Namuhla sizobheka iphrothokholi ye-BGP. Ngeke sikhulume isikhathi eside ngokuthi kungani isetshenziswa futhi kungani isetshenziswa njengokuphela kwephrothokholi. Kunolwazi oluningi ngale ndaba, ngokwesibonelo .
Ngakho yini i-BGP? I-BGP iyiphrothokholi yomzila futhi iyona kuphela iphrothokholi ye-EGP (External Gateway Protocol). Le protocol isetshenziselwa ukwakha umzila ku-inthanethi. Ake sibheke ukuthi indawo yakhiwe kanjani phakathi kwamarutha amabili e-BGP.
Cabangela indawo ephakathi kwe-Router1 ne-Router3. Masizilungiselele sisebenzisa imiyalo elandelayo:
router bgp 10
network 192.168.12.0
network 192.168.13.0
neighbor 192.168.13.3 remote-as 10
router bgp 10
network 192.168.13.0
network 192.168.24.0
neighbor 192.168.13.1 remote-as 10Umakhelwane ongaphakathi kohlelo olulodwa oluzimele yi-AS 10. Ngemva kokufaka ulwazi kumzila, njenge-Router1, leyo router izama ukumisa ubuhlobo obuseduze ne-Router3. Isimo sokuqala lapho kungenzeki lutho kuthiwa Ingahle. Lapho nje i-bgp isilungiselelwe ku-Router1, izoqala ukulalela imbobo ye-TCP 179 - izongena kuhulumeni. Xhuma, futhi uma izama ukuvula iseshini nge-Router3, izongena kuhulumeni Active.
Ngemuva kokuthi iseshini isungulwe phakathi kwe-Router1 ne-Router3, imilayezo evuliwe iyashintshaniswa. Uma lo mlayezo uthunyelwa yi-Router1, lesi simo sizobizwa Vula Okuthunyelwe. Futhi uma ithola umlayezo ovuliwe ovela ku-Router3, izongena kuhulumeni Vula Qinisekisa. Ake sibhekisise umlayezo ovuliwe:
Lo mlayezo udlulisela ulwazi mayelana nephrothokholi ye-BGP ngokwayo, esetshenziswa umzila. Ngokushintshisana ngemilayezo evuliwe, i-Router1 ne-Router3 zixhumana ngolwazi mayelana nezilungiselelo zazo. Amapharamitha alandelayo adluliswa:
- Inguqulo: lokhu kuhlanganisa inguqulo ye-BGP esetshenziswa umzila. Inguqulo yamanje ye-BGP inguqulo 4 echazwe ku-RFC 4271. Amarutha amabili e-BGP azozama ukuxoxisana ngenguqulo ehambisanayo, lapho kukhona ukungafani khona-ke ngeke kube khona iseshini ye-BGP.
- I-AS yami: lokhu kuhlanganisa inombolo ye-AS yomzila we-BGP, amarutha kuyodingeka avumelane ngezinombolo ze-AS futhi kuchaza ukuthi azobe esebenzisa i-iBGP noma i-eBGP.
- Bamba Isikhathi: uma i-BGP ingatholi noma yimiphi imilayezo ephilayo noma ibuyekeze kusukela kolunye uhlangothi ngesikhathi sesikhathi sokubamba izosho ukuthi olunye uhlangothi 'lufile' futhi izodiliza iseshini ye-BGP. Ngokuzenzakalelayo isikhathi sokubamba sisethelwe kumasekhondi angu-180 kumarutha e-Cisco IOS, umlayezo wokugcina uthunyelwa njalo ngemizuzwana engama-60. Womabili amarutha kufanele avumelane ngesikhathi sokubamba noma ngeke kube khona iseshini ye-BGP.
- Isihlonzi se-BGP: lena i-ID yerutha ye-BGP yendawo ekhethwa njengoba kwenza i-OSPF:
- Sebenzisa i-ID yerutha eyalungiselelwa mathupha ngomyalo we-bgp router-id.
- Sebenzisa ikheli le-IP eliphezulu kakhulu kusixhumi esibonakalayo se-loopback.
