BGP 設定例
概要
BGP を使った冗長化設定例になります。
動作確認は R5 と R6 の Loopback インターフェース間の Ping 疎通により行っています。
検証環境
- CSR1000V を VMware Workstation 上に構築
- IOS は 15.4(1)S2を使用
通信フロー
正常系
故障系-1
故障系-2
故障系-3
設定例
R1
hostname R1 ! interface GigabitEthernet1 ip address 10.1.13.1 255.255.255.0 negotiation auto ! interface GigabitEthernet2 ip address 10.1.12.1 255.255.255.0 negotiation auto ! interface GigabitEthernet3 ip address 172.16.15.1 255.255.255.0 negotiation auto ! router ospf 1 redistribute bgp 65001 metric 100 metric-type 1 subnets network 172.16.15.0 0.0.0.255 area 0 ! router bgp 65001 bgp log-neighbor-changes timers bgp 10 30 neighbor 10.1.12.2 remote-as 65001 neighbor 10.1.13.3 remote-as 65002 ! address-family ipv4 bgp redistribute-internal network 192.168.5.0 neighbor 10.1.12.2 activate neighbor 10.1.12.2 next-hop-self neighbor 10.1.13.3 activate neighbor 10.1.13.3 route-map LP in neighbor 10.1.13.3 route-map MED out neighbor 10.1.13.3 filter-list 1 out exit-address-family ! ip as-path access-list 1 permit ^$ ip as-path access-list 2 permit ^65002_ ! access-list 1 permit 192.168.5.0 0.0.0.255 ! route-map LP permit 10 match as-path 2 set local-preference 200 ! route-map MED permit 10 match ip address 1 set metric 110 !
R2
hostname R2 ! interface GigabitEthernet1 ip address 10.1.24.2 255.255.255.0 negotiation auto ! interface GigabitEthernet2 ip address 10.1.12.2 255.255.255.0 negotiation auto ! interface GigabitEthernet3 ip address 172.16.25.2 255.255.255.0 negotiation auto ! router ospf 1 network 172.16.25.0 0.0.0.255 area 0 ! router bgp 65001 bgp log-neighbor-changes timers bgp 10 30 neighbor 10.1.12.1 remote-as 65001 neighbor 10.1.24.4 remote-as 65002 ! address-family ipv4 network 192.168.5.0 neighbor 10.1.12.1 activate neighbor 10.1.12.1 next-hop-self neighbor 10.1.24.4 activate neighbor 10.1.24.4 route-map LP in neighbor 10.1.24.4 route-map MED out neighbor 10.1.24.4 filter-list 1 out distance bgp 20 100 200 exit-address-family ! ip as-path access-list 1 permit ^$ ip as-path access-list 2 permit ^65002_ ! access-list 1 permit 192.168.5.0 0.0.0.255 ! route-map LP permit 10 match as-path 2 set local-preference 150 ! route-map MED permit 10 match ip address 1 set metric 120 !
R3
hostname R3 ! interface GigabitEthernet1 ip address 10.1.13.3 255.255.255.0 negotiation auto ! interface GigabitEthernet2 ip address 10.1.34.3 255.255.255.0 negotiation auto ! interface GigabitEthernet3 ip address 172.16.36.3 255.255.255.0 negotiation auto ! router ospf 1 redistribute bgp 65002 metric 100 metric-type 1 subnets network 172.16.36.0 0.0.0.255 area 0 ! router bgp 65002 bgp log-neighbor-changes timers bgp 10 30 neighbor 10.1.13.1 remote-as 65001 neighbor 10.1.34.4 remote-as 65002 ! address-family ipv4 bgp redistribute-internal network 192.168.6.0 neighbor 10.1.13.1 activate neighbor 10.1.13.1 route-map LP in neighbor 10.1.13.1 route-map MED out neighbor 10.1.13.1 filter-list 1 out neighbor 10.1.34.4 activate neighbor 10.1.34.4 next-hop-self exit-address-family ! ip as-path access-list 1 permit ^$ ip as-path access-list 2 permit ^65001_ ! access-list 1 permit 192.168.6.0 0.0.0.255 ! route-map LP permit 10 match as-path 2 set local-preference 200 ! route-map MED permit 10 match ip address 1 set metric 110 !
R4
hostname R4 ! interface GigabitEthernet1 ip address 10.1.24.4 255.255.255.0 negotiation auto ! interface GigabitEthernet2 ip address 10.1.34.4 255.255.255.0 negotiation auto ! interface GigabitEthernet3 ip address 172.16.46.4 255.255.255.0 negotiation auto ! router ospf 1 network 172.16.46.0 0.0.0.255 area 0 ! router bgp 65002 bgp log-neighbor-changes timers bgp 10 30 neighbor 10.1.24.2 remote-as 65001 neighbor 10.1.34.3 remote-as 65002 ! address-family ipv4 network 192.168.6.0 neighbor 10.1.24.2 activate neighbor 10.1.24.2 route-map LP in neighbor 10.1.24.2 route-map MED out neighbor 10.1.24.2 filter-list 1 out neighbor 10.1.34.3 activate neighbor 10.1.34.3 next-hop-self distance bgp 20 100 200 exit-address-family ! ip as-path access-list 1 permit ^$ ip as-path access-list 2 permit ^65001_ ! access-list 1 permit 192.168.6.0 0.0.0.255 ! route-map LP permit 10 match as-path 2 set local-preference 150 ! route-map MED permit 10 match ip address 1 set metric 120 !
