Connecting 2 Cisco 3560 using GLC-SX-MM SFP, what cable should I use?

[cciewant2be]

Hi,

Should I use LC/PC to LC/PC MM diameter 2/2C/L 2meters fibre cable?

InsLoss 0.05dB

RetLoss 36.5dB

Thanks a lot!

Regards,

Ron

[spremkumar]

Hi

You can very well make use of LC/LC MM cable to patch up the SX MM SFPs installed in ur 3560 switches.

We have done up with patching our 3750s using the SX-MM SFPS and LC/LC MM fiber patch cords..

regds

[cciewant2be]

Hi,

I had tried with it. However, the LED and links doesn't goes up.

I was thinking either the SFPs or the fiber cable were faulty.

Regards,

Ron

[spremkumar]

Hi

can u try reversing the Rx/Tx pair at one side of the connection and check ??

regds

[cciewant2be]

Hi,

The fibre cable is fixed to the connector of the LC.

Therefore I can't twist it.

Thank you.

Regards,

Ron

[yasirirfan]

Hi Ron,

First to make sure your fiber cable is ok juist put a light at one end of the fiber and try to see the light at the other end, u can use a tourch. Also make sure the gigabit interface is not shutdown just go to the gigabit interface and type no shutdown, if u paste ur config for the swicth it would be more easier to figure out the problem

[cciewant2be]

Hi,

I had tried shut and no shut both the interface(gigabit) but still down.

I will test the fibre cable to see if problems lies on that or not.

Attached are the dump of the 2 switches.

Thank you.

Regards,

Ron

[yasirirfan]

Hi CCIE use following commands in ur gigabit interface

interface gigabit 0/1

switchport trunk encapsulation dot1q

switchport mode trunk

no shutdown

use same comands in other switch too.

Please check and let me know

Cheers

Yasir

[yasirirfan]

Hi Ron

Your fiber return loss is too much it should be less than 5 db so try to change the fiber cable too. Before changing check it the way i said u before.

cheers

Yasir

[cciewant2be]

Hi all,

Thanks for all the knowledge sharing.

I had verify that the cables are fine(Able to see light from one end to the other)and I also verify the pair are correctly placed. Meaning A to A, B to B, not vice versa.

I got 2 pairs of similar cable both working as tested in similar ways

The only thing is that it might be a wrong specification cable as what Yasir mentioned.

Thanks! I will try to get another piece of different specification cable.

Regards,

Ron

[cciewant2be]

Hi All,

Problem Resolved!

I notice the arrows indicated on the SFP and i swap the cables making 1A to 2B and 1B to 2A instead of the previous 1A to 2A and 1B to 2B.

How I do it? Took the risk of breaking the cables and took out 1 side of the fibre cable encasement on the LC connector from just 1 end and swap it. Fix it back and plug back to SFP.

Green LED shown! Console shows "01:10:28: %LINK-3-UPDOWN: Interface GigabitEthernet0/2, changed state to up" and "01:10:30: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet0/2, changed state to up"!

Great! I'm done!

Thanks a lot for all the suggestion and knowledge!

Regards,

Ron

[spremkumar]

Hi

Thatz the reason i did suggest to reverse the Tx/Rx pair which will solve in most of the cases..

regds