100Mb SFP compatibility on 2960G switches

[NorskeskogTas]

Hi,

I came across an interesting scenario recently when a Cisco 2960G-24TC-L switch failed (4x ASIC dual SFP/TX ports stopped working)

This switch had a GLC-GE-100FX sfp downlink connection to 2940 which worked fine.

The only spare switch I had to replace the 2960G-24 was a 2960G-48TC-L which you would think being in the same family would be indentical but with more port capacity?

Here lies the question to Cisco:

Why on earth would you not make these two switches identical to the point where one requires a GLC-GE-100FX sfp (24 port) BUT the 2960G-48TC-L requires a GLC-FE-100 sfp to be compatible??

This to me does not make any sense what so ever - further more after spending hours tracing the problem with getting the link into full duplex, it has cost me another different sfp to get this link working.

When I used the GLC-GE-100 on the 48 port switch and set the media-type, the link would stop, so I checked the 100mb sfp compatibilty sheet and found the above to my complete amazement.

Both switches have GE dual sfp/tx ports so why the difference?

If someone can answer the above, I would at least know why cisco have done this?  

thanks             

[paolo bevilacqua]

Both switches you mentioned C2960G-24TC-L and C2960G-48TC-L support both FCL-FE-100FX and GLC-GE-100FX..

Table 2 second and fifth rows.

http://www.cisco.com/en/US/docs/interfaces_modules/transceiver_modules/compatibility/matrix/OL632702.html

[NorskeskogTas]

ok, I see that in Table 8.

I wasnt doing anything different between the two switches so that does not explain the results I was getting unless....

Maybe the GLC-GE-100FX Gbic is faulty?

I will test on another 2960G-24 and 48 port switch.

Thanks for the reply.

[Marcin Gaszewski]

Could you post #show inventory when sfp is inserted. Try to setup duplex and speed before inserting sfp.