North American Network Operators Group
Date Prev | Date Next | Date Index | Thread Index | Author Index | Historical

Re: FW: BGP Load Sharing

  • From: Chris Strandt
  • Date: Sat Sep 18 09:59:57 2004

This is effectivly what we are doing today, on a slightly more sofisticated level.

We produce a report based on netflow statistics that tells us (in percentage terms) which asn's we are sending traffic to. We then look at our current BGP table, which we get from SNMP. We take the asn's which recieve 60% of our traffic.. and make a few descisions.

1) If as path length is shorter via one provider over the other, make sure we prefer the shorter path.
2) If they are equal length, split the list of asn's between the 2 providers based on the input of the script.

So back to the question at hand... to get netflow stats for outgoing traffic.. we need cards in the 12K router which will support netflow on the ingress ports of the router for outgoing traffic(ie Gigabit Ethernet Line Cards)... right?

-Chris





Mike McSpedon wrote:

What you advertise to upstreams affects incoming traffic, not outgoing.


What upstreams advertise to you and the policies you employ on those routes
affects outgoing. One basic technique is to decide roughly how much outgoing
traffic you want going over each link, then look at how your current
outgoing traffic is split (e.g., 70% via ISPA, 30% via ISPB) then manipulate
the Local Preference attribute on some of the routes you're receiving to
achieve roughly the balance you're looking for.


Mike McSpedon
Arrow Global Data Communications
Arrow Electronics, Inc.
50 Marcus Drive
Melville, New York 11747
Phone: 631.847.5551