[clue] [tech] ethernet bonding versus bridging?

[Jim Ockers]

Hi CLUEbies,

Maybe I am the only person with this question but I was wondering if 
someone could help me understand the pros and cons of ethernet bonding 
versus bridging.  I even googled it but didn't really find a good 
explanation of why I should use bridging instead of bonding or vice 
versa. 
http://kaivanov.blogspot.com/2010/09/network-card-bonding-on-centos.html

I've always just used bridging (brctl add br br0 ; brctrl addif br0 eth0 
; ...) to, um, "bond" multiple ethernet interfaces together into one 
apparent ethernet interface.  Bridging seems automatic and wizzy and 
seems to just work, it's like having an ethernet switch in the box with 
multiple uplinks to the next switch.  Automatic fault tolerance, and 
without doing any serious performance testing I thought you would get 
more bandwidth/throughput (in both directions) by creating a bridge and 
putting the physical NICs in the bridge.

Is this not the case?  I see that bonding has a bunch of different modes 
you can set based on what you want it to do, and one of the modes is 
transmit load balancing.  I also see that you can do traffic shaping/QoS 
with tc and various qdiscs and I guess I've never needed or tried to set 
that on a bridge interface.

Anyway if someone out there knows all about both of these concepts 
{bridge|bond} and cares to illuminate me and this list a bit about 
what's better about each and why to use one or the other, I would 
appreciate it.

Thanks in advance,
Jim

--
Jim Ockers, P.E., P.Eng. (ockers at ockers.net)
Contact info: http://www.ockers.net/