NLB

Mishra

Does anyone know the technological reason for not being able to have NLB members in separate subnets? I can't think of any reason why... Obviously broadcasts are a question here but what would you need to broadcast when you know the direct IP address of the other member in the NLB?

"Network Load Balancing clusters have a maximum of 32 hosts, and all of the hosts must be on the same subnet."

That is just crazy

sprkymrk

Because NLB runs as an intermediate driver between the TCP/IP protocol and network adapter drivers.

This allows it to maximizes throughput by using the broadcast subnet to deliver incoming network traffic to all cluster hosts and by eliminating the need to route incoming packets to individual cluster hosts.

Got that from a MS White Paper.

Mishra

Thanks sprkymrk.

I think that is totally insane. If they had the option to incorporate it into different subnets with a tiny bit of performance hit then they should have let it be in different subnets. The reason is because fail-over servers often reside in different locations on different subnets.

Oh well. At least I know now. And knowing is half the battle.