0435\u0441\u043b\u0438 \u044f \u0432\u043e\u0437\u044c\u043c\u0443 \u043a\u0430\u0431\u0435\u043b\u044c \u0438 \u0441\u043e\u0435\u0434\u0438\u043d\u044e \u0441\u0432\u0438\u0442\u0447 \u041d \u043d\u0430\u043f\u0440\u044f\u043c\u0443\u044e \u0441 \u043a\u043e\u0440\u043d\u0435\u0432\u044b\u043c \u0441\u0432\u0438\u0442\u0447\u0435\u043c \u0410? Root Bridge \u00ab\u0443\u0432\u0438\u0434\u0438\u0442\u00bb, \u0447\u0442\u043e \u0443 \u043d\u0435\u0433\u043e \u043f\u043e\u044f\u0432\u0438\u043b\u0441\u044f \u043d\u043e\u0432\u044b\u0439 \u0437\u0430\u0434\u0435\u0439\u0441\u0442\u0432\u043e\u0432\u0430\u043d\u043d\u044b\u0439 \u043f\u043e\u0440\u0442, \u0438 \u043e\u0442\u043e\u0448\u043b\u0435\u0442 \u043f\u043e \u043d\u0435\u043c\u0443 BPDU. \u0421\u0432\u0438\u0442\u0447 \u041d, \u043f\u043e\u043b\u0443\u0447\u0438\u0432 \u044d\u0442\u043e\u0442 \u0444\u0440\u0435\u0439\u043c \u0441 \u043d\u0443\u043b\u0435\u0432\u043e\u0439 \u0441\u0442\u043e\u0438\u043c\u043e\u0441\u0442\u044c\u044e, \u043e\u043f\u0440\u0435\u0434\u0435\u043b\u0438\u0442 \u0441\u0442\u043e\u0438\u043c\u043e\u0441\u0442\u044c \u043c\u0430\u0440\u0448\u0440\u0443\u0442\u0430 \u0447\u0435\u0440\u0435\u0437 \u043d\u043e\u0432\u044b\u0439 \u043f\u043e\u0440\u0442 \u043a\u0430\u043a 0+19 =19 \u043f\u0440\u0438 […]<\/p>\n","protected":false,"gt_translate_keys":[{"key":"rendered","format":"html"}]},"author":1,"featured_media":28511,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[688],"tags":[],"class_list":["post-37988","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-administrirovanie"],"aioseo_notices":[],"aioseo_head":"\n\t\t\n\t\n\t\n\t\n\t\n\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\n","aioseo_head_json":{"title":"\ud83e\udd47Training Cisco 200-125 CCNA v3.0. 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