C3560 does not communicate with C3550 by fiber connection

[christophepealat]

I have a 3560 and 3550 Catalyst switches on version 12.2 IOS. I don't know why the fiber connection is not working:

C3550 configuration:

interface GigabitEthernet0/1
switchport trunk encapsulation dot1q
switchport mode trunk
no ip address
mls qos trust cos
auto qos voip trust
wrr-queue bandwidth 20 1 80 1
wrr-queue queue-limit 80 1 20 1
wrr-queue cos-map 1 0 1 2 4
wrr-queue cos-map 3 3 6 7
wrr-queue cos-map 4 5
priority-queue out

C3560 configuration:

interface GigabitEthernet0/1
switchport trunk encapsulation dot1q
switchport mode trunk
srr-queue bandwidth share 10 10 60 20
srr-queue bandwidth shape  10  0  0  0
queue-set 2
mls qos trust cos
auto qos voip trust

There is no traffic because the LED does not blink.

Please help.

Thanks,

Mat

[rtjensen4]

Are you using the correct / same SFPs / GBICs in the switches? Also, are you using the correct type of fiber Multimode vs. Singlemode.

Please post a show inventory from both switches so we can see which port adapters are in use.

Also, if the ports are dual-purpose (i.e. can be Copper OR SFP), make sure the interface has media-type sfp configured.

Another thing, make sure the ends of the fiber get swapped when you link the switches. You need the tx fiber on one switch to go to the rx port on the other. If you just connect the fibers without checking or swapping the ends, you won't get a link.

Hope to Help.

[christophepealat]

I was wrong, sorry, IOS version of 3550 is "12.1 (13) EA1a" while the other Switch (3560) is "12.2(25r)SEC"

The problem can come from there?

show inventory (3560):

NAME: "1", DESCR: "WS-C3560-48PS"
PID: WS-C3560-48PS-S   , VID: V04, SN: CAT1120ZLY5

NAME: "GigabitEthernet0/1", DESCR: "1000BaseSX SFP"
PID:                     , VID:    , SN: FNS12420JEL

NAME: "GigabitEthernet0/3", DESCR: "1000BaseSX SFP"
PID:                     , VID:    , SN: FNS12420JEG

This command was introduced only on version 12.2 IOS, I can not execute the command on the 3550 for the moment.

Thanks for your help.

Mat

[rtjensen4]

You can see what the model of the GBIC in the C3550 is just by pulling it out and looking on it. You don't need to bring the switch down for that or anything.

I would guess, assuming you have the right kind of fiber and matching GBIC/SFP, it would be a tx/rx fiber issue. if you connect one end of the fiber to one of the switches, you should see a light coming down one fiber (DO NOT SHINE IT IN YOUR EYES!!), connect that fiber to the other switch (GBIC/SFP) into the port that doesn't have a light.

The GBIC for the 3550 uses SC (Stick and click) connector. the two fibers on SC typically slide together, just take them apart and flip them around. I have not personally taken apart the LC connectors that connect to the SFP, so I can't tell you how to do it. I'd connect the fiber to the 3560 first then deal with flipping the fibers at the 3550.

Just my opinion of course.