[c-nsp] GigE Link Problem

[Mark Taylor]

Thanks to everyone for the replies, I resolved the issue in the end. It 
turned out that 3 fiber cables out of a batch of 4 were faulty and these 
were all brand new cables. It wasn't until after persevering that I actually 
got to the 4th cable, as you can imagine I wouldn't have thought it'd be 
necessary to try that many.

These are Cisco Gbic's and SFP's and all 1000BaseSX, but thanks for the 
suggestions.

Cheers,
Mark.



> Mark,
>
> Is the SFP GBIC from Cisco?  Is it a 1000Base-SX or 100Base-FX?  I had
> originally thought that an SFP was an SFP (was an SFP) but I ran into a
> situation a couple months back where I discovered that the 3750 is a
> little picky about the SFPs used in the SFP ports.  I had tried one from
> Nortel and it didn't work out.  After speaking with the Cisco-TAC they
> told me it had to be one of theirs, which I find a little hard to believe,
> but I changed it out and voila, it worked.
>
> There is a command you can use to check the hardware state... I think it's
> "show interfaces properties detail" or something like that.  I don't
> remember and I don't have a switch handy to look at, but I think this will
> tell you the state of the SFP or GBIC, like if it is unrecognized hardware
> or whatever...
>
>
> Scott
>
>
>> Sorry if this does re-post, but I don't think it made the list originally
>> due to a problem at my end:
>>
>> Hi,
>>
>> I am connecting a 3750-48TS switch to a 2948G switch with Gigabit
>> Ethernet.
>> The 3750 has a 1000BaseSX SFP port (GLC-SX-MM) and the 2948G has a
>> 1000BaseSX GBIC (WS-G5484). These are connected together with a 3m length
>> of
>> SC-LC multimode fiber.
>>
>> I cannot get the link between the two switches to establish. I have tried
>> reverseing the TX and RX on the SC end of the fiber, using different
>> fiber,
>> using a different GBIC and using a different SFP.
>>
>> I have tried "set port negotiation 2/50 enable" on the 2948G which didn't
>> work. When I turn off this negotiation on the 2948G using "set port
>> negotiation 2/50 disable" it displays a link light and connected status,
>> but
>> the 3750 shows a down port. You cannot force the speed or duplex as the
>> ports have a fixed config of 1000 full.
>>
>> Does anybody have any ideas why this might be happening and configs which
>> will make it work?
>> For reference the 2948G is CatOS and 3750 is IOS.
>>
>> Thanks in advance,
>> Mark.