Re: Poor Performance for ethernet bonding

From: Thomas Davis (tadavis@lbl.gov)
Date: Fri Aug 24 2001 - 13:17:42 EST


Ben Greear wrote:
>
> Couldn't the bonding code be made to distribute pkts to one interface or
> another based on a hash of the sending IP port or something? Seems like that
> would fix the reordering problem for IP packets.... It wouldn't help for
> a single stream, but I'm guessing the real world problem involves many streams,
> which on average should hash such that the load is balanced...
>

Cisco etherchannel does this, by XOR'ing the dest address with the
source address, AND'ing with # of interfaces (limiting you to a power of
2), and then using the number to determine what channel to use.

Now, you end up in a 4 way Etherchannel, all the traffic going down one
channel, and the none going down the other three. Does that sound like
a balanced solution?

Most bonding problems are either the card driver is busted, the card is
busted (el-cheapo NE2000 PCI clones are really bad..) or the switch
can't handle it. Most cheap, dumb switches break big time when using
Bonding with them.

-- 
------------------------+--------------------------------------------------
Thomas Davis		| ASG Cluster guy
tadavis@lbl.gov		| 
(510) 486-4524		| "80 nodes and chugging Captain!"
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This archive was generated by hypermail 2b29 : Fri Aug 31 2001 - 21:00:12 EST