Switching connectivity

rakem

this is a general question not directly related to the CCNA but still is relevent.

On most of our servers we have two NICs, these two NICs can be teamed to run under one IP address, which creates redundency because if one NIC fails then the other one will be running so the server wont go offline.

My question - to create better redundency, we are thinking about plugging the two NICs into two different switches. (Currently the two NICs go into the same switch) So if one switch fails then the server wont go offline. Will plugging two NICs into two different switchs create any looping problems? STP is enabled, but the switches wouldnt be connected by redundent paths.

Would this cause any other looping problems from broadcast or multi cast traffic?

what im thinking is that if a broadcast gets sent out from NIC 1, it will be forwarded out all active interfaces, except the originating one, which means it will be forwarded out the link to the other switch, which will in turn forward it out the port that has NIC 2 connected.... hmmm not to sure about this. Im a bit uneasy about setting it up this way and i just wanted some feedback..

edit: we dont have any VLANs set up either....

thanks

Danman32

It depends on how the NICs team. Do they have the same virtual MAC address, or they are different MACs with duplicate IPs?

In either case, both NICs have to be on the same IP subnet, therefore the two switches would have to be interconnected. In other words, both switches have to be in the same broadcast domain, since the two NICs have to be in the same broadcast domain.

Of course we would need to know about the rest of the network. Are there redundancies on all the other hosts? If not, again the two switches can't be completely isolated from each other, since the packet from either NIC has to get to the destination host that might be on the other switch, and the network stack on the server with NIC redundancy is going to be ARPing for the MAC address of the destination IP, since the destination is on the same subnet.

rakem

yes they team under one virtual mac address, with one IP address. There is noo segmentation between the switches, so they are all in the same broadcast domain.

The two switches will be connected to each other but only by i single cable. We have about 10 servers and we are thinking about setting them all up in this fashion. We have two 24 port switchs and one 48 port. All switches are connected to each other by a single cable, there are all in the same broadcast domain.