- Sebenzisa ikheli le-IP eliphezulu kakhulu kusixhumi esibonakalayo esibonakalayo.
- Amapharamitha Okuzikhethela: lapha uzothola amakhono ongawakhetha werutha ye-BGP. Le nkambu yengezwe ukuze izici ezintsha zengezwe ku-BGP ngaphandle kokwenza inguqulo entsha.Izinto ongazithola lapha yilezi:
- ukwesekwa kwe-MP-BGP (Multi Protocol BGP).
- ukusekela Ukuvuselela Umzila.
- ukusekelwa kwezinombolo ze-AS ezingu-4-octet.
Ukuze kusungulwe indawo, lezi zimo ezilandelayo kufanele zihlangatshezwe:
- Inombolo yenguqulo. Inguqulo yamanje ingu-4.
- Inombolo ye-AS kufanele ifane nalokho okumisile umakhelwane 192.168.13.3 ukude-njengoba 10.
- I-ID yomzila kufanele ihluke kumakhelwane.
Uma noma yimaphi amapharamitha anganelisi lezi zimo, i-router izothumela Isaziso umlayezo okhombisa iphutha. Ngemva kokuthumela nokwamukela imilayezo evuliwe, ubudlelwano bomakhelwane bungena kuhulumeni Imisiwe. Ngemuva kwalokhu, ama-routers angashintshana ngolwazi mayelana nemizila futhi enze lokhu esebenzisa Update imiyalezo. Lona umlayezo Wokuvuselela othunyelwe ngu-Router1 ku-Router3:
Lapha ungabona amanethiwekhi abikwe izibaluli ze-Router1 kanye ne-Path, afana namamethrikhi. Sizokhuluma ngezimfanelo ze-Path ngokuningiliziwe. Imilayezo ye-Keepalive nayo ithunyelwa phakathi neseshini ye-TCP. Zidluliselwa, ngokuzenzakalelayo, njalo ngemizuzwana engama-60. Lesi Isibali sikhathi se-Keepalive. Uma umlayezo we-Keepalive ungatholwa ngesikhathi se-Hold Timer, lokhu kuzosho ukulahlekelwa ukuxhumana nomakhelwane. Ngokuzenzakalelayo, ilingana namasekhondi angu-180.
Uphawu oluwusizo:
Kubonakala sengathi sithole ukuthi ama-routers adlulisela kanjani ulwazi komunye nomunye, manje ake sizame ukuqonda umqondo we-protocol ye-BGP.
Ukukhangisa umzila etafuleni le-BGP, njengakuzivumelwano ze-IGP, kusetshenziswa umyalo wenethiwekhi, kodwa ingqondo yokusebenza ihlukile. Uma ku-IGP, ngemva kokucacisa umzila kumyalo wenethiwekhi, i-IGP ibheka ukuthi yiziphi izixhumi ezibonakalayo zale subnet futhi izifaka etafuleni layo, khona-ke umyalo wenethiwekhi ku-BGP ubheka itafula lomzila futhi ubheka ngqo ihambisana nomzila kumyalo wenethiwekhi. Uma ezinjalo zitholakala, le mizila izovela kuthebula le-BGP.
Bheka umzila kuthebula lomzila le-IP lamanje le-router efana ncamashi nemingcele yomyalo wenethiwekhi; uma umzila we-IP ukhona, faka i-NLRI efanayo kuthebula lendawo le-BGP.
