Tweaks To Help Ensure
Better Router Throughput:

Ensure your NICs are working properly

A "chatty" NIC can flood the network with traffic, causing exceptionally poor performance. We speak from experience on this one! Bring up all of your computers, printer servers, and other IP devices and make certain they are not running any applications.

• On each computer bring up a browser and point it to this Website, which doesn't have banner ads or other activity-generating pages.
• Check the activity lights on the router and any switches. You should see occasional and random flickers on each port. An occasional pulsing of all channels is normal for Windows.
• If the activity looks OK, on each machine run a ping test (see below). You should see relatively stable ping times.

If you see a rhythmic "heartbeat" on all ports unplug the cable for each computer until you find the one causing the heartbeat. If one computer shows heavy activity unplug it before doing any futher fine tuning. Run a ping test (see below) on each remaining computer.

• If the pings look good re-connect the problematic machine. If the ping times suddenly increase or if you get time-outs you may need to replace the NIC in the offending computer.
• You can test that one computer's NIC by connecting it directly to the modem and pinging from it. .

Run a ping test from each computer

Ping is a command line utility that measures the time required to transmit IP packets to another system. A ping test will report if any packets are lost. Ping is run from a DOS prompt.

• Go to Start / Run. In the command box type command (Windows 98 and ME) or cmd (Windows NT, 2000, and XP) . This will bring up a DOS prompt.
• Type ipconfig /all. Note the numbers for the DNS Servers, i.e., 12.34.56.78
• At the DOS prompt type ping <dns address> -t to start the test.
  Using the above example that would be ping 12.34.56.78 -t.
• Ping times should be relatively consistent, i.e., 10-30 msec. Occasional longer times are normal. Extremely long ping times or frequent time-outs are an indication of trouble.
• After a few minutes type Ctrl-C to stop the ping (hold Control and press C).

Note that running ping with the -t option for more than a few minutes causes extra traffic on your ISPs servers. For a quick text you can ping any Website. Some may not ping properly and theat does not indicate a problem with your system.

Set the MTU for the router and the workstations

MTU is the Maximum Transmission Unit. If the setting is too high packets can fragment and transmission speeds will be poor.

The default MTU is 1500. A DSL connection with PPPoE cannot be above 1492 and the default settings could cause problems. The MTU should be set the same on both sides of your router, the internal LAN (your network) and the external WAN (the Internet).

Ask your ISP for their recommend MTU setting. If they won't give it to you continue reading below. Verizon recommended using 1492 for their DSL with PPPoE, however, our testing showed that 1490 works better.

To find the proper MTU Size you will have to do a ping that tests for fragmented packets. Refer to the ping test, above, to learn how to find your ISPs DNS server address. We will use 12.34.56.78 in the examples below.

At the DOS prompt start the special ping using a value of 1472. Work down in jumps of 10 until the packets are not fragmented. The syntax is: ping 12.34.56.78 -f -l <test value>. Below are results from a sample test.

Start at 1472 and work your way down by 10 each time. Once you get a reply, go up by 2 until you get a fragmented packet.

Check your router documentation to learn how to set its MTU. For the Linksys open a browser and enter http://192.168.1.1/Filters.htm into the address bar. When asked, enter the password. The MTU setting is near the bottom of the screen. Enable it and enter the optimum value. Click Apply to save the setting.