Do you have a PC in your office that just doesn't act right? Perhaps it's configured just like every other computer in the office, but it works much more slowly than the others. If you are shaking your head right now, your problem may be caused by an excessive number of dropped packets--which can be the fault of bad wiring. In this article, we'll tell you what you can do to fix such a cable problem.
Symptoms of dropped packets
Usually, the symptoms of excessive dropped packets are slow response time from the network (especially during login) and possibly frequent time outs. If you experience such problems, it's generally caused by a short in your patch cable.
Even in such a situation, though, several variables control the system's overall behavior. For starters, the severity of the short plays a big part in the system's behavior. Obviously, the more severe the short, the more packets will be dropped, and the more likely that the computer is to time out while waiting on network resources. Another factor is the protocol or protocols that you're running. Some protocols have longer time-out periods and allow for more retries than others. Computers running multiple protocols are also less likely to completely time out while waiting for a response from a network resource that's also running multiple protocols. This is the case because when one protocol has timed out, Windows will try the next protocol that's bound to the NIC.
Diagnosis and solution
The easiest way to check for a faulty patch cable is to look at the link light on the back of the PC while jiggling the patch cable. Most shorts occur where the end is crimped onto the cable. If the link light goes out while jiggling the cable, you've got a short. You should also repeat the process on the end of the cable that connects to the hub.
If the link light doesn't go out, it doesn't necessarily mean that no problem exists. A short may not be severe enough to cause the link light to indicate a failure. If you're having trouble tracking down a short, remove the patch cable from the computer and from the hub. When you've removed the cable, look at the end that gets inserted and check to make sure all of the wires inside the cable go all the way to the end of the RJ-45 connector. If a wire doesn't go all the way to the end, it may not be making good contact inside the connector--and it may be the cause of the short. If you find such a connection, try cutting off the end of the cable and crimping a new RJ-45 connector onto the cable.
If you would prefer a more scientific approach to solving this problem, and you're using the IPX/SPX protocol on a computer running Windows 98, you can use the System Monitor tool to watch for dropped packets. You do so as follows:
- Open System Monitor and select the Add Item command from the Edit menu.
- Select the IPX/SPX Protocol option from the category list and select the IPX Packets Lost/Second option from the Item list.
- Click OK to add this counter to the System Monitor.
Now, you can see exactly how many IPX packets are being lost during routine network communications.