VRF Lite with dial backup connection

Unanswered Question
Jul 2nd, 2008
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Hi Guys,

We have a WAN router which will be used by two different company (previously only one). So to separate the traffic we want to implement the VRF Lite in our WAN Router as we will have two L3 connection to the Provider. We have an isdn backup connection to the PE router in case the connection to the provider is down. The main concern is that when the connection to the provider is down, how can I route 2 vrf traffic in one L3 connection? Let say if the ISDN Connection is in VRF A, how can I route the VRF B traffic though the same link? We use static route.

Any comment will be appreciated.



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royalblues Thu, 07/03/2008 - 01:19
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Do not configure the ISDN interface to be a part of any VRF.

Then i think you can configure floating static routes pointing to the ISDN interface as backup.


mlund Fri, 07/04/2008 - 02:56
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I did this a couple years ago. I however don't have the exact config, but the idea is, make the bri a layer2 and configure 2 dialer-interfaces for layer3. Something like this

int bri0

dialer pool-member 1

dialer pool-member 1 max-link 1

dialer pool-member 2

dialer pool-member 2 max-link 1

int dialer 1

ip vrf forwarding custA

dialer pool 1

int dialer 2

ip vrf forwarding custB

dialer pool 2

more info on dialer pool config here




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