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Asymmetrical routing opinions/debate
- From: Drew Weaver
- Date: Mon Jan 14 10:23:48 2008
- Accept-language: en-US
- Acceptlanguage: en-US
Pardon me if I am using the wrong term, I am using the term Asymmetrical routing to describe a scenario in which a request packet enters a network via one path and the response packet exits the network via a different path.
For example an ICMP ping request enters a network via ISP A and the reply leaves via ISP B (due to multi-homing on both networks, and or some kind of manual or automatic 'tweaking' of route preferences on one end or the other).
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? Also in a multi-homed environment is there any way to automatically limit or control the amount of Asymmetrical routing which takes place? (should you?) I have read a few papers [what few I could find] and they are conflicted about whether or not it is a real problem for performance of applications although I cannot see how it wouldn't be. Has there been any real community consensus on this issue published that I may have overlooked?
Thank you,
-Drew
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