bfranks
join:2002-06-22
Arlington, VA
| Strange Issue with 3Com 3870
Hello,
We are seeing a very strange/frustrating issue with two 3com 3870 switches.
Our setup looks like this
Computer A (GigE) Switch 1 (gigE) Media Converter (Fiber Run) Media Converter (gigE) Switch 2 (gigE) Computer B
We have a cross connect in our data center that uses media converters (fiber) to regular 1000FD on each end.
Each end of the 1000FD handoff is plugged into port 1 of the 3870's (switch 1 and switch 2).
Pinging from Computer A to Computer B we receive a 50% packet loss.
Pinging from Computer B to Switch 1, no packet loss.
Pinging from Computer A to Switch 2, 50% packet loss.
Looking in the interface, the port 1's on each switch auto negotiate to 1000FD, however flow control shows as off.
We asked our data center to run tests on the media converts and fiber runs and everything comes back 100% fine. Has anyone seen a weird issue like this before with 3com switches not playing nicely with media converters?
I have no clue whats going on and our data center said the fiber run/media converter is fine... Help!?  |
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skinsfanusa
join:2001-03-09
San Marcos, CA | Is there another computer( Computer C) that you can ping on switch 1 from Computer A?
What about using the CLI in Switch 1 to ping Switch 2?
Do you know how long the fiber run is? |
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bfranks
join:2002-06-22
Arlington, VA
| Hey Skins fan, yes anything connected to switch 1 can ping something else plugged into switch 1 no problem. therefore I don't believe switch one is the problem.
Switch 2 is fine pinging other items connected to switch 2 no problem as well.
Switch 1 and Switch 2 can ping each other, however I am somewhat concerned with this type of test as the CLI only sends one ping probe and it usually succeeds. The first ping probe usually works from Computer A to Computer B, however we then start seeing 50% loss.
The length of the fiber run is between Equinix buildings on the DC campus and I believe is less than a mile. |
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skinsfanusa
join:2001-03-09
San Marcos, CA | reply to bfranks
Is the fiber run single or Multimode?
If it's a multimode cable, that could be the problem. |
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