Loni a yoo wo ilana BGP. A kii yoo sọrọ fun igba pipẹ nipa idi ti o fi jẹ ati idi ti o fi lo bi ilana nikan. Alaye pupọ wa lori koko yii, fun apẹẹrẹ .
Nitorina kini BGP? BGP jẹ ilana ipa ọna ti o ni agbara ati pe o jẹ ilana EGP (Ilana Ẹnu-ọna Ita) nikan. Ilana yii jẹ lilo lati kọ ipa-ọna lori Intanẹẹti. Jẹ ki a wo bi a ṣe kọ agbegbe kan laarin awọn onimọ-ọna BGP meji.
Ro agbegbe laarin Router1 ati Router3. Jẹ ki a tunto wọn nipa lilo awọn aṣẹ wọnyi:
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 10Adugbo laarin eto adase kan jẹ AS 10. Lẹhin titẹ alaye sii lori olulana, gẹgẹbi Router1, olulana naa ngbiyanju lati ṣeto ibatan isunmọ pẹlu Router3. Ipo ibẹrẹ nigbati ohunkohun ko ṣẹlẹ ni a pe laišišẹ. Ni kete ti bgp ti tunto lori Router1, yoo bẹrẹ gbigbọ TCP ibudo 179 - yoo lọ si ipinlẹ naa. So, ati nigbati o ba gbiyanju lati ṣii igba kan pẹlu Router3, yoo lọ sinu ipinle ti nṣiṣe lọwọ.
Lẹhin igba ti iṣeto laarin Router1 ati Router3, Ṣii awọn ifiranṣẹ ti wa ni paarọ. Nigbati yi ifiranṣẹ ti wa ni rán nipa Router1, yi ipinle yoo wa ni a npe ni Ṣii Ti firanṣẹ. Ati nigbati o ba gba ifiranṣẹ Ṣii lati ọdọ Router3, yoo lọ sinu ipinle naa Ṣii Jẹrisi. Jẹ ki a ṣe akiyesi diẹ si ifiranṣẹ Ṣii:
Ifiranṣẹ yii ṣe alaye nipa ilana BGP funrararẹ, eyiti olulana nlo. Nipa paṣipaarọ Ṣii awọn ifiranṣẹ, Router1 ati Router3 ibasọrọ alaye nipa eto wọn si kọọkan miiran. Awọn paramita wọnyi ti kọja:
- version: eyi pẹlu ẹya BGP ti olulana nlo. Ẹya ti isiyi ti BGP jẹ ẹya 4 eyiti o ṣe apejuwe ni RFC 4271. Awọn onimọ-ọna BGP meji yoo gbiyanju lati dunadura ẹya ibaramu, nigbati ibaamu kan ba wa lẹhinna ko si igba BGP.
- AS mi: eyi pẹlu nọmba AS ti olulana BGP, awọn olulana yoo ni lati gba lori nọmba AS ati pe o tun ṣalaye boya wọn yoo ṣiṣẹ iBGP tabi eBGP.
- Mu Aago: ti BGP ko ba gba itọju laaye tabi imudojuiwọn awọn ifiranṣẹ lati apa keji fun iye akoko akoko idaduro lẹhinna yoo kede ẹgbẹ keji 'okú' ati pe yoo wó igba BGP naa. Nipa aiyipada akoko idaduro ti ṣeto si awọn aaya 180 lori awọn onimọ-ọna Sisiko IOS, ifiranšẹ keepalive ti wa ni rán gbogbo 60 aaya. Awọn olulana mejeeji ni lati gba lori akoko idaduro tabi kii yoo jẹ igba BGP kan.
- BGP Idanimọ: Eyi ni ID olulana BGP agbegbe ti o yan gẹgẹbi OSPF ṣe:
- Lo ID olulana ti a tunto pẹlu ọwọ pẹlu aṣẹ bgp router-id.
- Lo adiresi IP ti o ga julọ lori wiwo loopback.
- Lo adiresi IP ti o ga julọ lori wiwo ti ara.
