Subject: Re: Use of 802.3ad bonding for increasing link throughput

From: Simon Farnsworth <[email-masked]>
Date: Wed, 10 Aug 2011 14:50:40 +0100

Tom Brown wrote:

> [couldn't thread with '802.3ad bonding brain damaged', as I've just
> signed up]
> 
> So, under what circumstances would a user actually use 802.3ad mode to
> "increase" link throughput, rather than just for redundancy? Are there
> any circumstances in which a single file, for example, could be
> transferred at multiple-NIC speed? The 3 hashing options are:
> 
As an example, from my server room here; I have an install server (TFTP, FTP 
and HTTP) connected by a 2x1G LACP bond to the switch. When I have multiple 
clients installing simultaneously, the layer2 hash distributes the load 
nicely across both NICs - I can reach saturation on both NICs together.

If I had routers between my clients and the install server, I'd need 
layer2+3 hashing to spread the clients over the links, but I'd still be able 
to push over a gigabit per second to the clients, despite being limited to 
1GBit/s to each individual client by the packet distribution.

I'm sure that you can think of lots of other situations in which you have 
multiple conversations sharing a link - those are the situations that gain 
speed from 802.3ad.
-- 
Simon Farnsworth