Manje ake siphakamise i-BGP kubo bonke abasele futhi sibone ukuthi umzila ukhethwa kanjani phakathi kwe-AS eyodwa. Ngemva kokuba irutha ye-BGP ithola imizila kumakhelwane wayo, iqala ukukhetha umzila ofanele. Lapha udinga ukuqonda ukuthi yiluphi uhlobo lomakhelwane olungaba khona - lwangaphakathi nangaphandle. Ingabe umzila uyaqonda ngokumisa ukuthi umakhelwane omisiwe ungaphakathi noma ungaphandle? Uma eqenjini:
neighbor 192.168.13.3 remote-as 10 ipharamitha eyirimothi icacisa i-AS, ecushwa ku-router ngokwayo kumyalo we-router bgp 10. Imizila evela ku-AS yangaphakathi ibhekwa njengengaphakathi, futhi imizila evela ku-AS yangaphandle ibhekwa njengengaphandle. Futhi ngayinye, i-logic ehlukile yokwamukela nokuthumela imisebenzi. Cabangela le topology:
Irutha ngayinye inesixhumi esibonakalayo se-loopback esilungiselelwe nge-ip: xxxx 255.255.255.0 - lapho u-x kuyinombolo yomzila. Ku-Router9 sine-loopback interface enekheli - 9.9.9.9 255.255.255.0. Sizoyimemezela nge-BGP futhi sibone ukuthi isakazeka kanjani. Lo mzila uzodluliselwa ku-Router8 naku-Router12. Ukusuka ku-Router8, lo mzila uzoya ku-Router6, kodwa uye ku-Router5 ngeke ube kuthebula lomzila. Futhi ku-Router12 lo mzila uzovela kuthebula, kodwa naku-Router11 nawo ngeke ube khona. Ake sizame ukuthola lokhu. Ake sicabangele ukuthi iyiphi idatha namapharamitha i-Router9 edlulisela komakhelwane bayo, ibika lo mzila. Iphakethe elingezansi lizothunyelwa lisuka ku-Router9 liye ku-Router8.
Ulwazi lomzila luqukethe izibaluli ze-Path.
Izibaluli zendlela zihlukaniswe izigaba ezi-4:
- Impoqo eyaziwayo - Wonke amarutha asebenzisa i-BGP kufanele abone lezi zimfanelo. Kufanele ibe khona kuzo zonke izibuyekezo.
- I-discretionary eyaziwayo - Wonke amarutha asebenzisa i-BGP kufanele abone lezi zimfanelo. Bangase babe khona kuzibuyekezo, kodwa ubukhona babo abudingeki.
- Ukushintsha kokuzikhethela - angeke ibonwe yizo zonke izinhlelo zokusebenza ze-BGP. Uma i-router ingasiboni isibaluli, imaka isibuyekezo njengengxenye bese isidlulisela komakhelwane bayo, igcina isibaluli esingaziwa.
- Ongakukhetha akushintshi - angeke ibonwe yizo zonke izinhlelo zokusebenza ze-BGP. Uma i-router ingasiboni isibaluli, imfanelo ishaywa indiva futhi ilahlwe lapho idluliselwa komakhelwane.
Izibonelo zezibaluli ze-BGP:
- Impoqo eyaziwayo:
- Indlela yesistimu ezenzakalelayo
- Okulandelayo-hop
- Origin
- I-discretionary eyaziwayo:
- Okuthandwayo kwendawo
- I-atomic aggregate
- Ukushintsha kokuzikhethela:
- Isihlanganisi
- Imiphakathi
- Ongakukhetha akushintshi:
- I-Multi-exit discriminator (MED)
- I-ID yomqambi
- Uhlu lwamaqoqo
Kulokhu, okwamanje sizoba nentshisekelo ku-Origin, Next-hop, AS Path. Njengoba umzila udlula phakathi kwe-Router8 ne-Router9, okungukuthi, ngaphakathi kwe-AS eyodwa, kubhekwa njengokungaphakathi futhi sizonaka i-Origin.
Isibaluli somsuka - sibonisa ukuthi umzila osesibuyekezweni utholwe kanjani. Amanani ezibaluli ezingenzeka:
- 0 - IGP: I-NLRI itholwe ngaphakathi kohlelo lokuzimela lwangempela;
- 1 - EGP: I-NLRI ifundwa kusetshenziswa i-Exterior Gateway Protocol (EGP). Umanduleli ku-BGP, awusetshenziswa
- 2 - Akuphelele: I-NLRI yafundwa ngenye indlela
Esimweni sethu, njengoba kubonakala ephaketheni, lilingana no-0. Uma lo mzila udluliselwa ku-Router12, le khodi izoba nekhodi engu-1.
