From: Mark Lewis (markl11@xxxxxxxxxxx)
Date: Mon Oct 02 2000 - 14:49:15 GMT-3
Hi,
The 'auto-summary' command is relevant for routes injected into BGP using
the 'redistribute' command (rather than the 'network' command).
If you for example configure 3xstatic routes to 87.1.1.0,87.2.1.0, and
87.3.1.0 and used the 'redistribute' command to inject them into BGP, you'll
notice that BGP auto-summarizes them to 87.0.0.0. Use 'no auto-summary' to
turn this off & get your specific routes (by the way, in the doc.s it say
this feature is for IGP routes only, but as you'll see if you configure the
above, it works for statics too).
Hope that helps,
Mark
>From: "Connary, Julie Ann" <jconnary@cisco.com>
>Reply-To: "Connary, Julie Ann" <jconnary@cisco.com>
>To: ccielab@groupstudy.com
>Subject: bgp auto-summary
>Date: Mon, 02 Oct 2000 11:42:10 -0400
>
> Hi all,
>
> I am trying to understand BGP and auto-summary.Halabi's book on page 34
4
>shows how to put
>in an aggregate-address to summarize and suppress more specific routes:
>
>router bgp 3
> no synchronization
> network 172.16.1.0 mask 255.255.255.0
> network 172.16.10.0 mask 255.255.255.0
> network 172.16.65.0 mask 255.255.255.192
> network 172.16.220.0 mask 255.255.255.0
> aggregate-address 172.16.0.0 255.255.0.0 summry-only
> neighbor 172.16.1.2 remote-as 3
> neighbor 172.16.20.1 remote-as 1
> neighbor 172.16.20.1 filter-list 10 out
> no auto-summary
>
>ip as-path access-list 10 permit ^$
>
>
>So I tried this, worked great. Then Halabi says that the same result could
>be achieved using auto-summary.
>I removed the aggregate-address statement and then issued an "auto-summary"
>command.
>I cleared the bgp tables, but my neighbor in AS 1 still gets all the
>specific subnets vs. a summary route.
>
>Anyone know why?
>
>My OS version is 11.3(11a)
>
>Thanks,
>
>Julie Ann
>
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