Cisco Catalyst 2950C 100BASE-FX - with Cisco 4500 GBIC

Unanswered Question
Jul 20th, 2010


I have the following switch at one end

Cisco Catalyst 2950C 24-24 10/100 ports and 2 fixed 100BASE-FX uplink  ports

connected via fiber to Cisco 4506 Module

WS-X4306-GBCatalyst 4500   Gigabit Ethernet Module, 6-Ports (GBIC)
WS-G54841000BASE-SX  Short Wavelength  GBIC (Multimode only)

with MM fiber.

Now my link is not coming up?

Do i need to put any additional commands to get the link up?

One side is 100 based FX while the other is GIG - GBIC .....will it be uncompataible?

Please let me know...


I have this problem too.
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Jerry Ye Tue, 07/20/2010 - 07:17

Fiber ports don't auto negotiate on speed. They must be match on both side.



rahurao Tue, 07/20/2010 - 09:20

Hi Nomy,

You have 1000 configured on the GBIC and 100 on the other side.

Try configuring the speed to have them communicate.

Sending you the link which will have the Gbic cards supported on your switch:


rahurao Tue, 07/20/2010 - 09:23

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HI Nomy,

I sent you the link so that you can have the correct Gbic for your switch as g5484 works on 1000 and other gbic x2922 works on 100, this is the reason you are not able to get the link up.

Here is the link again:

Please let me know if there is anything else I can help you with .

Have a great day !!



nomykhan Tue, 07/20/2010 - 21:41


Thanks for the answers.....but i have already purchased the

WS-G54841000BASE-SX  Short Wavelength  GBIC (Multimode only)

the following GBIC for the there a way to make them work? even if they work on 100?

i have already purchased the hardware and need a solution or work around?

will putting a GIG to FE fiiber convertor on the 4500 will solve the issue?


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