- Iyan paramita: Nibi iwọ yoo rii diẹ ninu awọn agbara aṣayan ti olulana BGP. A ti ṣafikun aaye yii ki awọn ẹya tuntun le ṣafikun si BGP laisi nini lati ṣẹda ẹya tuntun. Awọn nkan ti o le rii nibi ni:
- atilẹyin fun MP-BGP (Multi Protocol BGP).
- support fun Route Sọ.
- atilẹyin fun 4-octet AS awọn nọmba.
Lati ṣeto agbegbe kan, awọn ipo wọnyi gbọdọ pade:
- Nọmba ẹya. Ẹya lọwọlọwọ jẹ 4.
- Nọmba AS gbọdọ baramu ohun ti o ti tunto aládùúgbò 192.168.13.3 latọna jijin-bi 10.
- ID olulana gbọdọ yatọ si aladugbo.
Ti eyikeyi ninu awọn paramita ko ni itẹlọrun awọn ipo wọnyi, olulana yoo firanṣẹ iwifunni ifiranṣẹ ti o tọkasi aṣiṣe. Lẹhin fifiranṣẹ ati gbigba awọn ifiranṣẹ Ṣii silẹ, ibatan agbegbe wọ inu ipinlẹ naa AṢẸṢẸ. Lẹhin eyi, awọn olulana le ṣe paṣipaarọ alaye nipa awọn ipa-ọna ati ṣe eyi nipa lilo Update awọn ifiranṣẹ. Eyi ni ifiranṣẹ imudojuiwọn ti a firanṣẹ nipasẹ Router1 si Router3:
Nibi o le rii awọn nẹtiwọọki ti o royin nipasẹ Router1 ati awọn abuda ọna, eyiti o jẹ afọwọṣe si awọn metiriki. A yoo sọrọ nipa awọn abuda Ọna ni awọn alaye diẹ sii. Awọn ifiranšẹ Keepalive tun wa laarin igba TCP kan. Wọn ti tan kaakiri, nipasẹ aiyipada, ni gbogbo 60 iṣẹju-aaya. Eleyi jẹ a Keepalive Aago. Ti ifiranṣẹ Keepalive ko ba gba lakoko Aago Idaduro, eyi yoo tumọ si ipadanu ibaraẹnisọrọ pẹlu aladugbo. Nipa aiyipada, o jẹ dogba si awọn aaya 180.
Ami iwulo:
O dabi pe a ti ṣawari bi awọn onimọ-ọna ṣe ntan alaye si ara wọn, ni bayi jẹ ki a gbiyanju lati ni oye imọran ti ilana BGP.
Lati polowo ipa-ọna si tabili BGP, gẹgẹbi ninu awọn ilana IGP, a lo pipaṣẹ nẹtiwọki, ṣugbọn ọgbọn-iṣiṣẹ yatọ. Ti o ba wa ni IGP, lẹhin asọye ipa-ọna ninu pipaṣẹ nẹtiwọọki, IGP wo iru awọn atọkun ti o jẹ ti subnet yii ati pẹlu wọn ninu tabili rẹ, lẹhinna aṣẹ nẹtiwọọki ni BGP wo tabili lilọ kiri ati wa fun kongẹ ibaamu ipa ọna ninu pipaṣẹ nẹtiwọki. Ti o ba rii iru bẹ, awọn ipa-ọna wọnyi yoo han ninu tabili BGP.
Wa ipa-ọna ninu tabili olulana IP lọwọlọwọ ti olulana ti o baamu deede awọn aye ti pipaṣẹ nẹtiwọọki; ti ipa ọna IP ba wa, fi NLRI deede sinu tabili BGP agbegbe.
