mailing list archives
Re: BGP community based IP filtering
From: Alan Hannan <hannan () bythetrees com>
Date: Thu, 15 Jan 1998 11:26:40 -0500
I've been having an email discussion with a couple of Cisco engineers about
how useful BGP community based IP filtering might be. The following IOS
config fragment might help explain what I'm getting at:
ip access-group community-list 10 in
ip community-list 10 permit AA:BB
ip community-list 10 permit CC:DD
If you are using communities to make your prefix announcements to peers,
this then allows the router to filter incoming IP packets that match your
announcements. Excepting things like CPU load, implementation details, etc
do you think this would be helpful, or am I way off with this?
I think this would be helpful; especially if were scaled as a
ubiquitous implementation mechanism.
Further implementations of BGP community based decision criteria
could include Class of Service/Type of Service Priority Setting; based
upon a particular community, give packets with this network
source/destination X priority.
Additionally, other services such as selective NAT (do or do not
NAT based upon communities, NAT into which address space based
upon communities), etc... can be implemented.
Similar to the regexp niftiness being put into access lists, it'd
be keen to see all features using ACLs accept communities as
Bear in mind this is not terribly useful to the world if Cisco
does it alone, it should be tracked through IETF, but it would be
nice if Cisco did the proof-of-concept and led the pack.
Re: BGP community based IP filtering Mark Prior (Jan 16)