Okulandelayo, Next-hop. Isibaluli se-Next-hop
- Leli ikheli le-IP lerutha ye-eBGP lapho indlela eya kunethiwekhi yendawo ehamba ngayo.
- Isibaluli siyashintsha lapho isiqalo sithunyelwa kwenye i-AS.
Endabeni ye-iBGP, okungukuthi, ngaphakathi kwe-AS eyodwa, i-Next-hop izoboniswa yilowo ofundile noma otshelwe ngalo mzila. Esimweni sethu, kuzoba yi-192.168.89.9. Kodwa uma lo mzila udluliswa usuka ku-Router8 uye ku-Router6, i-Router8 izowushintsha bese ifaka owayo esikhundleni. I-Next-hop izoba ngu-192.168.68.8. Lokhu kusiholela emithethweni emibili:
- Uma irutha idlulisela phambili umzila kumakhelwane wayo wangaphakathi, ayishintshi ipharamitha ye-Next-hop.
- Uma i-router idlulisela umzila kumakhelwane wayo wangaphandle, ishintsha i-Next-hop iye ku-ip yesixhumi esibonakalayo lapho le router idlulisa khona.
Lokhu kusiholela ekuqondeni inkinga yokuqala - Kungani kungeke kube khona umzila kuthebula lomzila ku-Router5 naku-Router11. Ake sibhekisise. Ngakho-ke, i-Router6 ithole ulwazi mayelana nomzila 9.9.9.0/24 futhi yengeza ngempumelelo kuthebula lomzila:
Router6#show ip route bgp
Codes: L - local, C - connected, S - static, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2
i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
ia - IS-IS inter area, * - candidate default, U - per-user static route
o - ODR, P - periodic downloaded static route, H - NHRP, l - LISP
a - application route
+ - replicated route, % - next hop override, p - overrides from PfR
Gateway of last resort is not set
9.0.0.0/24 is subnetted, 1 subnets
B 9.9.9.0 [20/0] via 192.168.68.8, 00:38:25<source>
Теперь Router6 передал маршрут Router5 и первому правилу Next-hop не изменил. То есть, Router5 должен добавить <b>9.9.9.0 [20/0] via 192.168.68.8</b> , но у него нет маршрута до 192.168.68.8 и поэтому данный маршрут добавлен не будет, хотя информация о данном маршруте будет храниться в таблице BGP:
<source><b>Router5#show ip bgp
BGP table version is 1, local router ID is 5.5.5.5
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,
r RIB-failure, S Stale, m multipath, b backup-path, f RT-Filter,
x best-external, a additional-path, c RIB-compressed,
Origin codes: i - IGP, e - EGP, ? - incomplete
RPKI validation codes: V valid, I invalid, N Not found
Network Next Hop Metric LocPrf Weight Path
* i 9.9.9.0/24 192.168.68.8 0 100 0 45 i</b>Isimo esifanayo sizokwenzeka phakathi kwe-Router11-Router12. Ukuze ugweme lesi simo, udinga ukulungisa i-Router6 noma i-Router12, lapho udlula umzila oya komakhelwane babo bangaphakathi, ukuze ufake ikheli labo le-IP njenge-Next-hop. Lokhu kwenziwa kusetshenziswa umyalo:
neighbor 192.168.56.5 next-hop-selfNgemva kwalo myalo, i-Router6 izothumela umlayezo Wokubuyekeza, lapho i-ip yesixhumi esibonakalayo i-Gi0/0 Router6 izocaciswa njenge-Next-hop yemizila - 192.168.56.6, ngemva kwalokho lo mzila usuvele ufakiwe kuthebula lomzila.
Ake siye phambili futhi sibone ukuthi lo mzila uyavela yini ku-Router7 naku-Router10. Ngeke ibe etafuleni lomzila futhi singase sicabange ukuthi inkinga iyafana neyokuqala enepharamitha ye-Next-hop, kodwa uma sibheka umphumela womyalo we-ip bgp, sizobona ukuthi umzila awuzange wamukelwe lapho ngisho nange-Next-hop engalungile, okusho ukuthi umzila awuzange udluliselwe ngisho nokudluliswa. Futhi lokhu kuzosiholela ekubeni khona komunye umthetho:
Imizila etholwe komakhelwane bangaphakathi ayisakazwa kwabanye omakhelwane bangaphakathi.
