NE20E bfd单臂回声功能无法up

发布时间:  2016-12-20 浏览次数:  140 下载次数:  0
问题描述
NE40E---(0/2/0)NE20E(0/1/0)---(10.25.31.2)H3C
NE20E V800R007C10SPC100
NE20E对NE40E的单臂回声功能可以up,对H3C的单臂回声功能无法up,ping正常
大致配置如下:
#
bfd 10 bind peer-ip 10.31.2.37 interface GigabitEthernet0/2/0 one-arm-echo
 discriminator local 10
#
bfd 200 bind peer-ip 10.25.31.2 interface GigabitEthernet0/1/0 source-ip 10.25.31.5 one-arm-echo
 discriminator local 200
#
处理过程
1、查看配置无问题,ping正常排除链路原因,中间无防火墙之类过滤设备,bfd echo报文理论上收发都没限制,当前bfd不up,只可能bfd echo交互失败:
  a、查看BFD计数,发现故障BFD只有发包,没有收包。而作为对比,bfd10接口的BFD会话收发包数量基本一致,初步确认对端问题:
<HUAWEI> display bfd statistics session all

--------------------------------------------------------------------------------
  (One Hop) State : Up       Name : 10    
--------------------------------------------------------------------------------
  Session Type                        : Static
  Bind Type                           : IP
  Local/Remote Discriminator          : 10/-
  Received Packets                    : 12859491        
  Send Packets                        : 12859507    
  Received Bad Packets                : 0        
  Send Bad Packets                    : 0       
  Down Count                          : 0
  ShortBreak Count                    : 0
  Send Lsp Ping Count                 : 0
  Create Time                         : 2016/11/15 08:34:15       
  Last Down Time                      : -
  Down Status Lasting Time            : ---D:--H:--M:--S
  Total Time From Create              : 001D:14H:30M:44S
--------------------------------------------------------------------------------

--------------------------------------------------------------------------------
  (One Hop) State : Up       Name : 20    
--------------------------------------------------------------------------------
  Session Type                        : Static
  Bind Type                           : IP
  Local/Remote Discriminator          : 200/-
  Received Packets                    : 0        
  Send Packets                        : 3813     
  Received Bad Packets                : 0        
  Send Bad Packets                    : 0       
  Down Count                          : 0
  ShortBreak Count                    : 0
  Send Lsp Ping Count                 : 0
  Create Time                         : 2012/03/23 08:34:15       
  Last Down Time                      : -
  Down Status Lasting Time            : ---D:--H:--M:--S
  Total Time From Create              : 000D:17H:10M:44S
--------------------------------------------------------------------------------

     Total Session Number :  2
 b、继续查看底层流统情况,发现0/1/0没有收到对端的回包。而0/2/0一直有回包,确定对端未响应echo导致会话无法up
<HUAWEI> display traffic policy statistics interface gigabitethernet 0/1/0 inbound verbose rule

Info: The statistics is shared because the policy is shared.
Interface: GigabitEthernet0/1/0
Traffic policy inbound: test2
Traffic policy applied at 2016-11-17 18:30:20
Statistics enabled at 2016-11-17 18:30:20
Statistics last cleared: Never
Rule number: 7 IPv4, 1 IPv6
Current status: OK!

Classifier: test2 operator or
 if-match acl 3000
  rule 5 permit udp destination 10.25.31.2 0 destination-port eq 3784
    0 bytes, 0 packets
    Last 30 seconds rate 0 pps, 0 bps
  rule 10 permit udp destination 10.25.31.5 0 destination-port eq 3784
    0 bytes, 0 packets
    Last 30 seconds rate 0 pps, 0 bps
  rule 11 permit udp destination 10.31.2.38 0 destination-port eq 3784                //有收到对端的回包
    3,273,864 bytes, 49,604 packets
    Last 30 seconds rate 0 pps, 0 bps
  rule 12 permit udp destination 10.31.2.37 0 destination-port eq 3784
    0 bytes, 0 packets
    Last 30 seconds rate 0 pps, 0 bps
<HUAWEI> display traffic policy statistics interface gigabitethernet 0/2/0 inbound verbose rule

Info: The statistics is shared because the policy is shared.
Interface: GigabitEthernet0/2/0
Traffic policy inbound: test2
Traffic policy applied at 2016-11-17 18:31:20
Statistics enabled at 2016-11-17 18:31:20
Statistics last cleared: Never
Rule number: 7 IPv4, 1 IPv6
Current status: OK!

Classifier: test2 operator or
 if-match acl 3000
  rule 5 permit udp destination 10.25.31.2 0 destination-port eq 3784             //底层计数一直未收到对端回包计数
    0 bytes, 0 packets                                         
    Last 30 seconds rate 0 pps, 0 bps
  rule 10 permit udp destination 10.25.31.5 0 destination-port eq 3784
    0 bytes, 0 packets
    Last 30 seconds rate 0 pps, 0 bps
  rule 11 permit udp destination 10.31.2.38 0 destination-port eq 3784
    3,273,864 bytes, 49,604 packets
    Last 30 seconds rate 0 pps, 0 bps
  rule 12 permit udp destination 10.31.2.37 0 destination-port eq 3784
    0 bytes, 0 packets
    Last 30 seconds rate 0 pps, 0 bps
根因

H3C不支持响应BFD echo报文导致会话无法up

解决方案
确认友商设备不支持,更换对端设备解决
建议与总结

BFD探测报文的源目的IP地址都是自己,由于部分尝试不支持响应这种报文,请配置时先确认对端是否支持响应,避免做无用功

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