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Duplicate address recieved

Hello,

We had an incident recently where a router expectantly reloaded - while it restarted the logs on all adjacent routers received the following message in their log:

%TAGCON-3-DUP_ADDR_RCVD: Duplicate Address 10.1.1.254 advertised by peer 192.168.63.252:0 is already bound to 192.168.60.251:0

I understand why this error occurred - it's because I have the same loopback IP addresses on multiple routers and the reason for this is we have DSL customers who have BGP sessions with us and can authenticate to any of 6 routers.  The loopback IP is the IP address that their BGP session is set to peer with, and since they could 'land' on any one of six routers I need to have that same loopback on all six routers.

Is there a better way to implement what I have and still achieve the same goal or filter out the prefixes that LDP advertises? - I know there is a command like the below, but this doesn't appear to do the filtering. 

mpls ldp advertise-labels for 10 (where 10 is an access list)

 

Another issue is that while the router was rebooting, it caused a significant interruption to other routers on the network.  I know I haven't supplied much detail about this as there isn't much to supply, however, it seems to relate to the error message I received above - or perhaps it's a result of the mpls network under significant load while learning the prefixes from the router that just reloaded.  Would MPLS Graceful restart assist here?

Many thanks,

Jonathan.

2 Replies 2

Renan Abreu
Cisco Employee
Cisco Employee
Did the router generate a crash info file? It sounds odd to me a crash because of a dup addr.

Hi Renan,

I don't think the crashed was caused by the dup addr - in fact I'd be very surprised if did.

The problem came when the router was restarting - that's when I saw the dup addr in the router's log and the rest of the network paused while this was going on.

Thanks,

Jonathan

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