My office environment contains both wired and wireless networks. For continuity, my Windows XP notebook, which goes where I go, also has both wired and wireless connectivity. I can take my notebook to meetings and have access to network resources and email without a wired connection. When I'm at my desk, I connect the notebook to its docking station and use the faster wired connection. (See also, "Solving 3 Wireless Networking Problems").
However, a minor annoyance has cropped up. After I switch to the wireless network, the computer routes all traffic to the much slower wireless network. In most cases this isn't a problem, but when I try to copy files to take home or take on the road, I get a message saying the file copy will take anywhere from 5 minutes to 50 minutes, depending upon the size of the file. At this point, I realize that the connection traffic is all on the wireless card, and the only way I can force the traffic back to the wired network is to disable the wireless card. A conversation with other wired/wireless network users in my office discovered that almost everyone else was having the same problem.
A call to Microsoft confirmed that the OS should always default to the fastest network connection. When I ran the usual network diagnostic tools, I didn't find anything odd in the configuration of the network adapters, and switching to a different brand of wireless card didn't make a difference (the wired network adapter is built in to the notebook).
A little more research uncovered the problem. In XP, the default interface metric for all network adapters is set to Automatic, which causes the adapter to use the fastest available connection. But for some reason, the wireless card installation program had set the wired interface metric to 1 and left the wireless interface set to Automatic. This change had the effect of setting the wireless metric to 0 (although you can't actually set the metric to 0, XP gives priority to an interface metric set to Automatic over an interface metric set to 1). The OS uses the lowest-numbered interface (in this case, the automatically set wireless interface) for all default network traffic. Resetting the interface metrics for all network adapters to Automatic returned the default behavior and gave priority to the fastest network.
If you run XP and you've experienced this problem or want to check your current configuration, perform the following steps:
- Open the Control Panel Network and Dial-up Connections applet. Right-click Local Area Connection and choose Properties.
- Select Internet Protocol and click Properties.
- Click Advanced.
- Make sure that the Automatic metric check box is selected. (If you want to force a particular connection to be primary, clear the Automatic metric box and enter interface metric numbers, from lowest to highest.)
If you run Windows 2000, the OS can't automatically set the interface metrics, so you must manually set them.