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Teaming network interface cards may sound like a wonderful idea, but you still need to plan carefully where to put the server and ensure that you have enough free ports on your switch to support such an action. When connecting our test machine, we used four ports. On a 24-port switch, this left only 20 ports available to clients. A possible solution? Attach another switch to the network to allow more clients to connect.

Too bad it's not that easy to do. To keep those 400 Mbps of possible throughput, you need to trunk the two switches together. Trunking switches is virtually identical to teaming NICs, and people have been doing it for years. To trunk 400 Mbps between two switches, you need four free 100-Mbps ports on each switch. Trunking together two 24-port switches will yield only 40 client connections, less the server connections. If your switches do not support trunking (and sometimes trunking between different vendors' switches doesn't work), then you have even more problems on your hands.

For trunk-deprived switches, you can simply fan out to more switches. By splitting 40 users among four switches, each group of 10 users would have up to 100-Mbps access to the server (see "Add Switches Without Trunking," above).

Trunking Boosts Bandwidth Click here to enlarge

So 10 users are connected to each switch, and each switch is then connected to one port of your TNIC. Unfortunately, the 10 users in each group are sharing their 100-Mbps access, so if User A and User B are in the same group and try downloading at the same time, they get an effective rate of 50 Mbps.

If there are two trunked switches, each user gets 100 Mbps (see "Trunking Boosts Bandwidth," at right). However, if User A and User B are in different groups (connected to two different switches), they can both access the server at 100 Mbps. Do a simple analysis of your network and determine from where traffic is expected to come -- and how often. This can help you decide if your infrastructure needs to be enhanced or upgraded.

Don't forget that many newer switches come with Gigabit Ethernet uplink ports. A four- or eight-port 100-Mbps switch with a gigabit uplink port will work fine, and with a gigabit connection there is no need to worry about trunking. And you can connect multiple 100-Mbps switches using Gigabit Ethernet. This is a little more expensive, but it'll help you integrate your network with a Gigabit Ethernet backbone. You don't have a gigabit backbone? Then remember rule No. 1: Always plan ahead.