Diagnosing a broadband speed problem

If I connect my computer directly to the modem the speed test shows 6148 down and 649 up. If I then connect the router to the modem and my computer the speed test is 3747 down and 647 up. Is the router not capable of that speed? Linksys did not recommend updating the software if it was working. Can this be corrected?

I have a 6-meg cable modem. If I connect my computer directly to the modem the speed test shows 6148 down and 649 up. If I then connect the router to the modem and my computer the speed test is 3747 down and 647 up. Is the router not capable of that speed? Linksys did not recommend updating the software if it was working. Can this be corrected?

— Jim Myke

Based on the information you are giving me, I would agree that the router seems to be the problem or at least a significant contributor to the situation. I beg to differ with Linksys – my first step would be to update the firmware on the router to the latest release. While the router may well be working, updating the firmware take out one variable as being part of the problem. If the speed problem still exists after the firmware update, then we can look at other possible issues.

Call up the router’s Web management console and look for speed and duplex settings. Some routers allow auto detect of both speed and duplex. It sounds like the router and cable modem are having a small problem in the auto-negotiation process.

If the Web management console offers the options to set both speed and duplex, I would recommend setting it to 100-MB speed and full duplex.

If this doesn’t help with line speed, try a different patch cable between the cable modem and router; there might be something wrong with the cable. Also, ask your cable-modem provider if there is a firmware update for the cable modem that can be applied.

What I am thinking about here is an update that help with the auto negotiation process that might be able to use a minor tweak to help with the difference between the computer you tested with and the firewall. If this still doesn’t resolve the problem, see if you can borrow a newer version of the router that might have a hardware design that is either newer or may address a minor problem that has shown up in the model you have.