Bayi jẹ ki a gbe BGP soke si gbogbo awọn ti o ku ki o wo bi a ṣe yan ipa ọna laarin AS kan. Lẹhin ti olulana BGP gba awọn ipa-ọna lati ọdọ aladugbo rẹ, o bẹrẹ yiyan ipa-ọna to dara julọ. Nibi o nilo lati ni oye kini iru awọn aladugbo le jẹ - inu ati ita. Ṣe olulana ni oye nipasẹ iṣeto ni boya aladugbo tunto jẹ inu tabi ita? Ti o ba wa ni ẹgbẹ kan:
neighbor 192.168.13.3 remote-as 10 awọn latọna jijin-bi paramita pato AS, eyi ti o wa ni tunto lori awọn olulana ara ninu awọn olulana bgp 10 pipaṣẹ. Ati fun ọkọọkan, ọgbọn oriṣiriṣi ti gbigba ati fifiranṣẹ awọn iṣẹ. Wo topology yii:
Olulana kọọkan ni wiwo loopback tunto pẹlu ip: x.x.x.x 255.255.255.0 - nibiti x wa nọmba olulana. Lori Router9 a ni wiwo loopback pẹlu adirẹsi - 9.9.9.9 255.255.255.0. A yoo kede rẹ nipasẹ BGP ati ki o wo bi o ti n tan. Ọna yii yoo gbe lọ si Router8 ati Router12. Lati Router8, ipa ọna yii yoo lọ si Router6, ṣugbọn si Router5 kii yoo wa ni tabili afisona. Paapaa lori Router12 ọna yii yoo han ninu tabili, ṣugbọn lori Router11 kii yoo wa nibẹ boya. Jẹ ká gbiyanju lati ro ero yi jade. Jẹ ki ká ro ohun ti data ati awọn paramita Router9 ndari si awọn oniwe-aladugbo, riroyin yi ipa ọna. Awọn apo-iwe ti o wa ni isalẹ yoo firanṣẹ lati Router9 si Router8.
Alaye ipa ọna ni awọn ẹya ara ipa ọna.
Awọn abuda ọna ti pin si awọn ẹka mẹrin:
- Daradara-mọ dandan - Gbogbo awọn olulana ti nṣiṣẹ BGP gbọdọ da awọn abuda wọnyi mọ. Gbọdọ wa ni gbogbo awọn imudojuiwọn.
- Daradara-mọ lakaye - Gbogbo awọn olulana ti nṣiṣẹ BGP gbọdọ da awọn abuda wọnyi mọ. Wọn le wa ni awọn imudojuiwọn, ṣugbọn wiwa wọn ko nilo.
- Irekọja iyan - le ma ṣe idanimọ nipasẹ gbogbo awọn imuse BGP. Ti olulana ko ba da abuda naa mọ, o samisi imudojuiwọn bi apa kan ati firanṣẹ siwaju si awọn aladugbo rẹ, titoju abuda ti a ko mọ.
- Iyan ti kii-transitive - le ma ṣe idanimọ nipasẹ gbogbo awọn imuse BGP. Ti olulana naa ko ba da abuda naa mọ, lẹhinna abuda naa jẹ aibikita ati asonu nigbati o kọja si awọn aladugbo.
Awọn apẹẹrẹ ti awọn abuda BGP:
- Daradara-mọ dandan:
- Ona eto adase
- Next-hop
- Oti
- Daradara-mọ lakaye:
- Iyanfẹ agbegbe
- Atomic apapọ
- Irekọja iyan:
- Alakojo
- Awọn agbegbe
- Iyan ti kii-transitive:
- Iyatọ-jade lọpọlọpọ (MED)
- ID olupilẹṣẹ
- Akojọ akojọpọ
Ni idi eyi, fun bayi a yoo nifẹ si Oti, Next-hop, AS Path. Niwọn igba ti ipa ọna naa n gbejade laarin Router8 ati Router9, iyẹn ni, laarin AS kan, a ka inu inu ati pe a yoo san ifojusi si Oti.
Ẹya ipilẹṣẹ - tọkasi bii ipa-ọna ninu imudojuiwọn ṣe gba. Awọn iye abuda to ṣeeṣe:
- 0 - IGP: NLRI gba laarin awọn atilẹba adase eto;
- 1 - EGP: NLRI ti kọ ẹkọ nipa lilo Ilana Ẹnu Ode (EGP). Aṣaaju si BGP, ko lo
- 2 - Ti ko pari: NLRI ti kọ ẹkọ ni ọna miiran
Ninu ọran wa, bi a ti le rii lati apo-iwe, o jẹ dogba si 0. Nigbati ipa ọna yii ba tan si Router12, koodu yii yoo ni koodu ti 1.
