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Hot standby for a serial interface


There is a Cisco 3640 (lets say router A) with 8 T1 cards connecting 8 remote locations. L2 encapsulation is FR. This is a single point of failure and also one of the most critical routers. At the present moment, another Cisco 3640 is configured identically and replaces it in case of any hardware failure. The downtime is about 10 to 15 minutes as this is a co-located rack in a remote place. We have to call the tech over there to remove all the cables and connect them.

Is there any way to have a hot standby router for serial interfaces? There are protocols such as HSRP, VRRP for ethernet. Is there anything for serial links?

Let's say an ISDN dial backup is not an option.

What are my options?




Re: Hot standby for a serial interface

Hi Deepak,

I don't think HSRP and VRRP works on serial interface because HSRp and VRRP both work on the basis of virtual mac address or bia address and there is no concept of mac addresses for serial interfaces.

Will you having another 8 T1 lines for your second router? WHY I am asking is because if you want complete hardware redundancy there should be same lines terminating on another router also because unless and untill this criteria is met even if there is a way for serial interface redundancy and if first router crashes and you do not want any manual intervention then you have to have all 8 t1 lines also terminating on seciond router also.

If it is possible and you are planning to have some spare lines also available for second spare router what you can do is configure HSRP on lan interface and track your serial interfaces on primary router so that incase if primary router goes down completely or infact if only the serial lines go down all traffic can switch from primary router to the secondary router and traffic should pass from secondary router to the remote sites.



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