BGP - Transitive / Route-Map What am I missing.

Discussion in 'Cisco' started by amyl@paxemail.com, May 23, 2005.

  1. Guest

    I am working with BGP in a lab and I am missing something that I
    clearly don't understand.

    The lab is as follows - one site (AS1234) connected to two providers
    (7018,209).

    Again this is in a lab so please do not mind the private addresses or
    any of the other fictious info I use.

    I am using the following route-map to control outbound routing updates

    access-list 10 permit 10.10.10.0 0.0.0.255
    access-list 15 permit 20.20.20.0 0.0.0.255

    !
    route-map AS-7018-OUTGOING permit 10
    match ip address 10
    set as-path prepend 12345
    !
    route-map AS-7018-OUTGOING permit 20
    match ip address 15
    set community 7018:20

    !Route map is applied...
    router bgp 12345
    neighbor 50.0.1.1 route-map AS-7018-OUTGOING out

    My understanding is that only the two IP blocks would be sent outbound
    and not the other routes learned by my IBGP neighbor. However in my
    lab when I do

    sh ip bgp nei <external peer> advertised-routes

    I see that I am advertising all of the partials I received from the
    other provider through my IBGP connection. What am I missing? I
    thought that if none of the conditions were met on the route-map that
    the route would be silently discarded and not redistributed.

    Amy.
     
    , May 23, 2005
    #1
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  2. wrote in news:1116856172.138041.101520
    @g49g2000cwa.googlegroups.com:

    > I am working with BGP in a lab and I am missing something that I
    > clearly don't understand.
    >
    > The lab is as follows - one site (AS1234) connected to two providers
    > (7018,209).
    >
    > Again this is in a lab so please do not mind the private addresses or
    > any of the other fictious info I use.
    >
    > I am using the following route-map to control outbound routing updates
    >
    > access-list 10 permit 10.10.10.0 0.0.0.255
    > access-list 15 permit 20.20.20.0 0.0.0.255
    >
    > !
    > route-map AS-7018-OUTGOING permit 10
    > match ip address 10
    > set as-path prepend 12345
    > !
    > route-map AS-7018-OUTGOING permit 20
    > match ip address 15
    > set community 7018:20
    >


    Try add the following to your route-map:

    route-map AS-7018-OUTGOING permit 30
    !

    Remember that in case the prefix you wish to export do no comply to your
    route-map, the prefix is not adverticed. Therefore you'll need a "permit
    all" in the end of your route-map.


    Cheers
    Lars Christensen
     
    Lars L. Christensen, May 23, 2005
    #2
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  3. Guest

    > Remember that in case the prefix you wish to export do no comply to
    your
    > route-map, the prefix is not adverticed. Therefore you'll need a

    "permit
    > all" in the end of your route-map.


    I may not have communicated it correctly - but I am seeing the networks
    I want to be advertised through BGP advertised to my EBGP peer. In
    addition I am seeing networks that are not matched in my route map also
    be advertised.

    Amy.
     
    , May 23, 2005
    #3
  4. Hansang Bae Guest

    wrote:

    > I am working with BGP in a lab and I am missing something that I
    > clearly don't understand.
    >
    > The lab is as follows - one site (AS1234) connected to two providers
    > (7018,209).
    >
    > Again this is in a lab so please do not mind the private addresses or
    > any of the other fictious info I use.
    >
    > I am using the following route-map to control outbound routing updates
    >
    > access-list 10 permit 10.10.10.0 0.0.0.255
    > access-list 15 permit 20.20.20.0 0.0.0.255
    >
    > !
    > route-map AS-7018-OUTGOING permit 10
    > match ip address 10
    > set as-path prepend 12345
    > !
    > route-map AS-7018-OUTGOING permit 20
    > match ip address 15
    > set community 7018:20
    >
    > !Route map is applied...
    > router bgp 12345
    > neighbor 50.0.1.1 route-map AS-7018-OUTGOING out
    >
    > My understanding is that only the two IP blocks would be sent outbound
    > and not the other routes learned by my IBGP neighbor. However in my
    > lab when I do
    >
    > sh ip bgp nei <external peer> advertised-routes
    >
    > I see that I am advertising all of the partials I received from the
    > other provider through my IBGP connection. What am I missing? I
    > thought that if none of the conditions were met on the route-map that
    > the route would be silently discarded and not redistributed.
    >


    But you're only setting the prepend, community. Are those not being
    set?

    --

    hsb


    "Somehow I imagined this experience would be more rewarding" Calvin
    **************************ROT13 MY ADDRESS*************************
    Due to the volume of email that I receive, I may not not be able to
    reply to emails sent to my account. Please post a followup instead.
    ********************************************************************
     
    Hansang Bae, May 24, 2005
    #4
  5. Guest

    I am not sure what is going on now? I went back and looked and it
    appears as if the route map is only advertising what I want it to.
    It's possible I forgot to "clear ip bgp <neighbor> soft out" to update
    what I am advertising.

    Just to be sure

    access-list 10 permit 10.10.10.0 0.0.0.255
    access-list 15 permit 20.20.20.0 0.0.0.255

    !
    route-map AS-7018-OUTGOING permit 10
    match ip address 10
    set as-path prepend 12345
    !
    route-map AS-7018-OUTGOING permit 20
    match ip address 15
    set community 7018:20

    This route map should only advertise the two networks listed in the
    above access list correct?

    Amy.,


    Hansang Bae wrote:
    > wrote:
    >
    > > I am working with BGP in a lab and I am missing something that I
    > > clearly don't understand.
    > >
    > > The lab is as follows - one site (AS1234) connected to two

    providers
    > > (7018,209).
    > >
    > > Again this is in a lab so please do not mind the private addresses

    or
    > > any of the other fictious info I use.
    > >
    > > I am using the following route-map to control outbound routing

    updates
    > >
    > > access-list 10 permit 10.10.10.0 0.0.0.255
    > > access-list 15 permit 20.20.20.0 0.0.0.255
    > >
    > > !
    > > route-map AS-7018-OUTGOING permit 10
    > > match ip address 10
    > > set as-path prepend 12345
    > > !
    > > route-map AS-7018-OUTGOING permit 20
    > > match ip address 15
    > > set community 7018:20
    > >
    > > !Route map is applied...
    > > router bgp 12345
    > > neighbor 50.0.1.1 route-map AS-7018-OUTGOING out
    > >
    > > My understanding is that only the two IP blocks would be sent

    outbound
    > > and not the other routes learned by my IBGP neighbor. However in

    my
    > > lab when I do
    > >
    > > sh ip bgp nei <external peer> advertised-routes
    > >
    > > I see that I am advertising all of the partials I received from the
    > > other provider through my IBGP connection. What am I missing? I
    > > thought that if none of the conditions were met on the route-map

    that
    > > the route would be silently discarded and not redistributed.
    > >

    >
    > But you're only setting the prepend, community. Are those not being
    > set?
    >
    > --
    >
    > hsb
    >
    >
    > "Somehow I imagined this experience would be more rewarding" Calvin
    > **************************ROT13 MY ADDRESS*************************
    > Due to the volume of email that I receive, I may not not be able to
    > reply to emails sent to my account. Please post a followup instead.
    > ********************************************************************
     
    , May 24, 2005
    #5
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