因缺少配置参数导致S5700交换机和C设备之间BFD会话无法UP

发布时间:  2014-09-12 浏览次数:  293 下载次数:  0
问题描述
配置完成以后,bfd session无法UP。
相关配置信息如下:
S5700配置如下:
bfd
bfd test bind peer-ip x.x.x.3 source-ip x.x.x.1 auto
#
interface Vlanif3127
ip address x.x.x.1 255.255.255.0
#
interface GigabitEthernet0/0/5
port link-type access
port default vlan 3127
C配置如下
interface GigabitEthernet1/11
ip address x.x.x.3 255.255.255.0
bfd interval 750 min_rx 750 multiplier 3
!
ip route static bfd GigabitEthernet1/11 x.x.x.1

ip route x.x.x.0 255.255.255.0 GigabitEthernet1/11 x.x.x.1

告警信息
查看S5700上的bfd session统计表项:
[S5700EI] display bfd statistics session all
--------------------------------------------------------------------------------
Session MIndex : 256       (Multi Hop) State : Down      Name : jiansheyinhang
--------------------------------------------------------------------------------
  Session Type                        : Static_Auto                           
  Bind Type                           : IP                                    
  Local/Remote Discriminator          : 8192/0                                
  Received Packets                    : 0                                     
  Send Packets                        : 182                                    
  Received Bad Packets                : 0                                     
  Send Bad Packets                    : 0                                     
  Down Count                          : 0                                      
  ShortBreak Count                    : 0                                     
  Send Lsp Ping Count                 : 0                                     
  Dynamic Session Delete Count        : 0                                     
  Create Time                         : 2013/03/2523:42:09                   
  Last Down Time                      : 0000/00/00 00:00:00                   
  Down Status Lasting Time            : 000D:00H:10M:35S                      
  Total Time From Create              : 000D:00H:10M:35S                      
--------------------------------------------------------------------------------

     Total Session Number : 1
发现表现一直是down,在Received Packets统计项没有对端发来的BFD控制包。
处理过程
1:ping对端直连地址,发现能够ping通,说明链路没有问题

2:通过在S5700交换机上面抓包发现有对端发来的bfd报文,说明S5700已经收到bfd控制包

3:采用同样的设备配置,发现我司的路由器和对端设备之间的bfd session能够up。

修改S5700上面的bd配置为:
bfd test bind peer-ip x.x.x.3 interface Vlanif3127 source-ip x.x.x.1 auto
修改之后在两端设备上查看bfd session表项:
华为:
[S5700EI]dis bfd session all                                                                                                             
--------------------------------------------------------------------------------                                                  
Local Remote     PeerIpAddr      State     Type        InterfaceName                                                              
--------------------------------------------------------------------------------                                                  
8193  1          x.x.x.3      Up        S_AUTO_IF   Vlanif3127                                                                 
--------------------------------------------------------------------------------                                                  
   Total UP/DOWN Session Number :1/0                                                                                           
[S5700EI]

C设备上:
C6509E#show bfd neighbors                                                                                                         
                                                                                                                                   
IPv4 Sessions                                                                                                                     
NeighAddr                              LD/RD         RH/RS     State     Int                                                      
x.x.x.1                              1/8193       Up        Up        Gi1/11 


可以发现bfd session表项建立正常。

根因
1:广域网链路down了。
2:对端设备没有发送bfd报文。
3:或者是设备配置问题。
建议与总结
问题产生原因:我司S5700交换机在配置接口地址时,只能配置在vlanif下,不支持在物理口下直接配置接口地址,所以在和对端设备配置BFD静态标识符自协商时,需要携带vlan号,否则物理口在收到对端送来的bfd控制包,在上送至CPU的时候会被丢弃,所以在display bfd statistics session all查看显示没有收到BFD控制包,BFD session无法up。

建议:在交换机上面配置BFD 静态标识符自协商时,一定要将本段接口vlan号携带上。


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