详解BSCI实验四：配置BGP
步骤一：配置三台路由器接口使其连通。
R1的配置
R1(config)# interface Loopback0
R1(config-if)# ip address 1.1.1 .1 255.255.255.0
R1(config)# interface Loopback1
R1(config-if)# ip address 2.2.2 .2 255.255.255.0
R1(config)# interface s0
R1(config-if)# ip address 10.1.1 .1 255.255.255.0
R1(config-if)#no shutdown
R1(config-if)#clock rate 64000
R2的配置
R2(config)#interface Loopback0
R2(config-if)# ip address 3.3.3 .3 255.255.255.0
R2(config)#interface Loopback1
R2(config-if)# ip address 4.4.4 .4 255.255.255.0
R2(config)#interface Serial0
R2(config-if)# ip address 20.1.1 .1 255.255.255.0
R2(config-if)#no shutdown
R2(config)#interface Serial1
R2(config-if)# ip address 10.1.1 .2 255.255.255.0
R2(config-if)#no shutdown
R3的配置
R3(config)#interface Loopback0
R3(config-if)# ip address 5.5.5 .5 255.255.255.0
R3(config)#interface Loopback1
R3(config-if)# ip address 6.6.6 .6 255.255.255.0
R3(config)#interface Serial1
R3(config-if)# ip address 20.1.1 .2 255.255.255.0
R3(config-if)#clockrate 64000
R3(config-if)#no shutdown
步骤二：启用
R1的配置
R1(config)#router eigrp 100 à启用eigrp100
R1(config-router)#network 1.1.1 .0 0.0.0.255 à发布相应接口
R1(config-router)#network 10.1.1 .0 0.0.0.255
R1(config-router)# no auto-summary à关闭自动汇总
R1(config)#router bgp 65001 à启用BGP65001
R1(config-router)#no synchronization à关闭与IGP的同步
R1(config-router)# network 2.2.2 .0 mask 255.255.255.0 à发布参与BGP网段
R1(config-router)# network 10.1.1 .0 mask 255.255.255.0
R1(config-router)# neighbor 3.3.3 .3 remote-as 65001 à指定邻居
R1(config-router)# neighbor 3.3.3 .3 update-source Loopback0 à更新源改为loop0接口
R1(config-router)#no auto-summary à关闭自动汇总
R2的配置
R2(config)#router eigrp 100
R2(config-router)# network 3.3.3 .0 0.0.0.255
R2(config-router)# network 10.1.1 .0 0.0.0.255
R2(config-router)# no auto-summary
R2(config)#router bgp 65001
R2(config-router)# no synchronization
R2(config-router)# network 4.4.4 .0 mask 255.255.255.0
R2(config-router)# network 10.1.1 .0 mask 255.255.255.0
R2(config-router)# neighbor 1.1.1 .1 remote-as 65001
R2(config-router)# neighbor 1.1.1 .1 update-source Loopback0
R2(config-router)# neighbor 1.1.1 .1 next-hop-self à将自己指定为邻居的下一跳
R2(config-router)# neighbor 5.5.5 .5 remote-as 65002 à指定ebgp邻居
R2(config-router)# neighbor 5.5.5 .5 ebgp-multihop 255 à设定多跳，默认为1
R2(config-router)# neighbor 5.5.5 .5 update-source Loopback0
R2(config-router)# no auto-summary
R3的配置
R3(config)#router bgp 65002
R3(config-router)#network 6.6.6 .0 mask 255.255.255.0
R3(config-router)# neighbor 3.3.3 .3 remote-as 65001
R3(config-router)# neighbor 3.3.3 .3 ebgp-multihop 255
R3(config-router)# neighbor 3.3.3 .3 update-source Loopback0
R3(config-router)# no auto-summary
步骤三：配置静态路由
R2(config)# ip route 5.5.5 .0 255.255.255.0 20.1.1.2 à因R2和R3运行在不同的AS，所以要指静态路由来达到可达性
R3(config)# ip route 3.3.3 .0 255.255.255.0 20.1.1.1 à同理
步骤四：查看路由表
R1#sh ip route
Codes: C - connected, S - static, I - IGRP, 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, E - EGP
i - IS-IS, 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
1.0.0 .0/24 is subnetted, 1 subnets
C 1.1.1 .0 is directly connected, Loopback0
2.0.0 .0/24 is subnetted, 1 subnets
C 2.2.2 .0 is directly connected, Loopback1
3.0.0 .0/24 is subnetted, 1 subnets
D 3.3.3 .0 [90/2297856] vi a 10.1.1 .2, 00:09:13, Serial0
