PowerConnect 2748 + Linux + link aggregation

[Thomas_Chenault at Dell.com]

I see now that the 2748 specs do in fact list 802.3ad. Whether or not
that includes LACP remains unclear to me. If LACP is not available, then
the 2748 LAG would be appropriately paired with a balance-xor bond. The
balance-xor bonding mode should provide both load balancing and failover
without introducing packet reordering issues, just as the 802.3ad mode
would were LACP present. From the perspective of the bonding module, the
key difference between 802.3ad mode and balance-xor mode is whether or
not LACP is used.


Thomas


-----Original Message-----
From: Steve Thompson [mailto:smt at vgersoft.com] 
Sent: Friday, March 02, 2007 11:36 AM
To: Chenault, Thomas
Cc: linux-poweredge-Lists
Subject: RE: PowerConnect 2748 + Linux + link aggregation

On Fri, 2 Mar 2007, Thomas_Chenault at dell.com wrote:

> Based on a quick browse through the documentation, it appears that the
> 2748 may not support 802.3ad/LACP. Assuming that this is true, the
> appropriate solution would be to choose a different mode for the bond,
> balance-xor perhaps.

Very interesting. The 2748 is advertised as supporting 802.3ad, however,

and indeed it does work if I do not configure any LAG groups on the 
switch. In this case, the two interfaces show up with different
Aggregate 
ID's, and all traffic goes through one interface only. Failover to the 
second interface does work if I pull the cable to the active slave. I'd 
like to load balance, however, while avoiding as much as posible any 
packet reordering issues; is this not going to be possible with the 2748

with the bond in 802.3ad mode?

Steve