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Forum Replies

  1. @ReneMolenaar @lagapides have a question concerning the filter-list filtering. This may sound like a silly question. Why did you do the configurations to add AS 11 to the AS path out going 2001:db8:0:1::/64 traffic on R1. Why didn’t you do it on router R2?.

    R1(config)#router bgp 1
    R1(config-router)#address-family ipv6
    R1(config-router-af)#neighbor 2001:db8:0:12::2 route-map PREPEND out

    Since we are using the neighbor command. Shouldn’t the command be affecting the neighbor router and not the local router. Please, i need clarification.

  2. Hello Mayowa

    The PREPEND command will add AS 11 to the AS path when R1 advertises the specific route to R2. So if R1 tells R2 that the path to the destination is through AS1 and AS11, then these two ASs will be added to the BGP table of R2 which is what we want to do.

    I hope this has been helpful!


  3. @lagapides I understand. I am just a little bit confuse because when you use the neighbor command, it is most time used to configure things on neighbor router. But in this case, it is used to configure AS-PATH on the local Router (R1). What if instead of doing:
    R1(config)#neighbor 2001:db8:0:12::2 route-map PREPEND out

    i do the configurations from R2. I configure the ipv6 prefix-list and route-map on R2 and then use the command;
    R2(config)#neighbor 2001:db8:0:12::1 route-map PREPEND out

    Will this also work?.

  4. Hello Mayowa

    I understand your confusion. When you implement the neighbor command, it is used to create the neighbor relationship. It is also used to configure parameters that pertain to the relationship. But it is never used to configure anything on the neighboring router. Whenever a route map is used in a network command, it always filters the advertisements on that relationship. The in or out keywords indicate which direction is filtered.

    Now if you were to implement the command you state above, it would enable filtering for the advertisement of routes

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