R5
hostname R5 ! interface Loopback1 ip address 192.168.5.5 255.255.255.0 ip ospf network point-to-point ! interface GigabitEthernet1 ip address 172.16.15.5 255.255.255.0 negotiation auto ! interface GigabitEthernet2 ip address 172.16.25.5 255.255.255.0 negotiation auto ! router ospf 1 network 172.16.15.0 0.0.0.255 area 0 network 172.16.25.0 0.0.0.255 area 0 network 192.168.5.0 0.0.0.255 area 0 ! ip route 192.168.6.0 255.255.255.0 172.16.25.2 200 !
R6
hostname R6 ! interface Loopback1 ip address 192.168.6.6 255.255.255.0 ip ospf network point-to-point ! interface GigabitEthernet1 ip address 172.16.36.6 255.255.255.0 negotiation auto ! interface GigabitEthernet2 ip address 172.16.46.6 255.255.255.0 negotiation auto ! router ospf 1 network 172.16.36.0 0.0.0.255 area 0 network 172.16.46.0 0.0.0.255 area 0 network 192.168.6.0 0.0.0.255 area 0 ! ip route 192.168.5.0 255.255.255.0 172.16.46.4 200168.6.0 255.255.255.0 172.16.25.2 200 !
設定のポイント
R1(R3)
- IBGP の経路情報を OSPF へ再配送
address-family ipv4 bgp redistribute-internal
共通
- 他の AS の経路情報を配送しない。
address-family ipv4 neighbor 10.1.13.3 filter-list 1 out ! ip as-path access-list 1 permit ^$
動作確認
正常系
R1(R3)は、対向へ経路情報を配信
R1#show ip bgp neighbors 10.1.13.3 advertised-routes BGP table version is 4, local router ID is 192.168.1.221 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 *> 192.168.5.0 172.16.15.5 2 32768 i Total number of prefixes 1
R1(R3)は、対向から経路情報を受信
R1#show ip bgp neighbors 10.1.13.3 routes BGP table version is 4, local router ID is 192.168.1.221 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 *> 192.168.6.0 10.1.13.3 110 200 0 65002 i Total number of prefixes 1
R1(R3)は、LAN 内のネットワークについて OSPF 経由の経路を使用
R1#show ip route 192.168.5.0 longer-prefixes 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 Gateway of last resort is not set O 192.168.5.0/24 [110/2] via 172.16.15.5, 06:44:10, GigabitEthernet3
R1(R3)は、対向のネットワークについて BGP 経由の経路を使用
R1#show ip route 192.168.6.0 longer-prefixes 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 Gateway of last resort is not set B 192.168.6.0/24 [20/110] via 10.1.13.3, 00:29:35
R2(R4)は、対向のネットワークについて R1(R3)経由の経路を使用(LocPrf により優先)
R2#show ip bgp BGP table version is 3, local router ID is 192.168.1.222 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 192.168.5.0 10.1.12.1 2 100 0 i * 192.168.6.0 10.1.24.4 120 150 0 65002 i *>i 10.1.12.1 110 200 0 65002 i
故障系-1
R1(R3)は、対向のネットワークについて R2(R4)経由の経路へ変更
R1#show ip bgp BGP table version is 8, local router ID is 192.168.1.221 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 *> 192.168.5.0 172.16.15.5 2 32768 i *>i 192.168.6.0 10.1.12.2 120 150 0 65002 i
R2(R4)は、対向のネットワークについて R4(R2)経由の経路へ変更
R2#show ip bgp BGP table version is 4, local router ID is 192.168.1.222 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 192.168.5.0 10.1.12.1 2 100 0 i *> 192.168.6.0 10.1.24.4 120 150 0 65002 i
故障系-2
R1(R3)は、LAN 内のネットワークについて BGP 経由の経路へ変更
R1#show ip route 192.168.5.0 longer-prefixes 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 Gateway of last resort is not set B 192.168.5.0/24 [200/2] via 10.1.12.2, 00:13:30
R2(R4)は、LAN 内のネットワークについて OSPF 経由の経路へ変更
R2#show ip route 192.168.5.0 longer-prefixes 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 Gateway of last resort is not set O 192.168.5.0/24 [110/2] via 172.16.25.5, 00:24:05, GigabitEthernet3
故障系-3
R2(R4)は、LAN 内のネットワークについて OSPF 経由の経路へ変更
R2#show ip route 192.168.5.0 longer-prefixes 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 Gateway of last resort is not set O 192.168.5.0/24 [110/2] via 172.16.25.5, 00:24:05, GigabitEthernet3
R2(R4)は、対向のネットワークについて R4(R2)経由の経路へ変更
R2#show ip route 192.168.6.0 longer-prefixes 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 Gateway of last resort is not set B 192.168.6.0/24 [20/120] via 10.1.24.4, 00:06:25
R3は、対向のネットワークについて R4 経由の経路へ変更
R3#show ip bgp BGP table version is 8, local router ID is 192.168.1.223 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 192.168.5.0 10.1.34.4 120 150 0 65001 i *> 192.168.6.0 172.16.36.6 2 32768 i
R5(R6)は、対向のネットワークについて R2(R4)経由の経路へ変更
R5#show ip static route Codes: M - Manual static, A - AAA download, N - IP NAT, D - DHCP, G - GPRS, V - Crypto VPN, C - CASA, P - Channel interface processor, B - BootP, S - Service selection gateway DN - Default Network, T - Tracking object L - TL1, E - OER, I - iEdge D1 - Dot1x Vlan Network, K - MWAM Route PP - PPP default route, MR - MRIPv6, SS - SSLVPN H - IPe Host, ID - IPe Domain Broadcast U - User GPRS, TE - MPLS Traffic-eng, LI - LIIN IR - ICMP Redirect Codes in []: A - active, N - non-active, B - BFD-tracked, D - Not Tracked, P - permanent Static local RIB for default M 192.168.6.0/24 [200/0] via 172.16.25.2 [A]
以上
*1:OSPF(AD110)経由で学習した経路より IBGP 経由で学習した経路を優先するため。