Njengoba i-Router5 ithole umzila osuka ku-Router6, ngeke idluliselwe komunye umakhelwane wayo wangaphakathi. Ukuze ukudlulisa kwenzeke, udinga ukulungisa umsebenzi , noma ulungiselele ubudlelwano bomakhelwane obuxhumeke ngokugcwele (I-Mesh Egcwele), okungukuthi, i-Router5-7 wonke umuntu uzoba umakhelwane wawo wonke umuntu. Kulokhu sizosebenzisa i-Route Reflector. Ku-Router5 udinga ukusebenzisa lo myalo:
neighbor 192.168.57.7 route-reflector-clientI-Route-Reflector ishintsha ukuziphatha kwe-BGP lapho udlula umzila oya kumakhelwane wangaphakathi. Uma umakhelwane wangaphakathi echazwe ngokuthi umzila-reflector-iklayenti, bese imizila yangaphakathi izokhangiswa kulawa maklayenti.
Umzila awuvelanga ku-Router7? Ungakhohlwa nge-Next-hop futhi. Ngemuva kwalokhu kukhohlisa, umzila kufanele futhi uye ku-Router7, kodwa lokhu akwenzeki. Lokhu kusiletha komunye umthetho:
Umthetho we-next-hop usebenza kuphela emizileni yangaphandle. Emizileni yangaphakathi, isibaluli se-hop esilandelayo asishintshwa.
Futhi sithola isimo lapho kudingekile ukudala indawo kusetshenziswa umzila omile noma izivumelwano ze-IGP ukwazisa amarutha ngayo yonke imizila engaphakathi kwe-AS. Masibhalise imizila emile ku-Router6 naku-Router7 futhi ngemva kwalokho sizothola umzila esiwufunayo etafuleni lomzila. Ku-AS 678, sizokwenza ngokuhlukile kancane - sizobhalisa imizila emile ka-192.168.112.0/24 ku-Router10 kanye no-192.168.110.0/24 ku-Router12. Okulandelayo, sizosungula ubudlelwano bomakhelwane phakathi kwe-Router10 ne-Router12. Sizophinde silungiselele i-Router12 ukuthi ithumele i-hop yayo elandelayo ku-Router10:
neighbor 192.168.110.10 next-hop-selfUmphumela uzoba ukuthi i-Router10 izothola umzila 9.9.9.0/24, izotholwa kukho kokubili i-Router7 ne-Router12. Ake sibone ukuthi i-Router10 yenzani ukukhetha:
Router10#show ip bgp
BGP table version is 3, local router ID is 6.6.6.6
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,
r RIB-failure, S Stale, m multipath, b backup-path, f RT-Filter,
x best-external, a additional-path, c RIB-compressed,
Origin codes: i - IGP, e - EGP, ? - incomplete
RPKI validation codes: V valid, I invalid, N Not found
Network Next Hop Metric LocPrf Weight Path
*>i 9.9.9.0/24 192.168.112.12 0 100 0 45 i
192.168.107.7 0 123 45 i
Njengoba singabona, imizila emibili nomcibisholo (>) kusho ukuthi umzila odlula 192.168.112.12 ukhethiwe.
Ake sibone ukuthi inqubo yokukhetha umzila isebenza kanjani:
- Isinyathelo sokuqala lapho uthola umzila ukuhlola ukutholakala kwe-Next-hop yayo. Kungakho, lapho sithola umzila ku-Router5 ngaphandle kokusetha i-Next-hop-self, lo mzila awuzange uqhubeke ucutshungulwa.
