Upgrading and Repairing Networks

Using Gigabit Ethernet for High-End Servers

Another upgrade you might want to perform using Gigabit or 10 Gigabit Ethernet is for server connections. A single file server connected to a switch can be limited by the total bandwidth of all the workstations that connect to it through a single switch or a cascade of switches. For a high-end server, the CPU(s) and disk array (which could even be a fast storage area network) might not be the bottleneck where performance is concerned. Instead, you might find that you need to use multiple network adapter cards and make several connections between the switch and the server. Whether or not this is the situation, upgrading the server by using Gigabit Ethernet cards can dramatically increase performance. The switch can perform buffering between lower-bandwidth workstations and the server that's now equipped with much faster adapter cards.

A good way to determine whether the network card is the bottleneck is to use a good network analyzer to determine the utilization of the connection between the computer and the switch. If it's approaching 80% (in a full-duplex connection), you should definitely consider replacing the network card.

The other component you'll have to replace is the switch to one that supports Gigabit Ethernet. That doesn't mean you have to replace any downstream switches because they will feed into the new switch, with network traffic being funneled into the server by the new switch that supports both Gigabit Ethernet as well as Fast Ethernet ports for connections to the other switches or workstations.

Gigabit Ethernet to the Desktop?

Ethernet adapters that you can use in desktop workstations are available now. However, there's no reason to consider placing them into a typical user's workstation. Unless you also replace the switches between the workstation and the server(s) it uses, the switches that lie in between become a limiting factor.

But if your business involves such things as video editing or other high-end graphics applications, swapping out old adapter cards and switches might be a good idea. The main thing to consider here is whether the workstation can handle the Gigabit Ethernet bandwidth that the adapter provides. Again, use performance monitoring to be sure that the TCP/IP stack or the CPU of the workstation is not a limiting factor that makes the Gigabit Ethernet card merely something to talk about. If the workstation can't process the bandwidth that the card can deliver, you're wasting money! Use the cash in other parts of the network (such as the backbone)!