Adapter teaming and different switches

[Jonas Back_2]

We're running Windows 2000 on a server and want to use adapter teaming mostly for failover when the link goes down on either of the cards (when the adapter or the switch goes down) but also, if possible, to load-balance.

If I look at the manual ALB (Adaptive Load Balancing) can only be used if all adapters are connected to the same switch. Is that correct? In that case, if we really want to connect it to different switches, AFT (Adapter Fault Tolerance) is the only option for us?

Is it possible to use ALB/FEC on two adapters connected to switch 1 and make some sort of AFT between the adapter connected to switch 2 and the "virtual" adapter in switch 1 to get greater bandwidht to the server?

Any ideas and experiences when it comes to adapter fault tolerance?

Both switches are Cisco 5500.

[Fernando Abrantes]

BOTH CARDS MUST BE CONNECTED
TO THE NETWORK,IF YOU CHOOSE
LOAD BALANCING IS THE BEST
BECAUSE YOU HAVE DOUBLE
BANDWITH AND FAULT TOLERAN??E
IN CASE OF ONE CARD FAILS.

[Jonas Back_2]

I know you can do that. We have tested it in a test-environment when connected both adapters to the same switch. It worked fine.

But according to the Installation Guideof the HP-NIC found here: http://h200004.www2.hp.com/bc/docs/support/SupportManual/lpn10823/lpn10823.pdf
on page 33 it says: "To use ALB, your adapters must be configured as a team in
your server and be connected to the same switch."

We haven't had the oppurtunity to test this. Have you?

Because we really want to connect the server to two different switches in case of one of them going down and still use Load Balancing.

Any ideas?

[Erwin Zoer_1]

Hello Jonas,


Regarding going to different switches, based on experience, the only supported solution for any of the fault-tolerance/performance options is to go to ONE switch.

For ALB/FEC trunks this maybe more easily understood as both the NICs and the switch negotiate parameters to setup the mode of operation. This does not work if the the adapters are going to different switches because the switch expects multiple NIC links to be connected to itself.

For AFT it is, in my personal opinion, more a supportability restriction, than an actual technical requirement. I know of customers using AFT going to multiple switches and this works fine. It is not supported, however.

The question about using two ALB/FEC teams going to different switches as an AFT team will not work as I see it as the software does not support these configurations.

I hope this helps.


Erwin Zoer

[Julio Valero]

The following configuration is tested and running for almost 1 year in our network:

Netserver with 3 HP NIC's
OS: Windows NT 4.0 SP6a, latest patches.......
This is the interesting one for you folks.
2 NIC's are configuring in an ALB team, each NIC is connected to a different CISCO switch.
The maximum downtime when some os the switches comes down is 5 sec's for incoming packets.
The maximum downtime when the switch is back is 0 sec's for incoming/outgoing packets.

FYI: the driver uses all of the NIC's for outging packets but only 1 for incoming packets. it means you have 100 mb's x number of nic's to serve files and 100 mb's for receiving files from the users. It assign a virtual mac to the ALB team, so the CISCO switches have to address incoming packts to only 1 of the ports, the primary one is which receive the packets, and the secondary takes over the reception of packets when primary NIC does not have link to the switch.

[Seth Cohen]

I am having similar issues.

When using SLB teams across 2 6509s, the servers will drop packets unless you disconnect/drop either port, then normal operation resumes.

This happens with drivers from smartstart 5.40. We've tried updating to the most recent teaming software and NIC drivers, but that does not work either.

The MAC of the team exists on both catalysts.

Settings are SLB / balance w/ IP.

So far we have not been able to find a fix using load balancing. A while ago there was a Compaq document that said that SLB was available across multiple switches, depending on the switch. We haven't been able to get any more info from Compaq or Cisco about it.