关于OSPF宣告的路由与对端学习到的路由掩码不一致的问题记录

93 阅读 0 评论 62 点赞

我是靠谱客的博主愉快电话，最近开发中收集的这篇文章主要介绍关于OSPF宣告的路由与对端学习到的路由掩码不一致的问题记录，觉得挺不错的，现在分享给大家，希望可以做个参考。

概述

关于OSPF对端学习到的路由掩码与源设备上宣告的路由掩码不一致的问题记录

未解决

背景介绍:

整体拓扑
如图，A局点SD-WAN设备与A局点CISCO设备互联，CISCO设备为内网网关，通过SD-WAN，与其他站点内网互通。
B局点SD-WAN设备与B局点CISCO设备互联，CISCO设备为内网网关，通过SD-WAN，与其他站点内网互通。
CISCO设备与SD-WAN设备之间跑OSPF，通过在CISCO设备上宣告网段，使得其他局点动态得学习到该网段信息。

B局点点配置信息
SD-WAN配置：略。
CISCO设备配置：

Router#sh run | s ospf
router ospf 1
 log-adjacency-changes
 network 1.1.1.1 0.0.0.0 area 0
 network 10.10.0.0 0.0.3.255 area 0
 network 10.10.16.0 0.0.1.255 area 0
 network 10.10.60.0 0.0.0.255 area 0
 network 10.20.0.0 0.3.255.255 area 0
 network 10.100.130.0 0.0.0.255 area 0
 network 172.16.0.0 0.1.255.255 area 0
 network 192.168.8.0 0.0.0.255 area 0

查看SD-WAN设备的路由条目
路由1
在这里插入图片描述

发现路由条目对的上，但是掩码长度确不一致。
查看路由传递的信息。
B局点SD-WAN学习到的OSPF路由
A局点通过SD-WAN的OVERLAY网络学习到的路由
由此发现在B局点的SD-WAN设备上学习到的路由掩码长度和宣告的不一致，但是对端A局点SD-WAN设备依然从overlay网络学习到了该条长度不匹配的路由。

查看B局点的LSDB：

Router#sh ip ospf database router 1.1.1.1

            OSPF Router with ID (1.1.1.1) (Process ID 1)

                Router Link States (Area 0)

  LS age: 715
  Options: (No TOS-capability, DC)
  LS Type: Router Links
  Link State ID: 1.1.1.1
  Advertising Router: 1.1.1.1
  LS Seq Number: 800000AB
  Checksum: 0x3AE6
  Length: 132
  Number of Links: 9

    Link connected to: a Stub Network
     (Link ID) Network/subnet number: 1.1.1.1
     (Link Data) Network Mask: 255.255.255.255
      Number of MTID metrics: 0
       TOS 0 Metrics: 1

    Link connected to: a Stub Network
     (Link ID) Network/subnet number: 10.10.16.1
     (Link Data) Network Mask: 255.255.255.255
      Number of MTID metrics: 0
       TOS 0 Metrics: 1

    Link connected to: a Stub Network
     (Link ID) Network/subnet number: 10.20.0.1
     (Link Data) Network Mask: 255.255.255.255
      Number of MTID metrics: 0
       TOS 0 Metrics: 1

    Link connected to: a Stub Network
     (Link ID) Network/subnet number: 172.16.0.1
     (Link Data) Network Mask: 255.255.255.255
      Number of MTID metrics: 0
       TOS 0 Metrics: 1

    Link connected to: a Stub Network
     (Link ID) Network/subnet number: 10.100.130.1
     (Link Data) Network Mask: 255.255.255.255
      Number of MTID metrics: 0
       TOS 0 Metrics: 1

    Link connected to: a Stub Network
     (Link ID) Network/subnet number: 10.100.130.0
     (Link Data) Network Mask: 255.255.255.0
      Number of MTID metrics: 0
       TOS 0 Metrics: 1

    Link connected to: a Stub Network
     (Link ID) Network/subnet number: 192.168.8.1
     (Link Data) Network Mask: 255.255.255.255
      Number of MTID metrics: 0
       TOS 0 Metrics: 1

    Link connected to: a Stub Network
     (Link ID) Network/subnet number: 10.10.60.1
     (Link Data) Network Mask: 255.255.255.255
      Number of MTID metrics: 0
       TOS 0 Metrics: 1

    Link connected to: a Transit Network
     (Link ID) Designated Router address: 10.10.0.1
     (Link Data) Router Interface address: 10.10.0.1
      Number of MTID

查看LSA
Router#sh ip ospf database network

            OSPF Router with ID (1.1.1.1) (Process ID 1)

                Net Link States (Area 0)

  Routing Bit Set on this LSA in topology Base with MTID 0
  LS age: 1009
  Options: (No TOS-capability, DC)
  LS Type: Network Links
  Link State ID: 10.10.0.1 (address of Designated Router)
  Advertising Router: 1.1.1.1
  LS Seq Number: 80000078
  Checksum: 0x8AB9
  Length: 32
  Network Mask: /22
        Attached Router: 1.1.1.1
        Attached Router: 192.168.255.250

由此可见，在B局点的CISCO路由器LSDB中，宣告生效的路由即为：

1.1.1.1 
Mask: 255.255.255.255

10.10.16.1
Mask: 255.255.255.255
      

10.20.0.1
Mask: 255.255.255.255


172.16.0.1
 Mask: 255.255.255.255
 

10.100.130.1
 Mask: 255.255.255.255


10.100.130.0
Mask: 255.255.255.0

192.168.8.1
Mask: 255.255.255.255

10.10.60.1
Mask: 255.255.255.255

**因为B局点SD-WAN设备在学习的时候，与B局点CISCO设备LSDB中路由条目一致，掩码一致，而传递到对端的路由条目、掩码都与B局点SD-WAN设备一致，由此判断问题应该出现在B局点CISCO设备上。