Adding a BGP advertisement

Discussion in 'Cisco' started by essenz, Jan 31, 2008.

  1. essenz

    essenz Guest

    This may seem like a trivial question, but the last time I tried it,
    it didn't work.

    I only have a small window to test, so wanted to see if I am doing
    everything correctly.

    I have two routers, each with a separate /22 IP range on them being
    advertised out.

    One router will be shutdown in the next few weeks, so I am going to
    move that /22. They way I am moving it is to move each /24 by itself
    over to the new router.

    Global routing will go to the new router since the /24 advertisement
    over there is more specific.

    So all I have to do is add the /24 advertisement on the new router.

    I tried this last night, but it didn't seem to take.

    Basically, I went into my "router bgp XYZ" config, and added the line:

    network A.B.C.D mask 255.255.255.0

    Then I did:

    clear ip bgp X.X.X.X soft (where X.X.X.X is my upstream neighbor)

    After doing that, I couldn't verify that the /24 was being advertised:

    sh ip bgp neighbors X.X.X.X advertised-routes

    And it only showed my existing /22, not the new /24 I just added.

    I called the carrier and confirmed that they will allow the /24
    advertisement.

    Any ideas?
    essenz, Jan 31, 2008
    #1
    1. Advertising

  2. essenz

    Trendkill Guest

    On Jan 31, 11:40 am, essenz <> wrote:
    > This may seem like a trivial question, but the last time I tried it,
    > it didn't work.
    >
    > I only have a small window to test, so wanted to see if I am doing
    > everything correctly.
    >
    > I have two routers, each with a separate /22 IP range on them being
    > advertised out.
    >
    > One router will be shutdown in the next few weeks, so I am going to
    > move that /22. They way I am moving it is to move each /24 by itself
    > over to the new router.
    >
    > Global routing will go to the new router since the /24 advertisement
    > over there is more specific.
    >
    > So all I have to do is add the /24 advertisement on the new router.
    >
    > I tried this last night, but it didn't seem to take.
    >
    > Basically, I went into my "router bgp XYZ" config, and added the line:
    >
    > network A.B.C.D mask 255.255.255.0
    >
    > Then I did:
    >
    > clear ip bgp X.X.X.X soft (where X.X.X.X is my upstream neighbor)
    >
    > After doing that, I couldn't verify that the /24 was being advertised:
    >
    > sh ip bgp neighbors X.X.X.X advertised-routes
    >
    > And it only showed my existing /22, not the new /24 I just added.
    >
    > I called the carrier and confirmed that they will allow the /24
    > advertisement.
    >
    > Any ideas?


    Please post your entire bgp config, and any relevant route-maps.
    Trendkill, Jan 31, 2008
    #2
    1. Advertising

  3. essenz

    essenz Guest

    On Jan 31, 11:46 am, Trendkill <> wrote:
    > On Jan 31, 11:40 am, essenz <> wrote:
    >
    >
    >
    > > This may seem like a trivial question, but the last time I tried it,
    > > it didn't work.

    >
    > > I only have a small window to test, so wanted to see if I am doing
    > > everything correctly.

    >
    > > I have two routers, each with a separate /22 IP range on them being
    > > advertised out.

    >
    > > One router will be shutdown in the next few weeks, so I am going to
    > > move that /22. They way I am moving it is to move each /24 by itself
    > > over to the new router.

    >
    > > Global routing will go to the new router since the /24 advertisement
    > > over there is more specific.

    >
    > > So all I have to do is add the /24 advertisement on the new router.

    >
    > > I tried this last night, but it didn't seem to take.

    >
    > > Basically, I went into my "router bgp XYZ" config, and added the line:

    >
    > > network A.B.C.D mask 255.255.255.0

    >
    > > Then I did:

    >
    > > clear ip bgp X.X.X.X soft (where X.X.X.X is my upstream neighbor)

    >
    > > After doing that, I couldn't verify that the /24 was being advertised:

    >
    > > sh ip bgp neighbors X.X.X.X advertised-routes

    >
    > > And it only showed my existing /22, not the new /24 I just added.

    >
    > > I called the carrier and confirmed that they will allow the /24
    > > advertisement.

    >
    > > Any ideas?

    >
    > Please post your entire bgp config, and any relevant route-maps.


    I think I figured it out. I forget to add a null route for that /24 -
    so thats why it wasn't being advertised out.
    essenz, Jan 31, 2008
    #3
  4. essenz

    Trendkill Guest

    On Jan 31, 11:54 am, essenz <> wrote:
    > On Jan 31, 11:46 am, Trendkill <> wrote:
    >
    >
    >
    > > On Jan 31, 11:40 am, essenz <> wrote:

    >
    > > > This may seem like a trivial question, but the last time I tried it,
    > > > it didn't work.

    >
    > > > I only have a small window to test, so wanted to see if I am doing
    > > > everything correctly.

    >
    > > > I have two routers, each with a separate /22 IP range on them being
    > > > advertised out.

    >
    > > > One router will be shutdown in the next few weeks, so I am going to
    > > > move that /22. They way I am moving it is to move each /24 by itself
    > > > over to the new router.

    >
    > > > Global routing will go to the new router since the /24 advertisement
    > > > over there is more specific.

    >
    > > > So all I have to do is add the /24 advertisement on the new router.

    >
    > > > I tried this last night, but it didn't seem to take.

    >
    > > > Basically, I went into my "router bgp XYZ" config, and added the line:

    >
    > > > network A.B.C.D mask 255.255.255.0

    >
    > > > Then I did:

    >
    > > > clear ip bgp X.X.X.X soft (where X.X.X.X is my upstream neighbor)

    >
    > > > After doing that, I couldn't verify that the /24 was being advertised:

    >
    > > > sh ip bgp neighbors X.X.X.X advertised-routes

    >
    > > > And it only showed my existing /22, not the new /24 I just added.

    >
    > > > I called the carrier and confirmed that they will allow the /24
    > > > advertisement.

    >
    > > > Any ideas?

    >
    > > Please post your entire bgp config, and any relevant route-maps.

    >
    > I think I figured it out. I forget to add a null route for that /24 -
    > so thats why it wasn't being advertised out.


    You shouldn't need that if the /24 is in the routers IGP (ie ospf,
    eigrp, rip). Also depends if synchronization is on or not.
    Trendkill, Jan 31, 2008
    #4
    1. Advertising

Want to reply to this thread or ask your own question?

It takes just 2 minutes to sign up (and it's free!). Just click the sign up button to choose a username and then you can ask your own questions on the forum.
Similar Threads
  1. Ivan Ostres

    BGP conditional advertisement

    Ivan Ostres, Aug 2, 2004, in forum: Cisco
    Replies:
    8
    Views:
    4,973
    Ivan Ostres
    Aug 9, 2004
  2. harald rüger
    Replies:
    0
    Views:
    531
    harald rüger
    Oct 25, 2004
  3. Garry
    Replies:
    6
    Views:
    851
    Cisco Fan
    Mar 21, 2005
  4. Replies:
    0
    Views:
    539
  5. qamar

    BGP Conditional advertisement with Community attributes

    qamar, Sep 15, 2009, in forum: General Computer Support
    Replies:
    0
    Views:
    1,553
    qamar
    Sep 15, 2009
Loading...

Share This Page