4.0.0 .0/24 is subnetted, 1 subnets
B 4.4.4 .0 [200/0] via 3.3.3.3, 00:07:34 à学来了BGP路由条目
6.0.0 .0/24 is subnetted, 1 subnets
B 6.6.6 .0 [200/0] via 3.3.3.3, 00:07:34
10.0.0 .0/24 is subnetted, 1 subnets
C 10.1.1 .0 is directly connected, Serial0
R2#sh ip route
Codes: C - connected, S - static, I - IGRP, 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, E - EGP
i - IS-IS, 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
1.0.0 .0/24 is subnetted, 1 subnets
D 1.1.1 .0 [90/2297856] vi a 10.1.1 .1, 00:14:09, Serial1
2.0.0 .0/24 is subnetted, 1 subnets
B 2.2.2 .0 [200/0] via 1.1.1.1, 00:14:05
3.0.0 .0/24 is subnetted, 1 subnets
C 3.3.3 .0 is directly connected, Loopback0
4.0.0 .0/24 is subnetted, 1 subnets
C 4.4.4 .0 is directly connected, Loopback1
20.0.0 .0/24 is subnetted, 1 subnets
C 20.1.1 .0 is directly connected, Serial0
5.0.0 .0/24 is subnetted, 1 subnets
S 5.5.5 .0 [1/0] vi a 20.1.1 .2
6.0.0 .0/24 is subnetted, 1 subnets
B 6.6.6 .0 [20/0] via 5.5.5.5, 00:18:07
10.0.0 .0/24 is subnetted, 1 subnets
C 10.1.1 .0 is directly connected, Serial1
R3#sh ip route
Codes: C - connected, S - static, I - IGRP, 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, E - EGP
i - IS-IS, 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
2.0.0 .0/24 is subnetted, 1 subnets
B 2.2.2 .0 [20/0] via 3.3.3.3, 00:18:06
3.0.0 .0/24 is subnetted, 1 subnets
S 3.3.3 .0 [1/0] vi a 20.1.1 .1
4.0.0 .0/24 is subnetted, 1 subnets
B 4.4.4 .0 [20/0] via 3.3.3.3, 00:22:07
20.0.0 .0/24 is subnetted, 1 subnets
C 20.1.1 .0 is directly connected, Serial1
5.0.0 .0/24 is subnetted, 1 subnets
C 5.5.5 .0 is directly connected, Loopback0
6.0.0 .0/24 is subnetted, 1 subnets
C 6.6.6 .0 is directly connected, Loopback1
10.0.0 .0/24 is subnetted, 1 subnets
B 10.1.1 .0 [20/0] via 3.3.3.3, 00:22:09
步骤五：查看bgp 概要信息
R1#sh ip bgp summary
BGP router identifier 2.2.2 .2, local AS number 65001
Neighbor V AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down State/PfxRcd
3.3.3 .3 4 65001 13 12 5 0 0 00:08:23 3
R2#sh ip bgp summary
BGP router identifier 4.4.4 .4, local AS number 65001
Neighbor V AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down State/PfxRcd
1.1.1 .1 4 65001 18 19 5 0 0 00:14:41 2
5.5.5 .5 4 65002 22 23 5 0 0 00:18:42 1
R3#sh ip bgp summary
BGP router identifier 6.6.6 .6, local AS number 65002
NeighborV AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down State/PfxRcd
3.3.3 .3 4 65001 27 26 5 0 0 00:22:36 3
步骤六：查看bgp邻居
R1#sh ip bgp neighbors
BGP neighbor is 3.3.3 .3, remote AS 65001, internal link
BGP version 4, remote router ID 4.4.4 .4
BGP state = Established, up for 00:10:41 àIBGP邻居已建立
Last read 00:00:41, hold time is 180, keepalive interval is 60 seconds
R2#sh ip bgp neighbors
BGP neighbor is 1.1.1 .1, remote AS 65001, internal link
BGP version 4, remote router ID 2.2.2 .2
BGP state = Established, up for 00:15:15 àIBGP邻居已建立
BGP neighbor is 5.5.5 .5, remote AS 65002, external link
BGP version 4, remote router ID 6.6.6 .6
BGP state = Established, up for 00:19:25 àEBGP邻居已建立
R3#sh ip bgp neighbors
BGP neighbor is 3.3.3 .3, remote AS 65001, external link
BGP version 4, remote router ID 4.4.4 .4
BGP state = Established, up for 00:22:59 àEBGP邻居已建立
步骤七：查看bgp转发表
