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isdn backup

Hi

I have a question about isdn backup configurations. when use floating static route, by redistribution of static route in to dynamic routing protocol, other routers can send packet to isdn link after primary link down. when use backup interface command, how can other routers send traffic to isdn link after primary link down?

3 REPLIES

Re: isdn backup

Hi

AFAIK if you have different primary links connected to different locations backed up with isdn line then you may need to configure or identify the exact backup interface or the isdn line which has to trigger in case of some failure with the primary line.

But the floating static route is required without which the packets maynot know which path it has to take to reach the destination network.

regds

VIP Purple

Re: isdn backup

Hello,

here is an example of how the process works:

interface Serial0

backup interface BRI0

!

ip route 0.0.0.0 0.0.0.0 BRI0 200

The backup interface command just checks the availability of the primary interface, if that interface is down, the backup interface (BRI0 in this case) is brought up, but the traffic still needs to be routed out the interface, that is what you need the floating static route for...

Does that make sense ?

Regards,

GP

New Member

Re: isdn backup

Hi

thanks for answering.

if still need the static route, why use "backup interface" conmmand, its unnecessary at all. without backup interface command, which means with only floating static route, it works fine.

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