Cisco 2960 SFP <—> FMC setup

[nkbg]

I separate my home network from the audio network via a pair of FMCs and would love to eliminate one FMC and power supply but utilizing the SFP port on the 2960. 

 

Has anyone successfully connected the fiber output of a FMC to the uplink input of a Cisco 2960 switch with a SFP module?

 

Any help is appreciated!

 

 

[Iving]

On 11/16/2019 at 6:22 PM, plissken said:

Here is the promised part 3. Warts and all. You'll see me do some minor t-shooting as I decided not to edit it out. The third part isn't as important to what we were discussing in this thread but it does round it out a bit. 

 

 

tyvm

AS medal of honour

[jaynyc]

On 7/12/2019 at 9:17 AM, luisma said:

Just came across this post, best fiber setup would be using a switch with SFP modules and good shielding and stay away from individual FMC whenever possible, the GTEK specifically is not good at shielding EMI/RFI

@luisma   Can you elaborate about the GTEK FMC not shielding EMI/RFI well?  How does one determine this?  Is there a published spec or other measurement?

[luisma]

There is no spec and that is what's surprising. Basically you take a spectrum analyzer and you measure the RFI from the device and you get an idea on how good the shielding is

[jaynyc]

@luisma so did you measure it?  That’s what I’m trying to understand.... how do you know the shielding for EMI/RFI is poor?

[luisma]

Because I went into Amazon and bought a whole bunch of switches different brands and measured each one by one, some with sfps some without it some regular fiber some with single fiber to transmit receive (I forgot the term)

Just remembered WiDi

[Ricardo007]

On 11/8/2019 at 9:21 PM, Jud said:

The switch attached to the eero by Ethernet cable runs optical to a second 2960

Jud

Did you had to configure the Uplink SFP port as LAN port on the second Cisco switch?

[Jud]

3 hours ago, Ricardo007 said:

Jud

Did you had to configure the Uplink SFP port as LAN port on the second Cisco switch?

 

It was a long time ago, but I don't remember having to do that (or configure anything at all, just plugged in the units, and then when they were ready, the cables).

[bbosler]

just saw this, a few things

 

the idea that trapping RF and having it build up inside the case because it is wrapped in copper foil is just plain wrong.

 

adding a linear supply is indeed "trivial" at least for the 8 port units I have. It is a single 12V supply so hooking in a 12V linear supply is trivial if you can cut and splice a few wires.

 

I've replaced the  oscillators with TCXO and OCXO on several units and the person I did it for is very happy with the results. That isn't so trivial. he also liked using the optical ports. YMMV

[luisma]

5 minutes ago, bbosler said:

 

the idea that trapping RF and having it build up inside the case because it is wrapped in copper foil is just plain wrong.

The idea was to find out how much the copper foil attenuated (not block) that specific frequency (it works different for different frequencies), and it is directional in some cases.
And the application wasn't audio but something different where attenuation (for better isolation) was desired.

 

 

 

 

[bbosler]

On 11/7/2019 at 9:57 AM, Solid-State said:

do NOT Wrait with copper tape,

closing in the smal EMI/RFI that the switche produce is not good,

the radiation have to disappear somewhere.

otherwise it's building up more and more inside the switch,

 

I was commenting on this advice. RF will not build up more and more inside the device. 

[fmzip]

On 6/22/2019 at 12:45 PM, nkbg said:

Thank you everyone for your help. I was able to get the optical link up and running. I’ve listed the equipment for reference:

 

Switch

Cisco WS-C2960G-8TC-L

Link: Easy to find used ones on eBay for $30-$60, I have the Gigabit version

 

SFP

Cisco GLC-SX-MMD Compatible 1000BASE-SX SFP 850nm 550m DOM Transceiver Module

Link: https://www.fs.com/products/22138.html

 

FMC

Gigabit Ethernet Multi-Mode LC Fiber Media Converter (SFP SX Transceiver 

Included), up to 550M, 10/100/1000Base-Tx to 1000Base-SX

Link: https://www.amazon.com/dp/B0716XT1QT/ref=cm_sw_r_cp_tai_fFLdDbT94VD0P

 

Fiber

3 Meter Multimode Duplex Fiber Optic Cable (50/125) - LC to LC - Orange

Link: https://www.amazon.com/dp/B001B1JEW2/ref=cm_sw_r_cp_tai_jHLdDb3C0TRJB

 

Happy weekend!

Question,

 

Did you use just the one Cisco GLC-SX-MMD SFP in the switch and retained the use of the SFP that came with the FMC?

[fmzip]

On 1/17/2022 at 1:44 PM, fmzip said:

Question,

 

Did you use just the one Cisco GLC-SX-MMD SFP in the switch and retained the use of the SFP that came with the FMC?

I answered my own question.

 

The answer, purchase one Cisco GLC-SX-MMD SFP for the Cisco 2960.

 

And then I used one of these:

https://www.amazon.com/dp/B0716XT1QT?ref=ppx_yo2_dt_b_product_details&th=1

 

And one of these:

 

https://www.amazon.com/dp/B07PZKNYKS?psc=1&ref=ppx_yo2_dt_b_product_details

 

 

Plug and play, everything worked perfect. Added a linear power supply as well:

 

https://www.amazon.com/dp/B07T44S4MV?psc=1&ref=ppx_yo2_dt_b_product_details