[59499] in North American Network Operators' Group
RE: Newbie network upgrade question, apologies in advance to NANOG
daemon@ATHENA.MIT.EDU (Vandy Hamidi)
Wed Jul 2 16:36:34 2003
Date: Wed, 2 Jul 2003 13:35:57 -0700
From: "Vandy Hamidi" <vandy.hamidi@markettools.com>
To: "prue" <prue@usc.edu>
Cc: <nanog@merit.edu>
Errors-To: owner-nanog-outgoing@merit.edu
I would agree only under certain limited situations.
Per packet load balancing COULD increase jitter, and if you're running =
VOIP (or similar protocols) could degrade performance. It could also =
affect TCP performance (on OSes not SACK enabled) as well.
This would only really happen if you're T1's are near capacity (~above =
80% or so). Near when queues start causing noticeable delays.
If were talking about 2 identically configured T1's, on the same router, =
through the same loop provider, connected to one ISP--I highly doubt a =
situation where packet reordering would arise. It's not impossible, but =
unlikely as all the circuits would be utilized the same, thus queue =
delays should be similar across the board.
I've done this on a private network with 4 T1's and never had a problem. =
We were pushing 100GB database dumps across it and performance did =
quadruple over the single T1.
-=3DVandy=3D-
-----Original Message-----
From: prue [mailto:prue@usc.edu]
Sent: Wednesday, July 02, 2003 1:21 PM
To: Vandy Hamidi
Cc: nanog@merit.edu
Subject: RE: Newbie network upgrade question, apologies in advance to
NANOG
Vandy,
>Also, you may want to set your border router (the one with the serials =
to your=20
>ISP) to route "per packet" as opposed to allowing the routes to cache. =
This=20
>will distribute the bandwidtch evenly across your T1's. If you don't, =
then a=20
>single high traffic session or destination can consume an uneven amount =
of=20
>bandwidth on one of your lines. You can ask your ISP to do this as =
well for=20
>incoming packets.
That is not such a good idea generally. If you do this then you get =
packet=20
reordering. This can be detrimental to TCP performance.
Walt
