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Forcing a route through an alternate interface

Hello, I have a 3600 series router with an ethernet interface and two serial interfaces. Each serial interface connects to a separate ISP. The ISPs are sending us full routes via BGP, but for whatever reason there are issues balancing the load. We would like to force traffic leaving the router destined to a certain network out of a specific interface. By default it is passing the traffic to neighbor AS XXX (AS associated with ISP A). I have tried a couple different routes to chage the behavior. One, I tried a static route to the AS XXXX of ISP B. It goes there but immediately after the first hop it uses AS paths of ISP A. Then I just tried a static route with the interface name of serial0/1 (ISP B serial). Still it takes the default AS path of ISP A. Aside from routes being cached are there other configuration detail to be aware of when trying this?



Re: Forcing a route through an alternate interface

Policy routing can be used to force particular traffic over particular interfaces.

See the following URL for an example -

New Member

Re: Forcing a route through an alternate interface

Ok. Here is my config related to policy routing. The interface I want the traffic to leave is Serial0/0. I replaced the IP's with X's, they are valid IP addresses / networks. I do not fully understand what I read, but think I have a basic idea. Its not working though. Still takes AS of ISP A.


interface Serial0/0

ip address X.X.X.X

encapsulation frame-relay IETF

no ip mroute-cache

ip policy route-map net-XX.XX.XXX

no fair-queue

service-module t1 timeslots 1-24

service-module t1 remote-alarm-enable

frame-relay map ip X.X.X.X 16 broadcast IETF

frame-relay lmi-type ansi


access-list 111 permit ip X.0.0.0 any


route-map net-XX.XX.XXX permit 10

match ip address 111

set interface Serial0/0


route-map net-XX.XX.XXX permit 20

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