On Jan 14, 2008 10:30 AM, Drew Weaver <drew.weaver@thenap.com> wrote:
I haven't noticed too many instances of this causing huge performance problems, but I have noticed some, has anyone noticed any instances in the real world where this has actually caused performance gains over symmetrical routing?
Drew, There are at least two common scenarios where intentional asymmetric routing (aka traffic engineering) benefits the sender: Scenario 1: InterNAP-like product where the outbound packet takes a path optimized for conditions other than shortest AS path. Conditions might include minimize packet loss or maximize throughput as determined by ongoing communication with testpoints in that direction. Scenario 2: Cost minimization for bulk transfer. If you operate a large mailing list or a usenet server, you might arrange for traffic from the server to prefer peers first and then your lowest-cost transit provider. Regards, Bill Herrin -- William D. Herrin herrin@dirtside.com bill@herrin.us 3005 Crane Dr. Web: <http://bill.herrin.us/> Falls Church, VA 22042-3004