Avoiding a Transit Provider

Discussion in 'Cisco' started by Gary, Feb 4, 2004.

  1. Gary

    Gary Guest

    We take transit from 2 suppliers and one of our transit customers does not
    like one of the upstreams we use.

    i.e

    Customer uses us and we use upstream A and B

    Is there a way to stop our customers IP Allocation (/19) from RIPE using say
    upstream B and sending all their traffic via upstream A

    We provide transit to their AS using BGP.

    Gary
     
    Gary, Feb 4, 2004
    #1
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  2. Gary

    Ivan Ostres Guest

    Just stop announcing their addr.block trough unwanted provider.
     
    Ivan Ostres, Feb 4, 2004
    #2
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  3. That will stop the inbound traffic from using that provider. For the
    outbound traffic, he'll need to use policy routing on his border router
    to force everything through A whenever the source address is in this /19.
     
    Barry Margolin, Feb 4, 2004
    #3
  4. Gary

    timo Guest

    Hey

    I enabled some real simple policy routing (route-map,match acl, set ip
    next hop)on a few of my 3640's the other day and right after the CPU
    was pinned. I was only sending about 3-4Mb of traffic through... Is
    this typical ? Ive heard the 3640 does this in software , do the
    bigger routers also do PBR in software??

    Thanks for any info..

    Tim
     
    timo, Feb 5, 2004
    #4
  5. What software version are you running? Is CEF enabled? The 3600
    series routes all packets in software so that in of itself isn't the
    issue here -- what matters is the switching path that the
    policy-routed packets are taking. Policy routing has been CEF-capable
    since 12.0, and uses CEF automatically if CEF is enabled globally.
    The performance hit that you're seeing indicates that the
    policy-routed packets probably aren't being CEF'd for some reason.

    -Terry
     
    Terry Baranski, Feb 5, 2004
    #5
  6. Gary

    Gary Guest


    Please could I have a basic command set to do that.

    Gary
     
    Gary, Feb 5, 2004
    #6
  7. Gary

    Ivan Ostres Guest

    This would be a sample:

    access-list 5 permit ip customer_network customer_netmask

    route-map customer_x permit 10
    match ip address 5
    set interface outgoing_interface_to_wanted_provider

    route-map customer_x permit 20


    int incoming_interface_from_customer
    ....
    ip policy route-map customer_x


    This is just from my head and that can sometimes be wrong :). But
    that's the idea.

    The thing that is bothering me all the time is that you are provider to
    someone and you have to deal with BGP & stuff with such low knowledge of
    internet routing that you're unable to solve such simple problem or to
    find out how to mahe route-map using docs on cisco site.

    Is it just me or....?
     
    Ivan Ostres, Feb 5, 2004
    #7
  8. Gary

    timo Guest

    DOH!!! CEF is not enabled and Im running 12.3.3.... Ill enable it and
    try my route-maps again.

    On to a defaults question now... Why is CEF not enabled by default, in
    most cases CEF is prety darn good for the router isnt it?? I know
    that I have had to 'ip cef' to enable it on several of my OTHER
    routers...

    Thanks Much

    Tim
     
    timo, Feb 5, 2004
    #8
  9. Cisco is generally reluctant to change defaults in IOS, and with good
    reason -- when upgrading IOS you don't want to have to worry about
    what defaults have changed that are going to break your configuration.
    Some changes are inevitable, but the less common they are, the better.

    -Terry
     
    Terry Baranski, Feb 6, 2004
    #9
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