Trunking a dual nic server help

[Andy White]

Hello,

I need to move our Dell backup server from our Nortel switches to our Cisco switches.  I have 2 stacks and I want to put one LAN cable in one of the Cisco stacks and one in the other Cisco stack, how shoudl I configure the 2 ports on the separate stacks and what settings on the Server software should I use as the teaming software lets me choose the follwoing:

Generic Trunking (FEC/GEC)/802.3ad-Draft Static (which it is currently set to)

Smart Load Balancing(TM) and Failover

Link Aggregation (802.3ad)

SLB (Auto-Fallback Disable)

Here is a simple diagram, the VMware infrastructure which I need to back is split between the 2 stacks, but I also have server off the Nortels that need to be backed up too.  Which the ports just be a general trunk ports and the server software be set to one of the above options?

Thanks

[Gregory Snipes]

Since you are connecting the sever to two separate stacks of 3750s you cannot use any kind dynamic link aggregation protocol like LACP. This means that the fault tolerance will need to be entirely on the server side.

Configure the switchports on the 3750s as regular access ports. I would recommend setting the server to smart load balancing and failover. This will be the best solution for your current aritecture.

Best regards,

Greg

[Andy White]

Thanks Greg, I was worries about creating a loop, but I guess it will use the 2 phycical mac addresses that are in the team?

[Gregory Snipes]

Internal server NIC redundancy is it's own kind of black magic. LACP is preferable if you can do it as the redundancy is negotiated by both sides. However, in the configuration you are trying to use this is not possible as you are connecting to two separate non-vpc capable switches.

That said I have never seen a spanning tree loop or any other major problems caused by this kind of configuration. You should have no issues with using the described configuration.

Glad to help,

Greg

[Andy White]

So it was to use LACP then I would need to create a trunk in each switch?  Also Greg what is non-vpc?

Thanks

[Gregory Snipes]

VPC is virtual port channel, it is a technology developed by Cisco to allow negotiation of port channels (including LACP PCs) to physically separate switches. It is however, only available on the Nexus data center switch line. Absent this technology, it is not possible to connect a port channel to two separate switches. The only way to use LACP in your situation would be to convert the two separate stacks of 3750s into a single stack.

[Andy White]

I understand Greg, I only mentioned the loop issue as I thought the mac address tables on the swithes would see the virtual mac address of the server form different ports, as the ports from the Cisco switches to the Nortel switches are etherchannels and not single trunks so STP isn't blocking some of the ports.

[Gregory Snipes]

Server NICs that use NIC teaming are not supposed to send their MAC address out more then one port at one time. Only one of the links will be used for incoming traffic, but traffic will be sent out both links. I have seen a MAC flap between the ports sometimes but that does not cause any kind of loop. However it can cause other issues, do not run port-security on the ports connected to servers with this kind of NIC teaming. Running port securty is pretty much a garuntee this server will at some point go down because of it.