10/100 Mbps Throughput Issue

[leeym]

Until recently, (2) WinNT 4.0 machines (800 MHz, 256 MB RAM) in our office were on their own network connected via a NetGear 10/100 hub. These boxes were independent of the office's main network due to security issues the previous network admin couldn't overcome. Basically, one acts as an application server (User 1) for the other (User 2). No performance issues existed between either boxes.

About a month ago, both machines were replaced with WinXP Pro SP1 machines (2.6 GHz, 512 MB RAM), and were added to the main network. Both were reconfigured the same as before the migration. Here's the overview of our network: We have cable modem attached to a 4-port Linksys 10/100 router/switch which is connected to a 16 port HP ProCurve 10/100 switch. All users and servers are connected to this switch. We are operating in a Windows domain (vs. workgroup) environment. Note: Whether these boxes are connected through the router or switch doesn't matter.

Here's the issue: Once the new boxes were up on the new network, User 2 (client) started taking a huge performance hit. Remember, this machine relies on the database on User 1 (server). I verified that the NIC is running at 100 Mbps, and that the router or switch connecting the boxes are at 100 Mbps as well. However, I was just told that the RJ-45 connections MUST follow the protocol outlined at http://www.tcnj.edu/~nts/network/rj45_info.php. Is this true? Note that I've crimped the jacks in the following order: Blue, blue dotted, brown, brown dotted, orange, orange, orange dotted.

If following the protocol from that URL must be true, how come I'm getting green lights across the board in terms of 100 Mbps connectivity? I've checked everything with the application vendor, and verified that it is definitely a networking issue. Plus, after transferring the entire database to User 2 so it could access te database locally, the application's perfoamnce issue disappeared. This confirmed that a netorking issue exists.

Any ideas?

Thanks

 

[spidey07]

You must follow 568a or b wiring standards, otherwise you will get horrible performance. A link light is never a sign of a good network connection, all it means is your getting a link pulse on the receive pair of the NIC.

It is also generally best to use pre-made patch cables because that takes the guess work out of "could it be the cable or my crimping?"

We could go into the whys of why the performance is so bad, but its best to just stick to 568b everywhere and not worry about the cabling.

-edit- I'm bored so I'll ramble a little bit. Ethernet uses pairs 2 and 3 of a cat 5 cable. The orange pair and the green pair. Following 568b this is pins 1,2,3,6 on the jack. The entire reason ethernet works is because it runs on TWISTED PAIR cable. It is the twist and pair that allow is to cover long distances without much trouble. In your scenario you've lost the pairing in what is called a "split pair" which means you only have one wire of the pair in the right pin. Its quite common to see this in network installations and is probably the number one cause of performance problems.

hope this helps, and in the future remember that most network problems are caused by the physcial layer (cable)

 

[CryHavoc]

you will also want to check to make sure your nic loaded up at 100/full.
if its sitting at 100/half, you will see lots of FCS errors and collisions and your throughput will be horrendous.

Buy premade cat 5 patch cables to eliminate the wire as a cause of your problem.

Definitely check to see what the nic binds up at 100/full or 100/half.

 

[gunrunnerjohn]

You don't have the pairs wired properly it appears. Performance will suck with those cables, if it works at all.