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Forum Replies

  1. Hi Derek,
    There are three cases that must be considered for your question. I will answer your question directly first, and then mention the other two cases.

    Case #1:
    Think of “default-information originate” as a safety check. Suppose there was some careless BGP admin that told a router to redistribute some other protocol’s routes into BGP, say EIGRP. If that admin didn’t use a route-map or some other filter, and he didn’t think about that EIGRP was advertising a default route, the consequences could be really bad. You might not want all of your BGP peers to

    ... Continue reading in our forum

  2. Hi Rouzbeh,

    1. If no mask is specified, default mask is used, that is /8 in your example.
    2. When Rene said “exact mask has to be added in network command” meant that if we have a prefix in routing table (say, and we want this prefix to be injected in bgp with network command we should use
    router bgp 1

    in our config.
    If we are going to use:

    router bgp 1

    , router will assume an implicit mask (
    So prefix will not enter bgp table because we do not have

    ... Continue reading in our forum

  3. Hello Mohammad

    BGP does use triggered updates when it learns of a change on its internal domain. However, there are a few things that affect the operation of this triggering that will in turn affect the behaviour of BGP.

    Lets say that there is a network on the internal domain that is learned via OSPF, and this network continually goes up and down. BGP updates will be affected by the following:

    1. The detection of the changes - how fast does the router detect that the OSPF route is down? This depends primarily on the BGP scanner process. This process walks th

    ... Continue reading in our forum

  4. Hello Hussein,

    That is no problem. You advertise the network with the network command and then use route-maps to filter what you need.

    Here’s R1 advertising to R2:

    R1#show ip bgp neighbors advertised-routes 
    BGP table version is 4, local router ID is
    Status codes: s suppressed, d damped, h history, * valid, > best, i - internal, 
                  r RIB-failure, S Stale, m multipath, b backup-path, f RT-Filter, 
                  x best-external, a additional-path, c RIB-compressed, 
                  t secondary path, 
    Origin codes: i - IGP, e - EGP, 
    ... Continue reading in our forum

  5. Hello Hussein,

    I’m afraid you can’t do this. With BGP, the network command adds something to the global BGP table and then you can use route-maps to decide if you want to advertise something or not to your neighbors.

    What exactly are you trying to do? If you want something where you don’t advertise anything to a neighbor unless you configure it to do so, then you still could use a route-map with some regular expressions. For example, let’s say you don’t want to advertise anything by default that you added to the BGP table then you can use a route-map with a reg

    ... Continue reading in our forum

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