Nigbamii, Next-hop. Next-hop abuda
- Eyi ni adiresi IP ti olulana eBGP nipasẹ eyiti ọna si nẹtiwọki ti nlo.
- Ẹya naa yipada nigbati ami-iṣaaju ti firanṣẹ si AS miiran.
Ninu ọran iBGP, iyẹn, laarin AS kan, Next-hop yoo jẹ itọkasi nipasẹ ẹni ti o kọ tabi sọ nipa ipa ọna yii. Ninu ọran wa, yoo jẹ 192.168.89.9. Ṣugbọn nigbati ọna yii ba ti gbejade lati Router8 si Router6, Router8 yoo yi pada ki o rọpo rẹ pẹlu tirẹ. Next-hop yoo jẹ 192.168.68.8. Eyi nyorisi wa si awọn ofin meji:
- Ti o ba ti a olulana dari a ipa si awọn oniwe-ti abẹnu aládùúgbò, o ko ni yi Next-hop paramita.
- Ti o ba ti a olulana ndari a ipa si awọn oniwe-ita aládùúgbò, o ayipada Next-hop si awọn ip ti awọn wiwo lati eyi ti yi olulana ndari.
Eyi nyorisi wa lati ni oye iṣoro akọkọ - Kini idi ti ko si ipa-ọna ninu tabili ipa-ọna lori Router5 ati Router11. Jẹ ki a ṣe akiyesi diẹ sii. Nitorinaa, Router6 gba alaye nipa ipa-ọna 9.9.9.0/24 ati ni ifijišẹ ṣafikun si tabili ipa-ọna:
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>Ipo kanna yoo ṣẹlẹ laarin Router11-Router12. Lati yago fun ipo yii, o nilo lati tunto Router6 tabi Router12, nigbati o ba kọja ọna si awọn aladugbo inu wọn, lati paarọ adiresi IP wọn bi Next-hop. Eyi ni a ṣe nipa lilo aṣẹ:
neighbor 192.168.56.5 next-hop-selfLẹhin aṣẹ yii, Router6 yoo fi ifiranṣẹ imudojuiwọn kan ranṣẹ, nibiti ip ti wiwo Gi0/0 Router6 yoo jẹ pato bi Next-hop fun awọn ipa-ọna - 192.168.56.6, lẹhin eyi ipa-ọna yii yoo wa tẹlẹ ninu tabili itọnisọna.
Jẹ ki a lọ siwaju ki o rii boya ipa ọna yii ba han lori Router7 ati Router10. Kii yoo wa ninu tabili afisona ati pe a le ro pe iṣoro naa jẹ kanna bii ti akọkọ pẹlu paramita Next-hop, ṣugbọn ti a ba wo abajade ti aṣẹ ip bgp show, a yoo rii pe a ko gba ipa-ọna nibẹ paapaa pẹlu Next-hop ti ko tọ, eyi ti o tumọ si pe a ko ti gbe ọna naa paapaa. Ati pe eyi yoo mu wa lọ si aye ti ofin miiran:
Awọn ipa ọna ti a gba lati ọdọ awọn aladugbo inu ko ni ikede si awọn aladugbo inu miiran.
Niwọn igba ti Router5 ti gba ọna lati ọdọ Router6, kii yoo tan kaakiri si aladugbo inu miiran miiran. Ni ibere fun gbigbe lati waye, o nilo lati tunto iṣẹ naa , tabi tunto awọn ibatan agbegbe ti o ni asopọ ni kikun (Full Mesh), iyẹn ni, Router5-7 gbogbo eniyan yoo jẹ aladugbo si gbogbo eniyan. Ni idi eyi a yoo lo Route Reflector. Lori Router5 o nilo lati lo aṣẹ yii:
neighbor 192.168.57.7 route-reflector-clientIpa ọna-Reflector yi ihuwasi BGP pada nigbati o ba nkọja ipa ọna si aladugbo inu. Ti o ba ti abẹnu aládùúgbò wa ni pato bi ipa-reflector-onibara, lẹhinna awọn ipa-ọna inu yoo wa ni ipolowo si awọn onibara wọnyi.
