CAT3 vs. CAT5

[rbertram]

I just setup a wireless Internet connection. My antenna plugs into a Linksys router w/f port switch. If I connect into the router/switch with my PC, down/up speeds are correct. When I uplink the router to another 16-port switch, my download speeds are cut by a third, but the upload is still ok.

So I started playing around with different CAT5 and CAT5e cables and found no difference. When I tried a CAT3 cable, the download speed went back to normal. To confirm that my CAT5 cable was ok, I cut one end off and converted it to CAT3, and it worked perfectly.

Why would I get higher download speeds with CAT3? It is not a big deal since the broadband connection is only 2.5Mbps, but it prevents me from get higher network speeds in my LAN if I want to use the other 3 ports on my router.

 

[rbertram]

For the internet testing the second test was also through the 16-port switch. The only difference between the two sets of test was the uplink cable.

Some of the second set of tests were done with a purchased CAT3 cable that only has the Tx and Rx pairs. The rest of the second set of tests were done with a CAT5e cable that only had the Tx and Rx pairs terminated.

I also agree that the problem is in the uplink between the router and the switch. I just cannot figure out why the extra pairs are causing a problem.

I am not sure what you were asking for when you said, "I'd want to know that you only used IP for your testing." For PC to PC testing, I was testing throughput from IP to IP. For the internet testing, I am not sure how the test is done, since it is all done through a Java applet.

I have not set up any additional firewall or filtering yet. Everything is pretty musch at the default settings that the router was shipped with. The only change is that I am forwarding one port for a remote VPN connection.

 

[bigdog175]

Just a thought but is the switch configurable meaning can you manually set the specific port in question to 10mb or 100mb instead of leaving it set to auto negotiate, I know on a Cisco switch sometimes a connection left to auto negotiate has slower thru put even if it reports the link to be 100mb, I have experienced this personally.

 

[rbertram]

Unfortunately, it is not a managed switch, and there are no manually configurable speed settings on it or the router.

 

[Grenage]

Is it at all possible that the cables you are using are badly terminated ?

 

[rbertram]

I highly doubt it, but anything is possible at this point. If they were not terminated properly, wouldn't that have shown up on my PC to PC LAN tests? (See post #12 for LAN testing)

 

[Grenage]

Yes your right there, I guess I'm grasping at straws

It's very bizzare.

 

[rbertram]

Just as an update, the problem seems to have been solved.

Dropped the max Tx rate on the wireless antenna to 10 Mbps. It used to be set at 100Mbps. The max DL rate for my broadband connection is 2.5Mbps to the 10Mbps is more than antiquate.

The only thing I can think of is that the antenna is powered through the Cat5 on the brown pairs. For some reason, it may have been causing interference.

My wireless broadband service is supposed to be 2.5Mbps burst (for 12MB) down and 512Mbps down/up normal rate.

2003-05-06 15:19:25 EST: 2664 / 495
Your download speed : 2664134 bps, or 2664 kbps.
A 325.2 KB/sec transfer rate.
Your upload speed : 495949 bps, or 495 kbps.

 

[Bobg1]

I believe you mean 512K not M.
If someone has you thinking that you can get 512M, they are
feeding you a line.

 

[rbertram]

Your right - just hit the wrong key.