配置BGP与IGP交互和路由自动聚合示例

组网需求

如图所示，用户将网络划分为AS65008和AS65009，在AS65009内，使用IGP协议来计算路由（该例使用OSPF做为IGP协议）。要求实现两个AS之间的互相通信。

配置思路

采用如下的思路配置BGP与IGP交互：

1. 在AR2、AR3和AR4上配置OSPF协议，使AR2、AR3和AR4之间可以互访。
2. 在AR1和AR2上配置EBGP连接，使AR1和AR2之间可以通过BGP相互传递路由。
3. 在AR2上配置BGP与OSPF互相引入，实现两个AS之间的互相通信。
4. 在AR2上配置BGP路由聚合，可以简化BGP路由表规模。

操作步骤

配置IP

AR1

<Huawei>sys
[Huawei]sys AR1[AR1]int g0/0/0
[AR1-GigabitEthernet0/0/0]ip add 12.12.12.1 24
[AR1-GigabitEthernet0/0/0]q[AR1]int lo1
[AR1-LoopBack1]ip add 1.1.1.1 24
[AR1-LoopBack1]q

AR2

<Huawei>sys
[Huawei]sys AR2[AR2]int g0/0/0
[AR2-GigabitEthernet0/0/0]ip add 12.12.12.2 24
[AR2-GigabitEthernet0/0/0]q[AR2]int g0/0/1
[AR2-GigabitEthernet0/0/1]ip add 10.10.23.2 24
[AR2-GigabitEthernet0/0/1]q

AR3

<Huawei>sys
[Huawei]sys AR3[AR3]int g0/0/0
[AR3-GigabitEthernet0/0/0]ip add 10.10.23.3 24
[AR3-GigabitEthernet0/0/0]q[AR3]int g0/0/1
[AR3-GigabitEthernet0/0/1]ip add 10.10.34.3 24
[AR3-GigabitEthernet0/0/1]q
[AR3]

AR4

<Huawei>sys
[Huawei]sys AR4[AR4]int g0/0/0
[AR4-GigabitEthernet0/0/0]ip add 10.10.34.4 24
[AR4-GigabitEthernet0/0/0]q

配置OSPF

AR2

[AR2]ospf
[AR2-ospf-1]area 0
[AR2-ospf-1-area-0.0.0.0]network 10.10.23.0 0.0.0.255
[AR2-ospf-1-area-0.0.0.0]q

AR3

[AR3]ospf
[AR3-ospf-1]area 0
[AR3-ospf-1-area-0.0.0.0]network 10.10.23.0 0.0.0.255
[AR3-ospf-1-area-0.0.0.0]network 10.10.34.0 0.0.0.255
[AR3-ospf-1-area-0.0.0.0]q

AR4

[AR4]ospf
[AR4-ospf-1]area 0
[AR4-ospf-1-area-0.0.0.0]network 10.10.34.0 0.0.0.255
[AR4-ospf-1-area-0.0.0.0]q

在AR4上查看OSPF路由表

[AR4-ospf-1]display ospf routingOSPF Process 1 with Router ID 10.10.34.4Routing Tables Routing for Network Destination        Cost  Type       NextHop         AdvRouter       Area10.10.34.0/24      1     Transit    10.10.34.4      10.10.34.4      0.0.0.010.10.23.0/24      2     Transit    10.10.34.3      12.12.12.2      0.0.0.0Total Nets: 2  Intra Area: 2  Inter Area: 0  ASE: 0  NSSA: 0 

配置BGP

AR1

[AR1]bgp 65008
[AR1-bgp]router-id 1.1.1.1
[AR1-bgp] peer 12.12.12.2 as-number 65009# 单播发布路由
[AR1-bgp] ipv4-family unicast
[AR1-bgp-af-ipv4]network 1.1.1.0 255.255.255.0

AR2

[AR2]bgp 65008
[AR2-bgp]router-id 2.2.2.2
[AR2-bgp] peer 12.12.12.1 as-number 65009

在AR2上查看BGP路由表

[AR2-bgp]display bgp routing-table BGP Local router ID is 2.2.2.2 Status codes: * - valid, > - best, d - damped,h - history,  i - internal, s - suppressed, S - StaleOrigin : i - IGP, e - EGP, ? - incompleteTotal Number of Routes: 1Network            NextHop        MED        LocPrf    PrefVal Path/Ogn*>   1.1.1.0/24         12.12.12.1      0                     0      65008i
[AR2-bgp]

