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HSRP fails to work due to h/w failure

We have a situation that HSRP fails to work due to a partial h/w failure on the active router.

What happened is the active router continously getting input error on its Ethernet interface. User traffic fails to be received by this router. However the router is still able to send hello message to its standby router .When we do a sh standby on the active router, it says unknown standby which concluded that it does not receive hello message from the standby. The fault happened everyday . we can clear the problem by rebotting the router but fault came back the next day again for several times. Once we replaced the active router , problem did not return.

In understand HSRP uses mulitcast protocol . but I would like clarification that HSRP is using unidirectional comunication with the standby group. In a situation like this ,my assumption is the TX circuit on the LAN is working but teh RX circuit failed. The standby router would never know the LAN interface of actice router fails to receive its hello messages. Therefore the fail over never trigger.

Appreciate your feedback on this.




Re: HSRP fails to work due to h/w failure

I believe HSRP use multicast address for the hello but it still use broadcast to ensure the standby router is active. I can't find such info. to prove it. Please correct me if I am wrong.

For the LAN connection, if the RX is failed, the interface should not up, or say, e.g. if the RX-pair of cable is not connectioned, the interface should down. So, I believe there is something wrong in the LAN interface, it may not only the RX side error.

Just my 2 cents.

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