利用BGP虚拟下一跳技术实现IP骨干网流量负载均衡

1、配置 说明：【R1】interface Loopback0 ip address 192.168.0.1 255.255.255.255interface Serial1/0 no sh ip address 172.16.15.1 255.255.255.0interface Serial1/1 no sh ip address 172.16.12.1 255.255.255.0interface Serial1/2 no sh ip address 172.16.16.1 255.255.255.0interface Serial1/3 no sh ip address 172.16.13

2、.1 255.255.255.0ip route 10.0.0.1 255.255.255.255 172.16.13.3 【虚拟下一跳地址指向真正下一跳，并由本域内IGP(OSPF)路由引入，使本域内所有邻居都能学习到虚拟下一跳地址的路由，从而使邻居从自己学习到的路由能最优化】ip route 192.168.0.3 255.255.255.255 172.16.13.3ip prefix-list ISP-B seq 5 permit 172.16.34.0/24【做前缀列表匹配需要改变下一跳的前缀】route-map set-nexthop permit 10 【做route-map，改

3、相应前缀下一跳性】 match ip address prefix-list ISP-B set ip next-hop 10.0.0.1route-map set-nexthop permit 20router ospf 1 router-id 192.168.0.1 no auto-cost redistribute static metric 10 metric-type 1 subnets【引入静态路由，使域内所有IBGP邻居能学到虚拟下一跳地址，从面使邻居从自己学习到的路由能最优化】 network 172.16.12.0 0.0.0.255 area 0 network 172.1

4、6.15.0 0.0.0.255 area 0 network 172.16.16.0 0.0.0.255 area 0 network 192.168.0.0 0.0.0.255 area 0router bgp 100 no synchronization bgp router-id 192.168.0.1 bgp log-neighbor-changes neighbor internal peer-group neighbor internal remote-as 100 neighbor internal update-source Loopback0 neighbor intern

5、al route-map set-nexthop out【做出方向的ruout-map改变发向邻居路由的下一跳】 neighbor 192.168.0.2 peer-group internal neighbor 192.168.0.3 remote-as 200 neighbor 192.168.0.3 ebgp-multihop 255 neighbor 192.168.0.3 update-source Loopback0 neighbor 192.168.0.3 soft-reconfiguration inbound neighbor 192.168.0.5 peer-group i

6、nternal neighbor 192.168.0.6 peer-group internal no auto-summary【R2】interface Loopback0 ip address 192.168.0.2 255.255.255.255interface Serial1/0 no sh ip address 172.16.26.2 255.255.255.0interface Serial1/1 no sh ip address 172.16.12.2 255.255.255.0interface Serial1/2 no sh ip address 172.16.25.2 2

7、55.255.255.0interface Serial1/3 no sh ip address 172.16.24.2 255.255.255.0ip route 10.0.0.1 255.255.255.255 172.16.24.4【虚拟下一跳地址指向真正下一跳，并由本域内IGP(OSPF)路由引入，使本域内所有邻居都能学习到虚拟下一跳地址的路由，从而使邻居从自己学习到的路由能最优化】ip route 192.168.0.4 255.255.255.255 172.16.24.4ip prefix-list ISP-B seq 5 permit 172.16.34.0/24【做前缀列表匹

8、配需要改变下一跳的前缀】route-map set-nexthop permit 10【做route-map，改相应前缀下一跳性】 match ip address prefix-list ISP-B set ip next-hop 10.0.0.1route-map set-nexthop permit 20router ospf 1 router-id 192.168.0.2 log-adjacency-changes no auto-cost redistribute static metric 10 metric-type 1 subnets【引入静态路由，使域内所有IBGP邻居能学到

9、虚拟下一跳地址，从面使邻居从自己学习到的路由能最优化】 network 172.16.12.0 0.0.0.255 area 0 network 172.16.25.0 0.0.0.255 area 0 network 172.16.26.0 0.0.0.255 area 0 network 192.168.0.0 0.0.0.255 area 0router bgp 100 no synchronization bgp router-id 192.168.0.2 bgp log-neighbor-changes neighbor internal peer-group neighbor in