- Okulandelayo kuza ipharamitha Yesisindo. Le pharamitha ayisona Isibaluli Sendlela (PA) futhi ayithunyelwa kumilayezo ye-BGP. Ilungiselelwe endaweni kumzila ngamunye futhi isetshenziselwa ukuphatha ukukhetha komzila kumzila ngokwawo. Ake sibheke isibonelo. Ngenhla nje ungabona ukuthi i-Router10 ikhethe umzila we-9.9.9.0/24 nge-Router12 (192.168.112.12). Ukuze ushintshe ipharamitha ye-Wieght, ungasebenzisa imephu yomzila ukuze usethe imizila ethile, noma unikeze isisindo kumakhelwane wakho usebenzisa umyalo:
neighbor 192.168.107.7 weight 200Manje yonke imizila evela kulo makhelwane izoba nalesi sisindo. Ake sibone ukuthi ukukhetha komzila kushintsha kanjani ngemva kwalokhu kukhohlisa:
Router10#show bgp *Mar 2 11:58:13.956: %SYS-5-CONFIG_I: Configured from console by console BGP table version is 2, local router ID is 6.6.6.6 Status codes: s suppressed, d damped, h history, * valid, > best, i - internal, r RIB-failure, S Stale, m multipath, b backup-path, f RT-Filter, x best-external, a additional-path, c RIB-compressed, Origin codes: i - IGP, e - EGP, ? - incomplete RPKI validation codes: V valid, I invalid, N Not found Network Next Hop Metric LocPrf Weight Path *> 9.9.9.0/24 192.168.107.7 200 123 45 i * i 192.168.112.12 0 100 0 45 iNjengoba ubona, umzila odlula ku-Router7 usukhethiwe, kodwa lokhu ngeke kube nomthelela kwamanye amarutha.
- Esikhaleni sesithathu sinokukhethwa Kwasendaweni. Le parameter iyisibaluli Esaziwa kakhulu sokukhetha, okusho ukuthi ukuba khona kwayo kungokuzithandela. Le parameter isebenza kuphela ngaphakathi kwe-AS eyodwa futhi ithinta ukukhetha kwendlela komakhelwane bangaphakathi kuphela. Yingakho idluliselwa kuphela kumilayezo yoBuyekeza ehloselwe umakhelwane wangaphakathi. Alikho ku-Buyekeza imilayezo komakhelwane bangaphandle. Ngakho-ke, yahlukaniswa njenge-Discretionary eyaziwayo. Ake sizame ukusisebenzisa ku-Router5. Ku-Router5 kufanele sibe nemizila emibili ye-9.9.9.0/24 - owodwa udlule ku-Router6 nowesibili udlule ku-Router7.
Sibheka:
Router5#show bgp BGP table version is 2, local router ID is 5.5.5.5 Status codes: s suppressed, d damped, h history, * valid, > best, i - internal, r RIB-failure, S Stale, m multipath, b backup-path, f RT-Filter, x best-external, a additional-path, c RIB-compressed, Origin codes: i - IGP, e - EGP, ? - incomplete RPKI validation codes: V valid, I invalid, N Not found Network Next Hop Metric LocPrf Weight Path *>i 9.9.9.0/24 192.168.56.6 0 100 0 45 iKodwa njengoba sibona umzila owodwa ngokusebenzisa i-Router6. Uphi umzila odlula ku-Router7? Mhlawumbe i-Router7 nayo ayinayo? Ake sibheke:
Router#show bgp BGP table version is 10, local router ID is 7.7.7.7 Status codes: s suppressed, d damped, h history, * valid, > best, i - internal, r RIB-failure, S Stale, m multipath, b backup-path, f RT-Filter, x best-external, a additional-path, c RIB-compressed, Origin codes: i - IGP, e - EGP, ? - incomplete RPKI validation codes: V valid, I invalid, N Not found Network Next Hop Metric LocPrf Weight Path *>i 9.9.9.0/24 192.168.56.6 0 100 0 45 i 192.168.107.10 0 678 45 iKuyamangaza, konke kubonakala kuhamba kahle. Kungani ingadluliswanga ku-Router5? Into ukuthi i-BGP inomthetho:
I-router idlulisa kuphela leyo mizila eyisebenzisayo.
