Channel Bonding

[Jakob Østergaard]

On Wed, Mar 28, 2001 at 01:57:30PM -0500, Timothy I Mattox wrote:
> Hello,
> Unless the 16 port switch can be configured to handle it (and most can
> not as far as I know), you would need two 8 port switches that are NOT
> connected together.  Some high end switches have a form of trunking
> (I'm not sure which flavor of trunking will work) that can properly
> handle having more than one connection appear to have the same MAC
> address.  Also, from comments here on the list, it seems that not all
> VLAN support is created equal, so splitting a 16 port switch into two
> VLANs won't necessarily work either.
> 
> The fundamental problem is that channel bonding makes several NICs in
> the same box have identical MAC addresses, and that breaks the most
> commonly used method(s) for routing ethernet packets inside of switches,
> since MAC addresses are supposed to be unique.

At work we use an intel switch that allows "trunking" of several ports.
however, a 24 port switch has three "groups" of eight ports each (or was it four
groups of six ? I forgot), and you can only do trunking between ports in the
same group, and you can only trunk once in each group. Thus, we can only create
three (or four) trunk "sets" for each switch.

This is very switch-specific - you should check the capabilities of your own
switch.   I think this kind of capability is becoming more normal in lower
end switches as well.

However, once the switch is set up to trunk a few ports, enabling it in RedHat
7 with a 2.4 kernel is so easy it's almost cheating   :)  It works very well
indeed.  The RedHat initscripts are prepared for this setup, so there's no
special hackery needed at all.  I don't know about other distributions.

It's correct that the kernel uses the same MAC on all NICs that are trunked,
but this is what the switch expects, and it's the only sane way to do it as I
see it.   And I don't know why VLANs got involved in this discussion at all :)

-- 
................................................................
:   jakob at unthought.net   : And I see the elder races,         :
:.........................: putrid forms of man                :
:   Jakob Østergaard      : See him rise and claim the earth,  :
:        OZ9ABN           : his downfall is at hand.           :
:.........................:............{Konkhra}...............: