BGP IOS kommandoer Programmering af Routere

BGP IOS kommandoer Programmering af Routere

ibgp Router ID Routere inden for samme AS anvender Peer Routerens Loopback adresse Et loopback Interface er altid aktivt Hvis der er flere Loopback adresser, er det den højeste Loopback adresse. Hvis der ikke anvendes Loopback adresser, er det den højeste IP adresse på Routeren.

ebgp Router ID Routere med forskellige AS anvender Peer Routerens Interface adresse

ibgp og ebgp Peer adresser P1 101 102 P2 AS 65110 172.18.1/24 1 1 172.18.2/24 192.168.1.4/30 Lo0: 10.0.0.1 Lo1: 192.168.9.1 R1 13 5 6 R2 Lo0: 10.0.0.2 P1 192.168.1.12/30 101 102 P2 AS 65120 172.17.1/24 1 14 1 172.17.2/24 192.168.1.8/30 R3 9 10 R4 Lo0: 10.0.0.4

Update-source 192.168.1.4/30 Lo0: 10.0.0.1 Lo0: 10.0.0.2 R1 5 6 R2 hostname R1! interface loopback 0 ip address 10.0.0.1 255.255.255.255! router bgp 65000 neighbor 10.0.0.2 remote-as 65000 neighbor 10.0.0.2 update-source loopback 0 hostname R2! interface loopback 0 ip address 10.0.0.2 255.255.255.255! router bgp 65000 neighbor 10.0.0.1 remote-as 65000 neighbor 10.0.0.1 update-source loopback 0

no syncronization Som standard annoncerer ibgp kun netværk som også kan ses i IGP tabellen. Dette er der som oftest ikke brug for. Slås fra med kommandoen no syncronization router isis net 49.0000.0100.0000.0001.00! router bgp 65000 no synkronization neighbor 10.0.0.2 remote-as 65000 neighbor 10.0.0.2 update-source loopback 0

auto-summary Ved at indføre Route summerization reduceres størrelsen af Route tabellen BGP har auto-summary aktiveret default. BGP summerer subprefix til klassebaserede netværk Hvis et netværk redistribueres fra IGP ind i BGP accepteres kun det klassebaserede netværk. ( Klasse A, B eller C)

auto-summary Hvis der ikke anvendes summerization der anvendes måske VLSM skal auto-summary deaktiveres. router isis net 49.0000.0100.0000.0001.00! router bgp 65000 no synkronization neighbor 10.0.0.2 remote-as 65000 neighbor 10.0.0.2 update-source loopback 0 no auto-summary

BGP kommandoen network Med network kommandoen kan bestemmes, hvilke netværk der skal annonceres. Direkte forbundne netværk Statiske Router Dynamiske Router (Fra f.eks. IS-IS) Skal være i routetabellen Ellers annonceres de ikke

BGP kommandoen network Network network-number [mask network-mask] mask kan bruges hvis der ønskes at subnet skal annonceres. Netværk som læres med network kommandoen annonceres til alle neighbor Medmindre de filtreres network kommandoen bestemmer ikke hvilke interfaces der anvendes. (RIP,OSPF..)

Eksempel network 172.16.0.0/16 172.17.0.0/16 192.168.1.4/30 R1 5 6 R2 AS = 100 AS = 200 hostname R1! router bgp 100 neighbor 192.168.1.6 remote-as 200 network 172.16.0.0 mask 255.255.0.0 hostname R2! router bgp 200 neighbor 192.168.1.5 remote-as 100 network 172.17.0.0 mask 255.255.0.0

show ip bgp neighbors BGP neighbor is 192.168.100.13, remote AS 200, internal link BGP version 4, remote router ID 0.0.0.0 BGP state = Active Last read 00:00:00, last write 00:00:00, hold time is 180, keepalive interval is 60 seconds Message statistics: InQ depth is 0 OutQ depth is 0 Sent Rcvd Opens: 2 2 Notifications: 0 0 Updates: 0 2 Keepalives: 138 138 Route Refresh: 0 0 Total: 140 142 Der er ikke etableret en peer

show ip bgp neighbors BGP neighbor is 192.168.100.13, remote AS 200, internal link BGP version 4, remote router ID 192.168.100.13 BGP state = Established, up for 02:10:57 Last read 00:00:56, last write 00:00:56, hold time is 180, keepalive interval is 60 seconds Neighbor capabilities: Der er Route refresh: advertised and received(old & new) etableret Address family IPv4 Unicast: advertised and received en peer Message statistics: InQ depth is 0 OutQ depth is 0 Sent Rcvd Opens: 1 1 Notifications: 0 0 Updates: 0 1 Keepalives: 133 133 Route Refresh: 0 0 Total: 134 135

show ip bgp neighbor options Show ip bgp neighbor [address [ received-routes routes path regular expression dampened routes] Address Specicifer adresse hvor routen er lært

show ip bgp neighbor [option] Option address Received Routes Routes Advertised Routes Path Dampened Routes Betydning Specificer adresse hvor Routen er lært Viser alle modtagne Router. Både accepterede og afviste. Viser Router der er accepterede Viser Router som annonceres til naboer Bruges til at matche paths som er modtaget Viser Dampened Routes til naboer, hvis ens IP adresser er opgivet.

