RE: BGP Aggregate Summary only posted 04/13/2003
If you use the summary-only on the aggregate command, more specific routes
are suppressed whether they are redistributed or the network command is
From: nobody@xxxxxxxxxxxxxx [mailto:nobody@xxxxxxxxxxxxxx]On Behalf Of
Sent: Sunday, April 13, 2003 12:39 PM
Subject: BGP Aggregate Summary only
I've been doing Fatkid's Lab #505 and I've seen a strange behaviour on the
aggregate address, based on what Cisco says. The topology is very simple :
R1 [AS300] connected to R2 [AS200] and R5 [AS200], R2 and R5 are in confed
with local AS 10060. R1 has four loopbacks (184.108.40.206, 220.127.116.11,
18.104.22.168, 22.214.171.124) injected in BGP via network commands. The
requirement is to just send the aggregate 126.96.36.199/16. And I'm using the
"aggregate 188.8.131.52 255.255.0.0 summary-only".
In case #4 in
9186a00800c95bb.shtml, it says :
"Please note that if we are aggregating a network that is injected into our
BGP via the network statement (ex: network 184.108.40.206 on RTB) then the
network entry is always injected into BGP updates even though we are using
"the aggregate summary-only" command. The upcoming CIDR example discusses
this situation.", where it basically talks about redistributing statics
instead of using "network".
So according to Cisco, this should NOT work ! BUT it does !!! : R2 & R5
don't have the subnets and only have the summary. And "sh ip bgp" on R1
shows the 4 subnets as "s>", ie. suppressed.
Is the doc wrong ?