I-Router7 isebenzisa umzila odlula ku-Router5, ngakho umzila odlula ku-Router10 ngeke usakazwe. Masibuyele Kokuncamelayo Kwasendaweni. Masisethe Okuthandwayo Kwasendaweni ku-Router7 futhi sibone ukuthi i-Router5 isabela kanjani kulokhu:
route-map BGP permit 10 match ip address 10 set local-preference 250 access-list 10 permit any router bgp 123 neighbor 192.168.107.10 route-map BGP in</b>Ngakho-ke, sidale imephu yomzila equkethe yonke imizila futhi satshela i-Router7 ukuthi iguqule ipharamitha ye-Local Preference ibe ngu-250 uma yamukelwe, okuzenzakalelayo ngu-100. Ake sibone ukuthi kwenzekeni ku-Router5:
Router5#show bgp BGP table version is 8, local router ID is 5.5.5.5 Status codes: s suppressed, d damped, h history, * valid, > best, i - internal, r RIB-failure, S Stale, m multipath, b backup-path, f RT-Filter, x best-external, a additional-path, c RIB-compressed, Origin codes: i - IGP, e - EGP, ? - incomplete RPKI validation codes: V valid, I invalid, N Not found Network Next Hop Metric LocPrf Weight Path *>i 9.9.9.0/24 192.168.57.7 0 250 0 678 45 iNjengoba sibona manje i-Router5 ikhetha umzila odlula ku-Router7. Isithombe esifanayo sizoba ku-Router6, nakuba kunenzuzo enkulu kuye ukukhetha umzila odlula ku-Router8. Futhi sengeza ukuthi ukushintsha le pharamitha kudinga ukuqaliswa kabusha kwendawo ukuze ushintsho lusebenze. Funda . Silungise Okuncamelayo Kwasendaweni. Asiqhubekele kupharamitha elandelayo.
- Uncamela umzila onepharamitha ye-Next-hop engu-0.0.0.0, okungukuthi, imizila yendawo noma ehlanganisiwe. Le mizila inikezwa ngokuzenzakalelayo ipharamitha Yesisindo elingana nobukhulu—32678—ngemuva kokufaka umyalo wenethiwekhi:
Router#show bgp BGP table version is 2, local router ID is 9.9.9.9 Status codes: s suppressed, d damped, h history, * valid, > best, i - internal, r RIB-failure, S Stale, m multipath, b backup-path, f RT-Filter, x best-external, a additional-path, c RIB-compressed, Origin codes: i - IGP, e - EGP, ? - incomplete RPKI validation codes: V valid, I invalid, N Not found Network Next Hop Metric LocPrf Weight Path *> 9.9.9.0/24 0.0.0.0 0 32768 i - Indlela emfushane nge-AS. Ipharamitha ye-AS_Path emfushane kakhulu ikhethiwe. Uma umzila udlula ama-AS ambalwa, kuba ngcono. Cabangela umzila oya ku-9.9.9.0/24 ku-Router10:
Router10#show bgp BGP table version is 2, local router ID is 6.6.6.6 Status codes: s suppressed, d damped, h history, * valid, > best, i - internal, r RIB-failure, S Stale, m multipath, b backup-path, f RT-Filter, x best-external, a additional-path, c RIB-compressed, Origin codes: i - IGP, e - EGP, ? - incomplete RPKI validation codes: V valid, I invalid, N Not found Network Next Hop Metric LocPrf Weight Path * 9.9.9.0/24 192.168.107.7 0 123 45 i *>i 192.168.112.12 0 100 0 45 iNjengoba ubona, i-Router10 ikhethe umzila nge-192.168.112.12 ngoba kulo mzila ipharamitha ye-AS_Path iqukethe kuphela ama-45, futhi kwesinye isimo 123 kanye no-45. I-Intuitively clear.
- Ipharamitha elandelayo ithi Origin. I-IGP (umzila otholwe kusetshenziswa i-BGP) ungcono kune-EGP (umzila otholwe kusetshenziswa owandulelayo we-BGP, awusasebenzi), futhi i-EGP ingcono kunokungaphelele? (kutholwe enye indlela, isibonelo ngokusabalalisa kabusha).
