From: Ouellette, Tim (tim.ouellette@eds.com)
Date: Mon Dec 23 2002 - 22:45:24 GMT-3
Jeremy,
Let's break this down.
Case #1
The router is going to adverise the 192.168.32.0 /21 route and supress the
more specific routes of that network because you have the summary-only
keyword added. So the more specifics with show supressed in your "sh ip
bgp". Then you have an unsupress-map pointing to your neighbor which match
ACL 1 which says 192.168.36.0 and any networks that fall into that class C
will be unsupressed to that neighbor.
Outcome : 192.168.32.0/21 and 192.168.36.0 will be advertised but anything
such as 192.168.33.0/34.0/35.0/37.0/38.0 will be supressed and therefor not
advertised.
Case #2
Your creating the same 192.168.32.0 /21 aggregate but not using the
summary-only keyword so none of the more specifics are being supressed at
this time and would normally get advertised to the neighbor. But, you have a
supress map being applied to the neighbor so anything matching the
192.168.36.0/x will be supressed to that neighbor.
Outcome: 192.168.32.0/21 will be advertised as well all the more specifics
EXCEPT 192.168.36.0/x
So to answer the question, No, I don't think they are the same. They both
advertise the 192.168.32.0/21 but the first one allows the more specific
192.168.36.0 to be advertised whereas the 2nd example denies that one but
allows the rest.
Close but not quite the same.
HTH
Tim
-----Original Message-----
From: Wright, Jeremy [mailto:JA_WRIGHT@admworld.com]
Sent: Monday, December 23, 2002 2:08 PM
To: 'ccielab@groupstudy.com'
Subject: bgp aggregate suppress question
are these basically accomplishing the same thing (except one is going to a
particular neighbor)?
aggregate address 192.168.32.0 255.255.248.0 summary-only
access-list 1 permit 192.168.36.0
route-map not36 permit 10
match ip address 1
neighbor x.x.x.x unsuppress-map not36
OR:::
aggregate address 192.168.32.0 255.255.248.0 suppress-map not36
access-list 1 permit 192.168.36.0
route-map not36 deny 10
match ip address 1
route-map not36 permit 20
.
.
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