[30660] in North American Network Operators' Group
Community NO-EXPORT
daemon@ATHENA.MIT.EDU (Dave Cahill)
Tue Aug 22 11:14:27 2000
Message-ID: <1AAE1D2D1003D311882400902771AA470112E9F1@mail.salesforce.com>
From: Dave Cahill <dcahill@salesforce.com>
To: "'nanog@merit.edu'" <nanog@merit.edu>
Date: Tue, 22 Aug 2000 08:12:34 -0700
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Errors-To: owner-nanog-outgoing@merit.edu
Community NO-EXPORT
I have AS1 connected to AS2 via two different paths and different routers
|-------------------| |--------|
| |---------| |-----OTHERS
| AS1 | | AS2 |
| 192.168.0.0/16 | | |
| |---------| |-----OTHERS
|-------------------| |--------|
I advertise my class B range from AS1 for example 192.168.0.0/16 on both
routers but
to achieve some load-sharing I addvertise 192.168.0.0/17 on one router and
192.168.128.0/17 on the other router as well.
I setup a community NO-EXPORT for the /17 so AS2 won't advertise them out to
other AS's.
The question
In AS2 BGP selects the best route and /17 should be selected because of the
longest
match rule. BGP places the /17 in its routing table. BGP should only
UPDATE the other
IBGP Peers with its routing table entry (IE Each router won't send it's
entire BGP database).
So if the /17 will be sent to other IBGP with the community NO-EXPORT how do
other AS's learn
about the /16 ?
Dave Cahill
