09-21-2012 05:25 AM - edited 03-07-2019 09:00 AM
Hello All,
I have a problem with extending the LAN on a client site . They are looking to extend the LAN with a 2960S-series switch. Already in place is a 4510 switch which the 2960 is connected to via fibre. The 2 switches are both set up but there is no connectivity as I cant ping between them or anything.
The management VLAN on the 2960 shows line up, protocol down, which I believe means the VLAN is enabled but there is a form of physical mismtach on the ports. I have attached the configs of both switches. I would appreciate if anyone can take a look and help out with what might be wrong. I feel it might be a problem with GBIC module compatibility. The SFP installed on both ends of the switch are GLC-SX-MMD. On the 4510, the SFP sits in a twingig converter (CVR-X2-SFP) but there is no light on it at all when the cables are plugged in.
I need to be sure its not a configuration issue.
09-22-2012 07:45 AM
I have replicated the configuration in the lab with a 2950 as the access switch and a 3750 as a core switch and it works fine. This points to me that the config is ok (i stand corrected) and it must be something to do with physical connection. (maybe twin gig converters on core switch). My fear is splashing out on another twin gig converters as I initially thought it was a problem with SFP's got new ones and swapped them and it turned out it wasn't.
09-22-2012 07:52 AM
If your not getting link lights, its a layer 1 issue (if the ints are not shut). What type of fiber are you using and sfps?
Have you tried rolling the fiber at one end? Moving the tx and rx on one side.
09-22-2012 07:59 AM
Hi Jimmy, the SFP's are GLC-SX-MM, initially used GLC-SX-MMD, however checked a Cisco doc that didn't list the SFP as compatible with a twin gig converter(X2) so got the former as a replacement. Swapped cables and all but nothing.
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09-22-2012 08:09 AM
Not swapping the cables, but rolling the fiber, there is a difference.
Are they directly connected or go through a patch panel?
09-22-2012 08:12 AM
They go through a fibre patch panel but I have actually connected the devices directly eliminating the Fibre patch panel and still no connection.
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09-22-2012 08:20 AM
Ok, someone else will have to take the helm here as its Saturday morning and I am heading out to take the woman for her errands. They use the LC type connector and they were directly connected using the same cable, its not a rolling issue (or I have never seen this, normally that cable is rolled already. The cool thing about problems like this is learn so much along the way! I wish you luck.
09-22-2012 08:22 AM
Are you using a single mode or multi mode fiber patches?
09-22-2012 08:44 AM
Hi Dragos,
Its Mulitmode.
I will get new cables and try again on monday just in case.. The cables are LC-LC i believe. Will check and confirm.
Thank you so much for your help Dragos and Jimmy, its really appreciated. I am not that versed in fibre cabling but will get someone who is to help check.
09-25-2012 04:41 AM
Hi folks,
Just wanted to let you know the issue has been resolved by issuing
Switch(config)# hw-module module m port-group p
select gigabitethernet
this makes the supervisor engine use the gigabit Ethernet (if chosen) instead of the ten gigabit port.
Stumbled on this while going through some Cisco documentation. Also had to configure int gig5/3 & 4 instead of int tengig5/1( as configured original, see posted config)
Many thanks to Dragos, janko and jimmy. I appreciate your help.
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09-25-2012 04:56 AM
Hy Abayomi,
Thanks for the solution. i was really curious about the problem.
Best regards,
Dragos Tudor
09-25-2012 08:32 PM
Glad to hear, admittedly I would not of got the solution you arrived at, congrats and nice job!! Thanks for the update, I will file that solution away in the memory banks!
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