I've done this before on both Windows 2003 and Linux (RHEL 3.x and 4.x) but I'm scratching my head on how I actually got it to work so hey, might as well ask it here and see what people say.
I have a Windows 2003 RC2 SP2 blade (poweredge 1855) in a chassis with passthru modules. In essense this gives me two 1Gbps NICs. I have one passthru going to a powerconnect 5324 (call it sw1) and the other going to an identical powerconnect 5324 (call it sw2).
Each of sw1 and sw2 have a LAG made up of two gb ports connected to a central switch (call it sw3).
sw1 and sw2 are not directly connected. Links between sw3 and sw1/2 are in trunk mode, LAG and have 5-6 VLANs tagged on them
Intel Proset is running on the blade
What I want: whichever port config that allows for redundancy between the two connections to sw1 and sw2. Example: after set up and running, I want to be able to have sw1 or sw2 die and windows box not lose any pings.
I know in the past this was with the 802.3ad configuration, and I've set that up but when I unplug one of the connections, the whole box loses connectivity and I have to go in on console and tell it to fail over to the working connection. I know in the past, this worked but I can't remember the exact config I used so that it does work.
More important: no loss of connectivity when cable unplugged or switch dies
Less important: bandwidth aggregation (I'm ok with only getting 1gbps)
Note: the kicker here is that each network connection is physically connected to different switches. If both NICs were connected to a single switch, then this would be cake. But they're connected to separate switches. Also, I don't want the standard 30+second convergence time of STP or other methods. I really want there to be no pings lost if something get disconnected.