RE: Newbie network upgrade question, apologies in advance to NANOG
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. -=Vandy=- -----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 ISP) to route "per packet" as opposed to allowing the routes to cache. This will distribute the bandwidtch evenly across your T1's. If you don't, then a single high traffic session or destination can consume an uneven amount of bandwidth on one of your lines. You can ask your ISP to do this as well for incoming packets.
That is not such a good idea generally. If you do this then you get packet reordering. This can be detrimental to TCP performance. Walt
On Wed, 2 Jul 2003, Vandy Hamidi wrote:
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.
Yes, but the original poster was dealing with DS3s connected to different NAPs, which is why the packet out-of-order issue can be significant. Andy --- Andy Dills Xecunet, Inc. www.xecu.net 301-682-9972 ---
Andy Dills wrote:
Yes, but the original poster was dealing with DS3s connected to different NAPs, which is why the packet out-of-order issue can be significant.
I'd say that a more significant issue is customer throughput. The nice aspect of per conn is that it not only tends to keep a decent load balance, it also limits bandwidth hogs from saturating all circuits. This of course depends on your desired result. An example in my case is my helpdesk. They are off two t1's with dsl and dialup customers. I'd prefer them not to tank both t1's when transfering files to and from the core servers. -Jack
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Vandy Hamidi