R1#sh ip bgp
BGP table version is 5, local router ID is 2.2.2 .2
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal
Origin codes: i - IGP, e - EGP, ? - incomplete
Network Next Hop Metric LocPrf Weight Path
*> 2.2.2 .0/24 0.0.0 .0 0 32768 i
*>i 4.4.4 .0/24 3.3.3 .3 0 100 0 i
*>i 6.6.6 .0/24 3.3.3 .3 0 100 0 65002 i
* i 10.1.1 .0/24 3.3.3 .3 0 100 0 i
*> 0.0.0 .0 0 32768 i
R2#sh ip bgp
BGP table version is 5, local router ID is 4.4.4 .4
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal
Origin codes: i - IGP, e - EGP, ? - incomplete
Network Next Hop Metric LocPrf Weight Path
*>i 2.2.2 .0/24 1.1.1 .1 0 100 0 i
*> 4.4.4 .0/24 0.0.0 .0 0 32768 i
*> 6.6.6 .0/24 5.5.5 .5 0 0 65002 i
* i 10.1.1 .0/24 1.1.1 .1 0 100 0 i
*> 0.0.0 .0 0 32768 i
R3#sh ip bgp
BGP table version is 5, local router ID is 6.6.6 .6
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal
Origin codes: i - IGP, e - EGP, ? - incomplete
Network Next Hop Metric LocPrf Weight Path
*> 2.2.2 .0/24 3.3.3 .3 0 65001 i
*> 4.4.4 .0/24 3.3.3 .3 0 0 65001 i
*> 6.6.6 .0/24 0.0.0 .0 0 32768 i
*> 10.1.1 .0/24 3.3.3 .3 0 0 65001 i
步骤八：用ping命令测试连通性或用扩展ping命令
R1#ping 6.6.6 .6
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 60/60/64 ms
R1#ping 4.4.4 .4
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 32/32/32 ms
R2#ping 2.2.2 .2
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 32/32/32 ms
R3#ping 2.2.2 .2
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 60/60/60 ms
r3#ping 4.4.4 .4
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 32/32/32 ms
步骤九：查看配置
R1#sh run
hostname R1
!
interface Loopback0
ip address 1.1.1 .1 255.255.255.0
!
interface Loopback1
ip address 2.2.2 .2 255.255.255.0
!
interface Serial0
ip address 10.1.1 .1 255.255.255.0
clockrate 64000
!
router eigrp 100
network 1.1.1 .0 0.0.0.255
network 10.1.1 .0 0.0.0.255
no auto-summary
!
router bgp 65001
no synchronization
network 2.2.2 .0 mask 255.255.255.0
network 10.1.1 .0 mask 255.255.255.0
neighbor 3.3.3 .3 remote-as 65001
neighbor 3.3.3 .3 update-source Loopback0
no auto-summary
!
end
R2#sh run
hostname R2
!
interface Loopback0
ip address 3.3.3 .3 255.255.255.0
!
interface Loopback1
ip address 4.4.4 .4 255.255.255.0
!
interface Serial0
ip address 20.1.1 .1 255.255.255.0
!
interface Serial1
ip address 10.1.1 .2 255.255.255.0
!
router eigrp 100
network 3.3.3 .0 0.0.0.255
network 10.1.1 .0 0.0.0.255
no auto-summary
!
router bgp 65001
no synchronization
network 4.4.4 .0 mask 255.255.255.0
network 10.1.1 .0 mask 255.255.255.0
neighbor 1.1.1 .1 remote-as 65001
neighbor 1.1.1 .1 update-source Loopback0
neighbor 1.1.1 .1 next-hop-self
neighbor 5.5.5 .5 remote-as 65002
neighbor 5.5.5 .5 ebgp-multihop 255
neighbor 5.5.5 .5 update-source Loopback0
no auto-summary
!
ip route 5.5.5 .0 255.255.255.0 20.1.1.2
！
end
R3#sh run
Hostname R3
!
interface Loopback0
ip address 5.5.5 .5 255.255.255.0
!
interface Loopback1
ip address 6.6.6 .6 255.255.255.0
!
interface Serial1
ip address 20.1.1 .2 255.255.255.0
clockrate 64000
!
router bgp 65002
network 6.6.6 .0 mask 255.255.255.0
neighbor 3.3.3 .3 remote-as 65001
neighbor 3.3.3 .3 ebgp-multihop 255
neighbor 3.3.3 .3 update-source Loopback0
no auto-summary
!
ip route 3.3.3 .0 255.255.255.0 20.1.1.1
end