Ọna naa ko han loju Router7? Maṣe gbagbe nipa Next-hop boya. Lẹhin awọn ifọwọyi wọnyi, ọna yẹ ki o tun lọ si Router7, ṣugbọn eyi ko ṣẹlẹ. Eyi mu wa wá si ofin miiran:
Ofin hop atẹle n ṣiṣẹ fun awọn ipa-ọna Ita nikan. Fun awọn ipa-ọna inu, abuda-hop atẹle ko rọpo.
Ati pe a gba ipo kan ninu eyiti o jẹ dandan lati ṣẹda agbegbe nipa lilo ipa-ọna aimi tabi awọn ilana IGP lati sọ fun awọn olulana nipa gbogbo awọn ipa-ọna laarin AS. Jẹ ki a forukọsilẹ awọn ipa ọna aimi lori Router6 ati Router7 ati lẹhin iyẹn a yoo gba ọna ti o fẹ ni tabili olulana. Ni AS 678, a yoo ṣe ni iyatọ diẹ - a yoo forukọsilẹ awọn ipa ọna aimi fun 192.168.112.0/24 lori Router10 ati 192.168.110.0/24 lori Router12. Nigbamii ti, a yoo fi idi ibatan agbegbe laarin Router10 ati Router12. A yoo tun tunto Router12 lati firanṣẹ atẹle-hop rẹ si Router10:
neighbor 192.168.110.10 next-hop-selfAbajade yoo jẹ pe Router10 yoo gba ipa ọna 9.9.9.0/24, yoo gba lati ọdọ Router7 ati Router12 mejeeji. Jẹ ki a wo kini yiyan Router10 ṣe:
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
Bi a ti le ri, awọn ọna meji ati itọka (>) tumọ si pe ọna nipasẹ 192.168.112.12 ti yan.
Jẹ ki a wo bii ilana yiyan ipa-ọna ṣe n ṣiṣẹ:
- Igbesẹ akọkọ nigba gbigba ipa ọna ni lati ṣayẹwo wiwa ti Next-hop rẹ. Ti o ni idi, nigba ti a ba gba ipa ọna lori Router5 lai ṣeto Next-hop-self, yi ipa ọna ti a ko siwaju sii ni ilọsiwaju.
- Nigbamii ti o wa ni iwuwo paramita. Paramita yii kii ṣe Ẹya Ọna (PA) ati pe ko firanṣẹ ni awọn ifiranṣẹ BGP. O ti tunto ni agbegbe lori olulana kọọkan ati pe o lo nikan lati ṣe afọwọyi yiyan ipa-ọna lori olulana funrararẹ. Jẹ́ ká wo àpẹẹrẹ kan. O kan loke o le rii pe Router10 ti yan ipa-ọna fun 9.9.9.0/24 nipasẹ Router12 (192.168.112.12). Lati yi paramita Wieight pada, o le lo maapu ipa-ọna lati ṣeto awọn ipa-ọna kan pato, tabi fi iwuwo kan si aladugbo rẹ nipa lilo aṣẹ:
neighbor 192.168.107.7 weight 200Bayi gbogbo awọn ipa-ọna lati ọdọ aladugbo yii yoo ni iwuwo yii. Jẹ ki a wo bii yiyan ipa-ọna ṣe yipada lẹhin ifọwọyi yii:
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 iBii o ti le rii, ọna nipasẹ Router7 ti yan ni bayi, ṣugbọn eyi kii yoo ni ipa eyikeyi lori awọn olulana miiran.