- Ipharamitha elandelayo i-MED. Sine-Wieght esebenza endaweni kuphela kumzila. Kwakukhona i-Local Preference, eyayisebenza kuphela ohlelweni olulodwa oluzimele. Njengoba ungase uqagele, i-MED iyipharamitha ezodluliselwa phakathi kwezinhlelo ezizimele. Kuhle kakhulu mayelana nale pharamitha.
Azisekho izibaluli ezizosetshenziswa, kodwa uma imizila emibili inezimfanelo ezifanayo, kusetshenziswa imithetho elandelayo:
- Khetha indlela eya kumakhelwane we-IGP oseduze.
- Khetha umzila omdala kakhulu wendlela ye-eBGP.
- Khetha indlela eya kumakhelwane ene-ID yomzila we-BGP encane kakhulu.
- Khetha indlela eya kumakhelwane enekheli le-IP eliphansi kakhulu.
Manje ake sibheke udaba lokuhlangana kwe-BGP.
Ake sibone ukuthi yini eyenzekayo uma i-Router6 ilahlekelwa umzila 9.9.9.0/24 ngokusebenzisa i-Router9. Ake sikhubaze isixhumi esibonakalayo i-Gi0/1 ye-Router6, ezoqonda ngokushesha ukuthi iseshini ye-BGP ene-Router8 inqanyuliwe futhi umakhelwane unyamalele, okusho ukuthi umzila owamukelwe kuwo awusebenzi. I-Router6 ithumela ngokushesha imilayezo yoBuyekeza, lapho ikhombisa khona inethiwekhi 9.9.9.0/24 kunkambu yeMizila Ehoxisiwe. Uma nje i-Router5 ithola umlayezo onjalo, izowuthumela ku-Router7. Kodwa njengoba i-Router7 inomzila odlula ku-Router10, izophendula ngokushesha nge-Update ngomzila omusha. Uma kungenakwenzeka ukuthola ukuwa komakhelwane ngokusekelwe esimweni se-interface, kuzodingeka ulinde ukuthi I-Bamba Isikhathi siqhume.
Inhlangano.
Uma ukhumbula, sikhulume ngeqiniso lokuthi ngokuvamile kufanele usebenzise i-topology exhunywe ngokugcwele. Ngenani elikhulu lama-routers kwelinye AS lokhu kungabangela izinkinga ezinkulu, ukugwema lokhu udinga ukusebenzisa izinhlangano. I-AS eyodwa ihlukaniswe ngama-sub-AS ambalwa, okubavumela ukuthi basebenze ngaphandle kwemfuneko ye-topology exhunywe ngokugcwele.
Nasi isixhumanisi salokhu , futhi ukucushwa kwe-GNS3.
Isibonelo, ngale topology kuzodingeka sixhumanise wonke amarutha ku-AS 2345 komunye nomunye, kodwa sisebenzisa i-Confederation, singakwazi ukusungula ubudlelwano obuseduze phakathi kwamarutha axhumene ngokuqondile. Ake sixoxe kabanzi ngalokhu. Ukube besine-AS 2345 kuphela, ke laForge ngithole imashi evela Picard uzoyitshela ama-routers Idatha и I-Worf, kodwa abakwazanga ukutshela umzila ngakho I-Crusher . Futhi imizila esatshalaliswa irutha ngokwayo laForge, bekungeke kudluliswe I-Crusher noma I-Worf-o, cha Idatha.
Kuzodingeka ulungiselele i-Route-Reflector noma ubudlelwano bomakhelwane obuxhumeke ngokugcwele. Ngokuhlukanisa i-AS 2345 eyodwa ibe yi-4 sub-AS (2,3,4,5) kumzila ngamunye, sigcina sinomqondo ohlukile wokusebenza. Konke kuchazwe ngokuphelele .
Imithombo:
- I-CCIE Routing and Switching v5.0 Official Cert Guide, Volume 2, Fifth Edition, Narbik Kocharians, Terry Vinson.
- iwebhusayithi
- iwebhusayithi .
Source: www.habr.com