SFP Problem with Cisco 3750-X

[john snow]

Hi, I have a Mikrotik CCR1036-12G-4S router which has 4 SFP ports to receive fiber. I receive the fiber on the sfp1 port and I have a switch (sw1) connected to several ethernet ports of my router. So far so good.

But I would use the sfp2 port to recover the fiber and use it in a second switch (sw2) and that's the problem: The sfp2 port LED remains fixed and the second switch (sw2) indicates no cable is connected.

The switch (sw2) is a Cisco Catalyst 3750-X, the network module for the Catalyst 3750-X is the C3KX-NM-10G and the sfp module used is SFP-10G-SR. Finally, the fiber cable is connected from sfp2 port to the second port (SFP+) of the network module. The sfp module is recognized (Te1/1/1) but indicates no cable connected (notconnect).

I think there is a configuration to be done between sfp1 and sfp2 ports but I do not know what to do.

Thank you in advance for your help.

[andrewswanson]

Hi

See https://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst3750x_3560x/hardware/install/notes/net_mod_note.html#wp129080 for C3KX-NM-10G combinations of SFP and SFP+ modules:

• Slots 1, 2, 3, and 4 with 1-Gigabit SFP modules
• Slots 1 and 2 with 1-Gigabit SFP modules and Slot 4 with one 10-Gigabit SFP+ module
• Slot 2 with one 10-Gigabit SFP+ module and Slots 3 and 4 with 1-Gigabit SFP modules
• Slot 2 and Slot 4 each with 10-Gigabit SFP+ modules

hth
Andy

[Reza Sharifi]

Hi,

CCR1036-12G-4S comes with 1Gig SFP. The optic you are trying to use on the 3750x (SFP-10G-SR)

is 10Gig.  So, one side is 1Gig and the other side is 10Gig?  If this is the case, that is not going to work unless you put a 1Gig SFP in the switch module. The optics speed needs to be the same.

HTH

[john snow]

Yes, but i use the same module on the router and the switch (sfp-10g-sr)