Redundancy Two ATM interfaces with same IP address.

[aalhousani]

Hi,

I have 7300 router with one ATM interface and configuring four PVCs, I am planning to insert 2nd ATM interface but using the same PVCs IP address of the 1st ATM.

I don't need to run any routing protocol and I have to use same ip address for both PVCs where the customer is pointing to it, also I have two RPs in the router.

[jackyoung]

Every interface in router, no matter physical or logical interface, they should assiged w/ non-duplicated IP subnet. Only if the interface is shutdown, you may able to configure it, once it is active, you can't. It is not related to the routing issue.

You may setup a loopback interface w/ the PVC original IP and assign two separated IP to two PVCs then enable the routing protocol.

But your client will require to configure the static route or default route to your PVC address.

Could you advise the reason and let's to suggest other solutions.

Hope this helps.

[aalhousani]

Thanks Jack,

I am thinking to configure a bridge for each PVCs with BVI interface, I will tryed I don't know if it will work!

[sundar.palaniappan]

Hi,

You can configure Multilink PPP over ATM, if you desire to do so, to bind the PVCs together and still be able to configure one layer 3 address (subnet) on the multilink interface.

Check out the following link,

http://www.cisco.com/en/US/products/ps6350/products_configuration_guide_chapter09186a00804a4095.html

Hope that helps!

Regards,

Sundar

[ilya.varlashkin]

To add to what Sundar said, if you have a RADIUS server nearby and you're ok with running AAL5MUX on your PVC's, then you could configure Virtual-Template interface and specify it to be used for cloning ATM sub-interface configs ('encapsulation aal5mux ppp Virtual-Template1'), after that in RADIUS profile you'll need to specify Cisco-specific AV-pair 'lcp:interface-config= '.

This way interface IP is assigned only when the line protocol on the interface is actually up.

[aalhousani]

Hello All and thanks for your respond.

I have resolved this issue by configuring bridge group... basicly I have enable bride group in the two atm interfaces and configure the ip address in the bvi interface.