- Ni ipo kẹta a ni Iyanfẹ Agbegbe. Paramita yii jẹ abuda lakaye ti a mọ daradara, eyiti o tumọ si pe wiwa rẹ jẹ iyan. Paramita yii wulo laarin AS kan nikan ati pe yoo ni ipa lori yiyan ọna nikan fun awọn aladugbo inu. Ti o ni idi ti o ti gbejade nikan ni Awọn ifiranṣẹ imudojuiwọn ti a pinnu fun aladugbo inu. Ko si ninu awọn ifiranṣẹ imudojuiwọn fun awọn aladugbo ita. Nitorinaa, o ti pin si bi lakaye ti a mọ daradara. Jẹ ki a gbiyanju lati lo lori Router5. Lori Router5 a yẹ ki o ni awọn ọna meji fun 9.9.9.0/24 - ọkan nipasẹ Router6 ati keji nipasẹ Router7.
A wo:
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 iṢugbọn bi a ti rii ọna kan nipasẹ Router6. Nibo ni ipa ọna nipasẹ Router7? Boya Router7 ko ni boya? Jẹ ki a wo:
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 iIyalẹnu, ohun gbogbo dabi pe o dara. Kilode ti a ko gbejade si Router5? Ohun naa ni pe BGP ni ofin kan:
Awọn olulana ndari nikan awon ipa-ti o nlo.
Router7 nlo ipa ọna nipasẹ Router5, nitorinaa ọna nipasẹ Router10 kii yoo tan kaakiri. Jẹ ki a pada si Ayanfẹ Agbegbe. Jẹ ki a ṣeto Iyanu Agbegbe lori Router7 ki o wo bii Router5 ṣe ṣe si eyi:
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>Nitorinaa, a ṣẹda maapu ipa-ọna ti o ni gbogbo awọn ipa-ọna ati sọ fun Router7 lati yi paramita Iyanfẹ Agbegbe pada si 250 nigbati o ba gba, aiyipada jẹ 100. Jẹ ki a wo ohun ti o ṣẹlẹ lori 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 iGẹgẹbi a ti le rii ni bayi Router5 fẹran ipa-ọna nipasẹ Router7. Aworan kanna yoo wa lori Router6, botilẹjẹpe o jẹ ere diẹ sii fun u lati yan ipa-ọna nipasẹ Router8. A tun ṣafikun pe yiyipada paramita yii nilo atunbere agbegbe fun iyipada lati mu ipa. Ka . A ti ṣeto Awọn ayanfẹ Agbegbe. Jẹ ki a lọ si paramita atẹle.
- Fẹ ipa ọna pẹlu paramita Next-hop 0.0.0.0, iyẹn ni, agbegbe tabi awọn ipa-ọna akojọpọ. Awọn ipa-ọna wọnyi ni a sọtọ laifọwọyi paramita iwuwo dogba si o pọju-32678-lẹhin titẹ aṣẹ nẹtiwọki:
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 - Ọna to kuru ju nipasẹ AS. A yan paramita AS_Path to kuru ju. Awọn ASs diẹ ti ọna kan lọ nipasẹ, o dara julọ. Wo ipa ọna si 9.9.9.0/24 lori 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 iBii o ti le rii, Router10 yan ipa ọna nipasẹ 192.168.112.12 nitori ipa ọna yii paramita AS_Path ni 45 nikan, ati ninu ọran miiran 123 ati 45. Ti o han gbangba.
- Nigbamii ti paramita ni Oti. IGP (ọna ti a gba nipa lilo BGP) dara ju EGP (ọna ti a gba ni lilo iṣaju BGP, ko si ni lilo mọ), ati pe EGP dara ju Ailopin lọ? (ti a gba nipasẹ ọna miiran, fun apẹẹrẹ nipasẹ pinpin).
- Nigbamii ti paramita ni MED. A ni Wieight ti o ṣiṣẹ nikan ni agbegbe lori olulana. Iyanfẹ Agbegbe wa, eyiti o ṣiṣẹ nikan laarin eto adase kan. Bi o ṣe le gboju, MED jẹ paramita kan ti yoo tan kaakiri laarin awọn eto adase. O dara pupọ nipa paramita yii.
