3550 GBIC question

Hi,

Depends, do you have to GBICs connecting two switches up or have you just put the GBIC in the switch and not connected it to anything?

Cheers

Matt

thanks for your reply. i try to power on alone(one switch). and i also try to stack with the

2900XL with fibre. only 2900XL side the led is green. but no led in 3550.

thanks paul Matty M =E5=AF=AB=E9=81=93=EF=BC=9A

Hello,

which GBIC do you have (e.g. the 1000BASE-SX GBIC, 1000BASE-LX/LH GBIC, or the GigaStack GBIC) ? Make sure you are using the right cable (check the link below for the different GBICs and the fiber modes supported). Also, check if your cable might be faulty: connect both receive ends of the cable to the same GBIC, if the cable is ok on the receive end, your GBIC LED should light up. Do the same with the transmit ends...

HTH,

GP

1000base-sx ws-g5484. i checked the cisco web site. but the fibre not sure whether is exactly fit the switch. only knew it is a multi-mode fibre. however, i can tell more detail about this, when i connect the two switch with the fibre(2900XL and 3550)from the beginning no light of the two switchs. but after i type the command in the 3550 "speed nonogetiation" the light of 2900XL is on. does it mean i can send the command to 2900XL through the fibre? no other cable connection between these two switchs except the fibre.

pls help and thanks very much

paul nazgulero =E5=AF=AB=E9=81=93=EF=BC=9A

If it's SX or LH/LX GBIC, you can use a fiber patch cord to "loop" your TX to RX ports, and you should get a light. It will check GBIC itself.

Do you have matching GBICs on your 3550 and 2900 (i.e. both are SX)? If you have old 2900XL with integrated fiber port, it may be 100BaseF port, not gigabit, and the light may come with just a fact that the port sees something (light form a neighbor). So, it may mean nothing.

How are you going to use this switch? Who will be connected to 3550 by the GBIC? Can you connect them instead of 2900XL?

Good luck,

Mike

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yes, it's ok after test the loopback of 3550. actually, i want to trunk these two swichs with the fibre though the 2900XL is 100BaseFX. i read the doc of 3550, as i remember i cannot change the negotiation of gbic. so it means i cannot put these two switch together by fibre connection? i think i may use back the cat5 for the purpose. anyway, thx all. thx for the reply.

paul CiscoHeadsetAdapter.com =E5=AF=AB=E9=81=93=EF=BC=9A

Paul,

I think you are on the rigfht track. According to Cisco 'you cannot configure speed or duplex mode on GBIC slots, but for certain types of GBICs, you can configure speed to not negotiate (nonegotiate) if connected to a device that does not support autonegotiation'. You indeed need a multimode fiber cable for your type of GBIC. The problem might also be with your configuration, can you post the GigabitEthernet configs from both sides ?

Regards,

Naz

Naz,

thanks for your reply. the config just erase it since i want the thing make it simple . but i only add the following lines to 3550 , and nothing in 2900XL side. the 2900XL led will be on. in 2900XL, when i want to apply the "negotiation auto " , the msg prompt "this command is not supported for Fa0/23(this is the fibre interface).

! interface GigabitEthernet0/1 switchport mode dynamic desirable speed nonegotiate ! interface GigabitEthernet0/2 switchport mode dynamic desirable speed nonegotiate ! interface Vlan1 ip address 192.168.1.1 255.255.255.0 shutdown the IOS of the 3550 is just upgrade to EMI(12.1(22)EA4) something. and the 2900XL is 12.0(5)WC7

because now is late night. if the info above is not enough. i can try to find the old config to post. thanks very much.

paul

nazgulero =E5=AF=AB=E9=81=93=EF=BC=9A

Hi Paul,

You can not mix and match between 100BaseFX and GBIC. It's different technologies.

Sincerely,

Mike

paul CiscoHeadsetAdapter.com ???