Cisco Support Community
Showing results for 
Search instead for 
Did you mean: 
New Member

1000BaseSX Connectivity Trouble _ Need Help

I have 2 Cat2924's tied together with 2 1000SX GBICs.

I have a green light on both ends. When I first setup the switches I thought everything was OK. HPOpenview detected the far end switch but soon after installation it lost connectivity and was going up and down but more down than up. A client tried to place a device on the far end switch but could only ping at a ratio of 1 to 30.

I tested the fiber (62.5 MM). I was within 200ft. but the dB loss was 7.6 and 8.1

All mechanical ends....ick

I Spliced one of the barreled connection which brought the loss down to 4.6 and 5.6 which is within the 7.5 loss allotment for 62.5 MM on the SX GBIC.

BUT I am getting the same results.

I can't ping from the far end switch but I was able to get a DHCP address which was curious. So I turned on sniffer and could see the network from the far end switch but I still can't ping out.....

Near end switch 'sh int' of the gig mod shows:

5 minute input rate 0 bits/sec, 0 packets/sec

5 minute output rate 28000 bits/sec, 28 packets/sec

so nothing is comming from the far end switch, but the lights are still green??

My question is:

Is there a configuration step I am missing?

Everything is VLAN1 so I don't know what it could be.

Or am I off on the dB loss specs?

I am pretty sure it is 7.5 dB worst case for 1000SX over ~160ft of 62.5 MM

This is my first set of 1000SX GBICs but there are many more to come. So if you know of anything I am missing please let me know.

New Member

Re: 1000BaseSX Connectivity Trouble _ Need Help

Please check if the distance between the GBIC port and the attached device exceeds the GBIC cabling guidelines.

Here are some troubleshooting docs. Hope it helps:

CreatePlease to create content