Ko si awọn abuda diẹ sii ti yoo lo, ṣugbọn ti ipa-ọna meji ba ni awọn abuda kanna, lẹhinna awọn ofin wọnyi ni a lo:
- Yan ọna nipasẹ aladuugbo IGP to sunmọ.
- Yan ipa ọna atijọ julọ fun ọna eBGP.
- Yan ọna nipasẹ aladugbo pẹlu ID olulana BGP ti o kere julọ.
- Yan ọna nipasẹ aladugbo pẹlu adiresi IP ti o kere julọ.
Bayi jẹ ki ká wo ni oro ti BGP convergence.
Jẹ ki a wo ohun ti o ṣẹlẹ ti Router6 padanu ipa-ọna 9.9.9.0/24 nipasẹ Router9. Jẹ ki a mu wiwo Gi0/1 ti Router6 kuro, eyiti yoo loye lẹsẹkẹsẹ pe igba BGP pẹlu Router8 ti pari ati pe aladugbo ti sọnu, eyiti o tumọ si pe ọna ti o gba lati ọdọ rẹ ko wulo. Router6 firanṣẹ awọn ifiranṣẹ imudojuiwọn lẹsẹkẹsẹ, nibiti o tọka nẹtiwọki 9.9.9.0/24 ni aaye Awọn ipa ọna yiyọ kuro. Ni kete ti Router5 gba iru ifiranṣẹ bẹẹ, yoo firanṣẹ si Router7. Ṣugbọn niwọn igba ti Router7 ni ipa-ọna nipasẹ Router10, yoo dahun lẹsẹkẹsẹ pẹlu imudojuiwọn pẹlu ipa ọna tuntun kan. Ti ko ba ṣee ṣe lati rii isubu ti aladugbo ti o da lori ipo ti wiwo, lẹhinna o yoo ni lati duro fun Aago Idaduro lati ina.
Confederation.
Ti o ba ranti, a sọrọ nipa otitọ pe o nigbagbogbo ni lati lo topology ti o ni asopọ ni kikun. Pẹlu nọmba nla ti awọn onimọ-ọna ni AS eyi le fa awọn iṣoro nla, lati yago fun eyi o nilo lati lo awọn igbimọ. AS kan ti pin si ọpọlọpọ awọn ipin-AS, eyiti o fun wọn laaye lati ṣiṣẹ laisi ibeere ti topology ti o ni asopọ ni kikun.
Eyi ni ọna asopọ kan si eyi , ati iṣeto ni fun GNS3.
Fun apẹẹrẹ, pẹlu topology yii a yoo ni lati so gbogbo awọn olulana ni AS 2345 si ara wa, ṣugbọn lilo Confederation, a le ṣe agbekalẹ awọn ibatan isunmọ nikan laarin awọn olulana ti o sopọ taara si ara wọn. Jẹ ki a sọrọ nipa eyi ni awọn alaye. Ti a ba ni AS 2345 nikan, lẹhinna laForge ntẹriba gba a March lati Picard yoo sọ fun awọn olulana data и Ṣiṣẹ, ṣugbọn wọn kii yoo sọ fun olulana nipa rẹ Kirusi . Bakannaa awọn ipa-ọna ti a pin nipasẹ olulana funrararẹ laForge, kii yoo ti gbe lọ Kirusi bẹni Ṣiṣẹ-Ah, rara data.
Iwọ yoo ni lati tunto Ọna-Reflector tabi ibatan agbegbe ti o ni asopọ ni kikun. Nipa pipin AS 2345 kan si 4 sub-AS (2,3,4,5) fun olulana kọọkan, a pari pẹlu ọgbọn iṣẹ ṣiṣe ti o yatọ. Ohun gbogbo ti wa ni pipe apejuwe .
Awọn orisun:
- CCIE afisona ati Yipada v5.0 Official Cert Itọsọna, iwọn didun 2, karun Edition, Narbik Kocharians, Terry Vinson.
- aaye ayelujara
- aaye ayelujara .
orisun: www.habr.com