nanog mailing list archives

Re: BGP multihoming with two address spaces


From: Curtis Doty <Curtis () GreenKey net>
Date: Wed, 29 Jan 2014 08:03:37 -0800

According to telnet://route-server.twtelecom.net and
http://lookingglass.level3.net/bgp/lg_bgp_main.php BGP is working as
designed. Your single prepend on one prefix with TWTC causes a slight
preference for LVL3. Add another prepend if you want to further balance
your ingress load away from TWTC.

Or for more coarse adjustment, use the TWTC feature communities to reduce
their local preference below that of customer default (115 for TWTC). Use
4323:100 for transit default.

../C



On Wed, Jan 29, 2014 at 3:32 AM, Joseph Jenkins
<joe () breathe-underwater com>wrote:

I am seeking some feedback/help with my BGP configuration.  I am peering
with two providers level3 and tw.  Unfortunately all of my address spaces
are preferring the route over tw rather than level3.  I have tried
Prepending my AS and the carriers AS to the path on the tw side and I see
those update being accepted by internet routers, but everyone is still
preferring to install the tw routes rather than level3.  I was trying to
advertise each provider's address space out their connections and then use
the other for backup.  Now however everything is coming in through tw and
no one seems to like level3.


Thanks in advance for any guidance or assistance.

Joe




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