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tbartim

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SFP Trunk will not come up on Cisco 2960 switch

Trying to connect fiber from a 3750 to 2960 cisco devive and the 2960 trunk port never comes up not eevn with the no shutdown command

Here is trunk config on the 2960

nterface GigabitEthernet1/0/49
 description Uplink to Core 3750
 switchport trunk native vlan 98
 switchport mode trunk
 srr-queue bandwidth share 10 10 60 20
 queue-set 2
 priority-queue out
 mls qos trust dscp
 auto qos voip trust
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Share-IT
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Not too sure on the network switches but i often get this on SAN switches when our datacenter boys use x-over fiber cables!

Is the fiber the right way round? look in the transciever and check you have light going to dark and vice versa.
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tbartim

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fiber cables are round
what cables are you using? thought they could only use LC cables which are made up of a pair.
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ASKER

LC Cables which is a pair
tbartim:
fiber cables are round


when you said that i though you meant you were using ST cables.

you can swap the left and right cables over. if they are "crossed" the link wont come up as you'll have TX to TX rather than TX to RX.

As i said, happens all the time at our DC with LC cables. I end up flipping the sides round (hurts your fingers) and all is well.

If that's not it and both transievers have light, the cables not broken and you've issued a "no shut" then no idea.

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yes Ive tried swapping (reversing the cables ) with no luck

The transciervers (SFP modules have no link lights lit on the 2960 but on the 3750 they are lit with a solid green
have you unplugged the fiber and looked inside the tranceiver on the 2960? you should see one side glowing red. if it's not then you probably have a duff/incompatible tranceiver. try swapping them between the switches. and see if they light then.
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koudry
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We Got the trunks going by turning off autonegotian and forcing full duplex on bothe the cisco 3750 and 2960

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"That's fantastic news. You must be very pleased.  These niggling things can be very frustrating"

Yes indeed I am thanks for everyones input
Bizarre that Auto-Neg broke it. Glad you got it working in the end though.