网络工程 - 在没有 IGP 的情况下运行 iBGP - 吾爱随笔录

鉴于以下设置：

路由器的配置非常简单。路由器 BGP1：

interface Loopback0
 ip address 1.1.1.1 255.255.255.255
!
interface Loopback9
 ip address 9.9.9.9 255.255.255.255
!
interface GigabitEthernet0/1
 ip address 10.0.0.1 255.255.255.0
!
router bgp 1
 bgp log-neighbor-changes
 redistribute connected
 neighbor 10.0.0.2 remote-as 1
 neighbor 10.0.0.2 next-hop-self

路由器 BGP2：

interface Loopback0
 ip address 2.2.2.2 255.255.255.255
!
interface GigabitEthernet0/1
 ip address 10.0.0.2 255.255.255.0
!
interface GigabitEthernet0/3
 ip address 20.0.0.1 255.255.255.0
!
router bgp 1
 bgp log-neighbor-changes
 redistribute connected
 neighbor 10.0.0.1 remote-as 1
 neighbor 10.0.0.1 next-hop-self
 neighbor 20.0.0.2 remote-as 1
 neighbor 20.0.0.2 next-hop-self

路由器 BGP3：

interface Loopback0
 ip address 3.3.3.3 255.255.255.255
!
interface GigabitEthernet0/3
 ip address 20.0.0.2 255.255.255.0
!
router bgp 1
 bgp log-neighbor-changes
 redistribute connected
 neighbor 20.0.0.1 remote-as 1
 neighbor 20.0.0.1 next-hop-self

所以我将接口 loopback9 添加到路由器 BGP1 以查看它是否通过 BGP3。但这种情况并非如此。我可以看到从 BGP1 进入 BGP2 的路由：

BGP2#show ip route bgp | begin 1.0
      1.0.0.0/32 is subnetted, 1 subnets
B        1.1.1.1 [200/0] via 10.0.0.1, 00:10:07
      3.0.0.0/32 is subnetted, 1 subnets
B        3.3.3.3 [200/0] via 20.0.0.2, 00:10:07
      9.0.0.0/32 is subnetted, 1 subnets
B        9.9.9.9 [200/0] via 10.0.0.1, 00:10:07

但这不会被通告给路由器 BGP3：

BGP2#show ip bgp neighbors 20.0.0.2 advertised-routes | begin Networ
     Network          Next Hop            Metric LocPrf Weight Path
 *>  2.2.2.2/32       0.0.0.0                  0         32768 ?
 *>  10.0.0.0/24      0.0.0.0                  0         32768 ?
 *>  20.0.0.0/24      0.0.0.0                  0         32768 ?

在所有设备上禁用 IGP 同步：

BGP2# show ip protocols | include synch
  IGP synchronization is disabled

那么我该如何解决这个问题？我知道您应该在 BGP 下运行 IGP，但让我们假设在这种情况下这是不可能的。我有哪些选择？