Policy Routing, raise OSPF Cost, or am I totally off base?

Discussion in 'Cisco' started by trbodsl, Apr 22, 2008.

  1. trbodsl

    trbodsl Guest

    Here's a small diagram of a portion of a network.

    http://dzcad90.home.mchsi.com/diagram.jpg

    The two routers depicted on the left side of the diagram are in the
    same rack in our DR datacenter. The router on the right is at our main
    datacenter. There are other connections going into both the 2611XM and
    the 7206VXR, but are not relevent to this question.

    Right now, I have OSPF routing enabled throughout the entire network,
    and all the links pictured are in the same area. All traffic from the
    main datacenter rides the 9MB MPLS pipe. The T1 from the main
    datacenter to the DR datacenter sits idle at this time and herein is
    where the problem lies.

    The DR datacenter is also one of our branches we conduct business in,
    and we have workstations on the 1.2.1.0/24 network. The servers in the
    DR Datacenter are on the 1.2.2.0/24 network. When the 9MB pipe is
    congested with SAN or IBM iSeries replication traffic, we can
    experience some slowdown on our workstations.

    I've been going over ways to get workstation traffic (1.2.1.0/24 <->
    1.1.1.0/24) to traverse the lone T1, and DR Replication traffic
    (1.2.2.0/24 <-> 1.1.1.0/24) to traverse the 9MB pipe.

    I thought of using policy routing on both the 2611 and the 7206, but
    then the 7206 would send all traffic sourced from 1.1.1.0 to the next
    hop, which would be specified as the 2611XM. I also tried increasing
    the OSPF cost on the F0/0 Ethernet Interface to 65534, thinking that
    by making this a higher cost, the T1 would then be perferred and this
    didn't work either.

    Am I on the right track or can this not be done?
     
    trbodsl, Apr 22, 2008
    #1
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  2. trbodsl

    Bod43 Guest

    Policy based routing is suitable for your requirements.
    You can match traffic against an access-list and route
    it depending on whether it matches or not. The access
    list can be any IP Standard or Extended access-list
    and so you can match source, dest, port, whatever.
    You can arrange to have the routing fall back to
    using the routing tables in the event that PBR fails.
    i.e. next hop unreachable.
     
    Bod43, Apr 23, 2008
    #2
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  3. trbodsl

    trbodsl Guest

    Wow.. I was having a major mental block.

    As soon as I tied this to an extended access list it works like a
    champ. Shutting down the T1 interface automatically falls back to the
    OSPF routing table. This is perfect.

    I was just thinking and making this too hard in my head.

    Thanks for the advice!
     
    trbodsl, Apr 23, 2008
    #3
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