3com 4200 Switch fiber connected going wild

[bch123]

Hi all, strange problem, having 2 x 3com switch 4200 connected to each other via GBIC SFP tranceivers.

We use a converter ( the old installation was with stp connectors) converting from STP to SFP.

Just plugging those two together, the fiber is around 110 meters.

One of the switces is connected to the Server (Windows 2003 Standard), the other switch is connected to 10 workstations and 3 jetdirect printers.

After running the application on the PC's in the Fiber end of the Switch for around 5-10 minutes, the application totally locks op, as there is no more access to the server,
then you must use task manager to kill the application.

Does anyone know if the way we have connected is ok ??.

It looks like something around filelocking is going wild,
internet and e-mail (pop and smtp) is not affected.

any idears ???

Regards bch123

 

[IRudebwoy]

What make you think it is a switch problem? If other types of networking protocols are working over the same link (during the problem) then it is not a layer 1-3 problem. Maybe it could be a mis-configured Spanning Tree Protocol if the switches are connected by 2 or more links.

I have a few more questions.

During the outage can you ping the server?

Where is your internet gateway in relation to the client?

Where is your POP3 and SMTP server in relation to the clients?

How do you recover from this outage?

Is it fiber from switch to switch? No converters.

 

[bch123]

hi IRudebwoy


I will try with some more info.

The Switch who has the server connected, also has the internet router connected, there is around 15 PC's and printers in the same switch, and there are not affected, is is only in the remote switch the problem happens.

During the outage can you ping the server?, I am not sure.

Where is your internet gateway in relation to the client? se above.

Where is your POP3 and SMTP server in relation to the clients?, external internet mail.

How do you recover from this outage?, I switch back to the old 10MB Superstack hub, so the connection between the 2 new switches is old superstack hub with 2 x 10mb fiber connections.

Is it fiber from switch to switch? No converters. no there is STP to SFP converters

hope that helps

regards bch123

 

[IRudebwoy]

At 110 meters the run is too long for copper. And using media converters only makes the problem worse. You need fiber from end to end or keep using the hub @ 10Mb. At that length any packet transmitted will generate junk packets at the receiving end and the re-transmits will choke your link as you have experienced. At higher speeds and longer lengths your cable run needs to be near perfect. Take a look at your packet counters on the link. I bet you a lot of fragmented packets and CRC errors.

I have many copper runs that inherit noise from the environment (manufacturing facility) and they work fine at 100Mb. If I decided to move to 1Gb I would have to re-run almost all my drops because the noise level would cause more problems at that speed.

Have Fun!

 

[MaCarvalho]

I agree with IRudebwoy. It´s clear that at bigger speeds with that distance the angle that the beams will take will be such that they will be arriving at diferent times and so, will be read in diferent "windows". That´s why the manufact. ivented the sigle mode fibre. Now this is one thing. Now join a converter and thent you´ll have a problem.

Cheers