10、ternal remote-as 100 neighbor internal update-source Loopback0 neighbor internal route-map set-nexthop out【做出方向的ruout-map改变发向邻居路由的下一跳】 neighbor 192.168.0.1 peer-group internal neighbor 192.168.0.4 remote-as 200 neighbor 192.168.0.4 ebgp-multihop 255 neighbor 192.168.0.4 update-source Loopback0 neigh

11、bor 192.168.0.5 peer-group internal neighbor 192.168.0.6 peer-group internal no auto-summary【R3】由于R3、R4域内没有其它IBGP邻居，下挂设备都运行IGP所以不需要以虚拟下一跳的方式建立EBGP邻居，可以用正常的方式建立EBGP邻居即可interface Loopback0 ip address 192.168.0.3 255.255.255.255interface Serial1/0 no sh ip address 172.16.34.3 255.255.255.0interface Ser

12、ial1/3 no sh ip address 172.16.13.3 255.255.255.0router ospf 1 router-id 192.168.0.3 log-adjacency-changes no auto-cost network 172.16.34.0 0.0.0.255 area 0 network 192.168.0.0 0.0.0.255 area 0router bgp 200 no synchronization bgp router-id 192.168.0.3 bgp log-neighbor-changes network 1.0.0.0 networ

13、k 172.16.34.0 mask 255.255.255.0 neighbor 192.168.0.1 remote-as 100 neighbor 192.168.0.1 ebgp-multihop 255 neighbor 192.168.0.1 update-source Loopback0 neighbor 192.168.0.1 soft-reconfiguration inbound neighbor 192.168.0.4 remote-as 200 neighbor 192.168.0.4 update-source Loopback0 no auto-summaryip

14、route 0.0.0.0 0.0.0.0 172.16.13.1ip route 1.0.0.0 255.0.0.0 Null0ip route 192.168.0.1 255.255.255.255 172.16.13.1【R4】由于R3、R4域内没有其它IBGP邻居，下挂设备都运行IGP所以不需要以虚拟下一跳的方式建立EBGP邻居，可以用正常的方式建立EBGP邻居即可interface Loopback0 ip address 192.168.0.4 255.255.255.255interface Serial1/0 no sh ip address 172.16.34.4 255.2

15、55.255.0 serial restart-delay 0interface Serial1/3 no sh ip address 172.16.24.4 255.255.255.0 serial restart-delay 0router ospf 1 router-id 192.168.0.4 log-adjacency-changes no auto-cost network 172.16.34.0 0.0.0.255 area 0 network 192.168.0.0 0.0.0.255 area 0router bgp 200 no synchronization bgp ro

16、uter-id 192.168.0.4 bgp log-neighbor-changes network 1.0.0.0 network 172.16.34.0 mask 255.255.255.0 neighbor 192.168.0.2 remote-as 100 neighbor 192.168.0.2 ebgp-multihop 255 neighbor 192.168.0.2 update-source Loopback0 neighbor 192.168.0.3 remote-as 200 neighbor 192.168.0.3 update-source Loopback0 n

17、o auto-summaryip route 0.0.0.0 0.0.0.0 172.16.24.2ip route 1.0.0.0 255.0.0.0 Null0ip route 192.168.0.2 255.255.255.255 172.16.24.2【R5】R5、R6属于域内设备不建立EBGP邻居关系，也只要以正常方式与域内其它设备建立IBGP邻居关系即可interface Loopback0 ip address 192.168.0.5 255.255.255.255interface Serial1/0 no sh ip address 172.16.15.5 255.255.2

18、55.0interface Serial1/1 no sh ip address 172.16.56.5 255.255.255.0interface Serial1/2 no sh ip address 172.16.25.5 255.255.255.0router ospf 1 router-id 192.168.0.5 log-adjacency-changes no auto-cost network 172.16.0.0 0.0.255.255 area 0 network 192.168.0.0 0.0.0.255 area 0router bgp 100 no synchroni

19、zation bgp router-id 192.168.0.5 bgp log-neighbor-changes neighbor internal peer-group neighbor internal remote-as 100 neighbor internal update-source Loopback0 neighbor 192.168.0.1 peer-group internal neighbor 192.168.0.2 peer-group internal neighbor 192.168.0.6 peer-group internal no auto-summary【R6】R5、R6属于域内设备不建立EBGP邻居关系，也只要以正常方式与域内其它设备建立IBGP邻居关系即可interface Loopback0 ip address 192.168.0.6 255.255.255.255interface S