show ip bgp BGP neighbor is 192.168.100.13, remote AS 200, internal link BGP version 4, remote router ID 192.168.100.13 BGP state = Established, up for 02:10:57 Last read 00:00:56, last write 00:00:56, hold time is 180, keepalive interval is 60 seconds Neighbor capabilities: Der er Route refresh: advertised and received(old & new) etableret Address family IPv4 Unicast: advertised and received en peer Message statistics: InQ depth is 0 OutQ depth is 0 Sent Rcvd Opens: 1 1 Notifications: 0 0 Updates: 0 1 Keepalives: 133 133 Route Refresh: 0 0 Total: 134 135

show ip bgp neighbors Der er kommet 6 opdateringer H1R2#show ip bgp BGP table version is 6, local router ID is 192.168.100.12 Status codes: s suppressed, d damped, h history, * valid, > best, i - internal, r RIB-failure, S Stale Origin codes: i - IGP, e - EGP,? - incomplete Network Next Hop Metric LocPrf Weight Path *>i10.1.8.0/24 192.168.100.13 0 100 0 i

show ip route H1R2#show ip route Codes: 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 Gateway of last resort is not set C 172.21.0.0/16 is directly connected, FastEthernet0/1 10.0.0.0/24 is subnetted, 5 subnets B 10.1.8.0 [200/0] via 192.168.100.13, 00:10:09 C 10.1.7.0 is directly connected, Loopback4 C 10.1.6.0 is directly connected, Loopback3 C 10.1.5.0 is directly connected, Loopback2 C 10.1.4.0 is directly connected, Loopback1 C 192.168.1.0/24 is directly connected, FastEthernet0/0 192.168.100.0/32 is subnetted, 3 subnets C 192.168.100.12 is directly connected, Loopback0 i L2 192.168.100.13 [115/20] via 192.168.1.2, FastEthernet0/0 i L2 192.168.100.11 [115/20] via 172.21.0.2, FastEthernet0/1

Kommandoen: next-hop-self ibgp Routere ved ikke altid hvordan de skal Route til en ebgp Router Interne ibgp routere kender kun next-hop addresser de har lært fra en IGP Se eksempel næste slide 172.16.0.0/16 192.168.1.1 192.168.1.2 R1 R2 R3 Lo0: 8.8.8.8 Lo0: 7.7.7.7 Lo0: 2.2.2.2 AS = 3292 AS = 200

Kommandoen: next-hop-self R2 lærer nettet 172.16.0.0/16 fra ebgp naboen R3 Next-hop adressen er derfor 192.168.1.2 R1 lærer nettet fra R2 med next-hop 192.168.1.2 R2 kender ikke nettet 192.168.1.0/30 da det ikke deltager i IGP? 172.16.0.0/16 192.168.1.1 192.168.1.2 R1 R2 R3 Lo0: 8.8.8.8 Lo0: 7.7.7.7 Lo0: 2.2.2.2 AS = 3292 AS = 200

Kommandoen: next-hop-self hostname R1! router bgp 3292 no synchronization neighbor 7.7.7.7 remote-as 3292 neighbor 7.7.7.7 update-source loopback 0 172.16.0.0/16 192.168.1.1 192.168.1.2 R1 R2 R3 Lo0: 8.8.8.8 Lo0: 7.7.7.7 Lo0: 2.2.2.2 AS = 3292 AS = 200

Kommandoen: next-hop-self hostname R2! router bgp 3292 no synchronization neighbor 192.168.1.2 remote-as 200 neighbor 8.8.8.8 remote-as 3292 neighbor 8.8.8.8 update-source loopback 0 neighbor 8.8.8.8 next-hop-self 172.16.0.0/16 192.168.1.1 192.168.1.2 R1 R2 R3 Lo0: 8.8.8.8 Lo0: 7.7.7.7 Lo0: 2.2.2.2 AS = 3292 AS = 200

Kommandoen: next-hop-self hostname R3! router bgp 200 neighbor 192.168.1.1 remote-as 3292 172.16.0.0/16 192.168.1.1 192.168.1.2 R1 R2 R3 Lo0: 8.8.8.8 Lo0: 7.7.7.7 Lo0: 2.2.2.2 AS = 3292 AS = 200

Peering / Neighbors Indenfor et AS bliver netværk Routnings informationer der er lært via ibgp ikke videresendt. Hvis det blev videresendt kunne der opstå Routenings Loops Derfor skal alle ibgp Routere være forbundet logisk ikke nødvendigvis fysisk Full Meshed.