如下图示:
R1通过R4获取上游路由。 R2通过R5获取上游路由。 配置操作如下: R1: interface FastEthernet0/0 ip address 13.1.1.1 255.255.255.0 router ospf 1 network 13.1.1.0 0.0.0.255 area 0 R2: interface FastEthernet0/1 ip address 23.1.1.2 255.255.255.0 router ospf 1 network 23.1.1.0 0.0.0.255 area 0 R3: interface FastEthernet0/0 ip address 13.1.1.3 255.255.255.0 ip policy route-map r1 interface FastEthernet0/1 ip address 23.1.1.3 255.255.255.0 ip policy route-map r2 interface FastEthernet1/0 ip address 34.1.1.3 255.255.255.0 interface FastEthernet1/1 ip address 35.1.1.3 255.255.255.0 router ospf 1 network 13.1.1.0 0.0.0.255 area 0 network 23.1.1.0 0.0.0.255 area 0 network 34.1.1.0 0.0.0.255 area 0 network 35.1.1.0 0.0.0.255 area 0 access-list 1 permit 13.1.1.0 0.0.0.255 access-list 2 permit 23.1.1.0 0.0.0.255 route-map r1 permit 10 match ip address 1 set ip precedence priority set ip next-hop 34.1.1.4 route-map r2 permit 10 match ip address 2 set ip precedence critical set ip next-hop 35.1.1.5 R4: interface FastEthernet0/0 ip address 45.1.1.4 255.255.255.0 interface FastEthernet0/1 ip address 34.1.1.4 255.255.255.0 router ospf 1 network 34.1.1.0 0.0.0.255 area 0 network 45.1.1.0 0.0.0.255 area 0 R5: interface FastEthernet0/0 ip address 45.1.1.5 255.255.255.0 interface FastEthernet0/1 ip address 35.1.1.5 255.255.255.0 router ospf 1 network 35.1.1.0 0.0.0.255 area 0 network 45.1.1.0 0.0.0.255 area 0 R1#traceroute 45.1.1.5 Type escape sequence to abort. Tracing the route to 45.1.1.5 1 13.1.1.3 28 msec 12 msec 12 msec 2 34.1.1.4 32 msec 32 msec 48 msec 3 45.1.1.5 44 msec 56 msec 48 msec R2#traceroute 45.1.1.4 Type escape sequence to abort. Tracing the route to 45.1.1.4 1 23.1.1.3 16 msec 12 msec 12 msec 2 35.1.1.5 40 msec 36 msec 32 msec 3 45.1.1.4 40 msec 32 msec 24 msec