VRRP don't pre-empt is not working as expected

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  • Updated 4 years ago
we use in ericsson equipments exterme LAN switches X450e. we normally have 2 switches with VRRP enabled between them. the configuration of VRRP is like below:

# Switch A (should be master)
create vrrp vlan SR_A_userplane vrid 216
configure vrrp vlan SR_A_userplane vrid 216 advertisement-interval 100 milliseconds
configure vrrp vlan SR_A_userplane vrid 216 priority 254
configure vrrp vlan SR_A_userplane vrid 216 dont-preempt
configure vrrp vlan SR_A_userplane vrid 216 add 172.19.136.67
enable vrrp vlan SR_A_userplane vrid 216

#Switch B (should be backup)
create vrrp vlan SR_A_userplane vrid 216
configure vrrp vlan SR_A_userplane vrid 216 advertisement-interval 100 milliseconds
configure vrrp vlan SR_A_userplane vrid 216 priority 253
configure vrrp vlan SR_A_userplane vrid 216 dont-preempt
configure vrrp vlan SR_A_userplane vrid 216 add 172.19.136.67
enable vrrp vlan SR_A_userplane vrid 216

the VLAN SR_A is configured on port 13 and the connection towards our customer routers are like the attached.



Within redundancy tests we face the following scenario:
1- the problem is when router A restarts router B becomes master and handles the traffic and when side A comes into service it becomes backup and no pre-emption is done.

2-when we try to disconnect cable (to simulate cable fault) connecting exterme router side A to customer router side A , exterme side A becomes in INIT state and B become master. when the cable was returned again side A becomes master again and pre-emption happened which means double failover that not required.

the software release of the switches is summitX-15.1.3.4-patch1-2

is it normal behaviour ? and if there is metigation in order not to have such behaviour can you
share it?

thanks
ayman
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ayman moussa

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Posted 4 years ago

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Andre Scott

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What about the config:
configure vrrp vlan SR_A_userplane vrid 216 priority 254

Doesnt that make side A priority?