配置路由引入

BGP路由引入到OSPF

AR2

[AR2]ospf
[AR2-ospf-1]import-route bgp 
[AR2-ospf-1]q

再次在AR4上查看OSPF路由表

<AR4>display ospf routing OSPF Process 1 with Router ID 10.10.34.4Routing Tables Routing for Network Destination        Cost  Type       NextHop         AdvRouter       Area10.10.34.0/24      1     Transit    10.10.34.4      10.10.34.4      0.0.0.010.10.23.0/24      2     Transit    10.10.34.3      12.12.12.2      0.0.0.0Routing for ASEsDestination        Cost      Type       Tag         NextHop         AdvRouter1.1.1.0/24         1         Type2      1           10.10.34.3      12.12.12.2Total Nets: 3  Intra Area: 2  Inter Area: 0  ASE: 1  NSSA: 0 <AR4>

OSPF路由引入到BGP

AR2

[AR2]bgp 65009
[AR2-bgp]ipv4-family unicast 
[AR2-bgp-af-ipv4]import-route ospf 1
[AR2-bgp-af-ipv4]q

再次在AR1上查看BGP路由表

<AR1>display bgp routing-table BGP Local router ID is 12.12.12.1 Status codes: * - valid, > - best, d - damped,h - history,  i - internal, s - suppressed, S - StaleOrigin : i - IGP, e - EGP, ? - incompleteTotal Number of Routes: 3Network            NextHop        MED        LocPrf    PrefVal Path/Ogn*>   1.1.1.0/24         0.0.0.0         0                     0      i*>   10.10.23.0/24      12.12.12.2      0                     0      65009?*>   10.10.34.0/24      12.12.12.2      2                     0      65009?

验证AS之间互通

AR4 ping AR1的LoopBack1

<AR4>ping 1.1.1.1PING 1.1.1.1: 56  data bytes, press CTRL_C to breakReply from 1.1.1.1: bytes=56 Sequence=1 ttl=253 time=60 msReply from 1.1.1.1: bytes=56 Sequence=2 ttl=253 time=30 msReply from 1.1.1.1: bytes=56 Sequence=3 ttl=253 time=40 msReply from 1.1.1.1: bytes=56 Sequence=4 ttl=253 time=40 msReply from 1.1.1.1: bytes=56 Sequence=5 ttl=253 time=40 ms--- 1.1.1.1 ping statistics ---5 packet(s) transmitted5 packet(s) received0.00% packet lossround-trip min/avg/max = 30/42/60 ms
#能ping即AS之间已互通

配置自动路由聚合

AR2

[AR2]bgp 65009
[AR2-bgp]ipv4-family unicast 
[AR2-bgp-af-ipv4]summary automatic 

AR1上查看路由表

<AR1>display bgp routing-table BGP Local router ID is 12.12.12.1 Status codes: * - valid, > - best, d - damped,h - history,  i - internal, s - suppressed, S - StaleOrigin : i - IGP, e - EGP, ? - incompleteTotal Number of Routes: 2Network            NextHop        MED        LocPrf    PrefVal Path/Ogn*>   1.1.1.0/24         0.0.0.0         0                     0      i*>   10.0.0.0           12.12.12.2                            0      65009?
<AR1>

聚合后再次验证互通

在AR1使用LoopBack1 ping AR4

<AR1>ping -a 1.1.1.1 10.10.34.4PING 10.10.34.4: 56  data bytes, press CTRL_C to breakReply from 10.10.34.4: bytes=56 Sequence=1 ttl=253 time=30 msReply from 10.10.34.4: bytes=56 Sequence=2 ttl=253 time=50 msReply from 10.10.34.4: bytes=56 Sequence=3 ttl=253 time=40 msReply from 10.10.34.4: bytes=56 Sequence=4 ttl=253 time=10 msReply from 10.10.34.4: bytes=56 Sequence=5 ttl=253 time=40 ms--- 10.10.34.4 ping statistics ---5 packet(s) transmitted5 packet(s) received0.00% packet lossround-trip min/avg/max = 10/34/50 ms<AR1>