网络工程 - 路由表资格 - 吾爱随笔录

我有一个体系结构，即每个远程站点都有 2 个拨号器接口，可拨入虚拟模板核心，该核心对会话进行身份验证并应用来自 RADIUS 服务器的属性。OSPF 运行在拨号接口上（在远程站点上）并衍生出虚拟访问接口（来自核心路由器上的虚拟模板）并且 OSPF 邻居关系很好：

remote_router#show ip ospf neighbor

Neighbor ID     Pri   State           Dead Time   Address         Interface
10.200.0.6        0   FULL/  -        00:00:30    10.200.0.6      Dialer1
10.200.0.6        0   FULL/  -        00:00:24    10.200.0.6      Dialer2

但是没有 ECMP 操作：

    remote_router#show ip os database external 0.0.0.0

            OSPF Router with ID (10.200.0.32) (Process ID 2002)

                Type-5 AS External Link States

  LS age: 1521
  Options: (No TOS-capability, DC, Upward)
  LS Type: AS External Link
  Link State ID: 0.0.0.0 (External Network Number )
  Advertising Router: 10.200.0.6
  LS Seq Number: 800032A2
  Checksum: 0x525
  Length: 36
  Network Mask: /0
        Metric Type: 2 (Larger than any link state path)
        MTID: 0
        Metric: 1
        Forward Address: 0.0.0.0
        External Route Tag: 3489700465

您可以在此处看到两个接口的指标相同：

Dialer1 is up, line protocol is up (spoofing)
  Internet Address 10.200.0.53/32, Area 0.0.0.0, Attached via Interface Enable
  Process ID 2002, Router ID 10.200.0.32, Network Type POINT_TO_POINT, Cost: 1562
  Topology-MTID    Cost    Disabled    Shutdown      Topology Name
        0           1562      no          no            Base
  Enabled by interface config, including secondary ip addresses
  Transmit Delay is 1 sec, State POINT_TO_POINT
  Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5
    oob-resync timeout 40
    Hello due in 00:00:07
  Supports Link-local Signaling (LLS)
  Cisco NSF helper support enabled
  IETF NSF helper support enabled
  Index 1/1/5, flood queue length 0
  Next 0x0(0)/0x0(0)/0x0(0)
  Last flood scan length is 1, maximum is 5
  Last flood scan time is 0 msec, maximum is 0 msec
  Neighbor Count is 1, Adjacent neighbor count is 1
    Adjacent with neighbor 10.200.0.6
  Suppress hello for 0 neighbor(s)
  Simple password authentication enabled
Dialer2 is up, line protocol is up (spoofing)
  Internet Address 10.200.0.57/32, Area 0.0.0.0, Attached via Interface Enable
  Process ID 2002, Router ID 10.200.0.32, Network Type POINT_TO_POINT, Cost: 1562
  Topology-MTID    Cost    Disabled    Shutdown      Topology Name
        0           1562      no          no            Base
  Enabled by interface config, including secondary ip addresses
  Transmit Delay is 1 sec, State POINT_TO_POINT
  Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5
    oob-resync timeout 40
    Hello due in 00:00:07
  Supports Link-local Signaling (LLS)
  Cisco NSF helper support enabled
  IETF NSF helper support enabled
  Index 1/2/6, flood queue length 0
  Next 0x0(0)/0x0(0)/0x0(0)
  Last flood scan length is 1, maximum is 5
  Last flood scan time is 0 msec, maximum is 0 msec
  Neighbor Count is 1, Adjacent neighbor count is 1
    Adjacent with neighbor 10.200.0.6
  Suppress hello for 0 neighbor(s)
  Simple password authentication enabled

我认为正在发生的事情是因为广告路由器 (10.200.0.6) 在 Dialer1 和 Dialer2 上可用，OSPF 无法通过两个接口进行 ECMP，因为它认为路由相同，因此只会安装一条路由。我找不到任何文档或调试来证明情况确实如此，如果有人可以帮助我，我将不胜感激。

亲切的问候，

加雷斯