某局点VRRP非抢占模式重启后异常抢主

现场vrrp组网，两台S6850中间连心跳线跑vrrp，下联一台6800组成三角形的二层组网

两台设备相关配置如下：

主设备：

Interface vlan 192

Ip add 192.166.1.2 16

Vrrp vrid 1 virtual-ip 192.166.1.1

Vrrp vrid 1 priority 200

Undo vrrp vrid 1 preempt-mode

备设备：

Interface vlan 192

Ip add 192.166.1.3 16

Vrrp vrid 1 virtual-ip 192.166.1.1

Undo vrrp vrid 1 preempt-mode

如果只是shutdown/undo shutdown接口，vrrp主备不会发生高优先级抢占现象，但当主设备重启之后，主设备仍然会抢占成master。

*Feb 13 06:49:32:187 2001 6850-2-leaf VRRP4/7/Packet:

Sent Advertisement message from Vlan-interface192---主设备重启中，备设备变为主发送通告报文

VRID: 1  Pri: 100  Adver timer: 100 centisecs

*Feb 13 06:49:33:187 2001 6850-2-leaf VRRP4/7/Packet:

Sent Advertisement message from Vlan-interface192

VRID: 1  Pri: 100  Adver timer: 100 centisecs

*Feb 13 06:49:33:188 2001 6850-2-leaf VRRP4/7/Packet: Received Advertisement message from 192.166.1.2 on Vlan-interface192

VRID: 1  Pri: 200  Adver timer: 100 centisecs

%Feb 13 06:49:33:188 2001 6850-2-leaf VRRP4/6/VRRP_STATUS_CHANGE: The status of IPv4 virtual router 1 (configured on Vlan-interface192) changed from Master to Backup: VRRP packet received---重启主设备时在备设备上的日志

（1）  在实验室搭建相同的环境测试，跟现场的现象相同，查看log，重启主设备后，备设备变为master，主设备重启完成，心跳线1/0/1变为up状态，而在4s后才变为forwarding状态，此时已经超过了3s的超时时间，原主设备认为自己是主，往外发通告报文，主备根据优先级重新选举：

%Jan 21 01:29:00:290 2001 S6850-3 IFNET/3/PHY_UPDOWN: Physical state on the interface Twenty-FiveGigE1/0/1 changed to up.

%Jan 21 01:29:00:294 2001 S6850-3 IFNET/5/LINK_UPDOWN: Line protocol state on the interface Twenty-FiveGigE1/0/1 changed to up.

%Jan 21 01:29:00:433 2001 S6850-3 LLDP/6/LLDP_CREATE_NEIGHBOR: Nearest bridge agent neighbor created on port Twenty-FiveGigE1/0/1 (IfIndex 1), neighbor's chassis ID is a4fa-76d7-811e, port ID is Twenty-FiveGigE2/0/1.

%Jan 21 01:29:04:313 2001 S6850-3 STP/6/STP_FORWARDING: Instance 0's port Twenty-FiveGigE1/0/1 has been set to forwarding state –4s后变为转发状态

主设备上有如下日志：

%Feb 13 06:14:07:366 2001 6850-2-leaf LLDP/6/LLDP_CREATE_NEIGHBOR: Nearest bridge agent neighbor created on port Twenty-FiveGigE2/0/1 (IfIndex 196), neighbor's chassis ID is 80e4-55f6-413a, port ID is Twenty-FiveGigE1/0/1.

*Feb 13 06:14:10:667 2001 6850-2-leaf VRRP4/7/Event:

IPv4 Vlan-interface192 | Virtual Router 1 : Hold timer expired

%Feb 13 06:14:10:668 2001 6850-2-leaf VRRP4/6/VRRP_STATUS_CHANGE: The status of IPv4 virtual router 1 (configured on Vlan-interface192) changed from Backup to Master: Master-down-timer expired.

（2）  实验室也测试了在关闭心跳线两端端口stp的情况下，不会出现抢主情况；调整通告报文发送时间间隔为2s，超时时间为6s，也不会出现抢主现象：

%Jan 21 04:25:56:964 2001 S6850-3 IFNET/3/PHY_UPDOWN: Physical state on the interface Twenty-FiveGigE1/0/1 changed to up.

%Jan 21 04:25:56:965 2001 S6850-3 IFNET/5/LINK_UPDOWN: Line protocol state on the interface Twenty-FiveGigE1/0/1 changed to up.

%Jan 21 04:25:56:971 2001 S6850-3 LLDP/6/LLDP_CREATE_NEIGHBOR: Nearest bridge agent neighbor created on port Twenty-FiveGigE1/0/1 (IfIndex 1), neighbor's chassis ID is a4fa-76d7-811e, port ID is Twenty-FiveGigE2/0/1.

%Jan 21 04:26:01:301 2001 S6850-3 STP/6/STP_FORWARDING: Instance 0's port Twenty-FiveGigE1/0/1 has been set to forwarding state.

%Jan 21 04:26:01:301 2001 S6850-3 STP/6/STP_DETECTED_TC: Instance 0's port Twenty-FiveGigE1/0/1 detected a topology change.

%Jan 21 04:26:01:939 2001 S6850-3 STP/6/STP_NOTIFIED_TC: Instance 0's port Twenty-FiveGigE1/0/33 was notified a topology change.

%Jan 21 04:26:04:931 2001 S6850-3 STP/6/STP_NOTIFIED_TC: Instance 0's port Twenty-FiveGigE1/0/33 was notified a topology change.

[S6850-3]dis vrrp verbose

   Interface Vlan-interface192

     VRID             : 1                   Adver Timer  : 200      

     Admin Status     : Up                  State        : Master   

     Config Pri       : 100                 Running Pri  : 100      

     Preempt Mode     : No                

     Auth Type        : Not supported     

     Version          : 3

     Virtual IP       : 192.166.1.1                                  

     Virtual MAC      : 0000-5e00-0101

     Master IP        : 192.166.1.7   

经确认，现场的情况是由于设备重启后，在端口up后需要经过stp计算才会变为forwarding状态，导致在3s内没有收到对端的通告报文，超时重新形成vrrp造成的抢主现象，在家里也模拟复现了现场的情况。

可以通过关闭心跳线两端端口stp和调整通告报文发送时间间隔的方式来规避。