Re: bgp route advertisment , particularly aggregate/summary to

Maybe this will help:

R1(config-router)#do sh ip int b
Interface IP-Address OK? Method Status
 Protocol
Serial0/1 10.1.12.1 YES manual up
 up
Loopback1 172.16.1.1 YES manual up
 up
Loopback2 172.16.2.1 YES manual up
 up
Loopback3 172.16.3.1 YES manual up
 up

R1(config-router)#do sh run | s bgp
router bgp 1
 no synchronization
 bgp log-neighbor-changes
 network 172.16.1.0 mask 255.255.255.0
 network 172.16.2.0 mask 255.255.255.0
 network 172.16.3.0 mask 255.255.255.0
 neighbor 10.1.12.2 remote-as 1
 no auto-summary

!!!

*R2*(config)#do sh run | s bgp
router bgp 1
 no synchronization
 bgp log-neighbor-changes
 neighbor 10.1.12.1 remote-as 1
 no auto-summary

R2(config)#do sh ip bgp
BGP table version is 10, local router ID is 2.2.2.2
Status codes: s suppressed, d damped, h history, * valid, > best, i -
internal,
              r RIB-failure, S Stale
Origin codes: i - IGP, e - EGP, ? - incomplete

   Network Next Hop Metric LocPrf Weight Path
*>i172.16.1.0/24 10.1.12.1 0 100 0 i
*>i172.16.2.0/24 10.1.12.1 0 100 0 i
*>i172.16.3.0/24 10.1.12.1 0 100 0 i

!!!

<Create an aggregate>

R1(config)#router bgp 1
R1(config-router)#aggregate-address 172.0.0.0 255.0.0.0 summary-only

!!!

R2(config)#do sh ip bgp
BGP table version is 14, local router ID is 2.2.2.2
Status codes: s suppressed, d damped, h history, * valid, > best, i -
internal,
              r RIB-failure, S Stale
Origin codes: i - IGP, e - EGP, ? - incomplete

   Network Next Hop Metric LocPrf Weight Path
*>i172.0.0.0/8 10.1.12.1 0 100 0 i

!!!

I hope this is helpful!

On Sat, Mar 10, 2012 at 12:58 PM, Aaron <aaron1_at_gvtc.com> wrote:

> In a recent scenario I was using for my studies I was presented with the
> following..Please tell me how to do the following or link to where it is on
> doc cd.
>
>
>
> If R1 has in its igp table.
>
>
>
> 172.16.1.0/24
>
> 172.16.2.0/24
>
> 172.16.3.0/24
>
>
>
> And you need to send an aggregate of that as 172.0.0.0/8 to a IBGP
> neighbor
> how would you accomplish that? I don't think a static route is
> permissible.
> I don't think you can create additional interfaces on r1 either.
>
>
>
> If you can just verbalize to me a few ideas of how that is accomplished
> without some elaborate config then that's fine.like what are the moving
> parts?
>
>
>
> Is it possible to generate an aggregate based solely on the contents of the
> IGP table? I think I read that a subordinate part of a larger aggregate
> needs to be present in the igp table in order for the aggregate to be sent,
> but do I use "aggregate-address" ?....suppresmap? unsurprssmap? .neighbor
> statement to that certain neighbor?
>
>
>
> Aaron
>
>
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>
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Received on Sat Mar 10 2012 - 14:19:34 ART