SFP signal too strong

RouterOS General
1

We have a CCR1072 running 6.40.5 with an S+31DLC10D SFP module to communicate with our upstream proider.
Our upstream started getting receive errors over the last couple of weeks and its really climbing the last few days.

ON our side we see
Tx Power -4.483dBm
Rx Power -3.951dBM

Our upstream sees this
Tx -2.215dBm
Rx -0.175dBm

The Rx signal upstream is too strong.
This SFP module is design for 10KM but the run is in a building and probably less than 100m
I don’t see a single mode 10Gbps SFP module designed for shorter distances.

Is there a way to turn down the transmit power on the S+31DLC10D or can someone suggest a different SFP module to use?

2

There are attenuators on the market.
Just an example:
https://www.fs.com/c/optical-attenuators-1023?utm_source=bing&utm_medium=cpc&utm_campaign=04-A-EU&utm_term=%2Bfiber%20%2Battenuator&utm_content=%23GMK-A-NL%20Attenuators#matrix

3

“This SFP module is design for 10KM but the run is in a building and probably less than 100m
I don’t see a single mode 10Gbps SFP module designed for shorter distances.”

The transmission distance is less than 100m, then why not use LRM SFP+ module that support 220m?

Or you can take the advice of the guy above, try to use optical attenuators.

4

If texmeshtexas already has the 100m SM fiber in place, that could be a problem, since the module you mentioned is MM.
I have SM modules running on short MM OM4 fibers (10 m), but never tried the other way around (and this could be a problem because of the much smaller aperture on the SM fiber and the shorter wavelength).

5

Im using S-31DLC20D and thesee modules are SM for 20km and Im using them at 20meters, does it makes problem ?

Thanks.

6

For short range, you can use this Generic Compatible 10GBASE-LRM SFP+ 220m DOM Transceiver Module.
or use this optical attenuator to reduce the power level of an optical signal, either in free space or in an optical fiber.

7

Is it possible for the signal to gain power down the line, even if it is a short distance?

8

I’m afraid the explanation is as simple as the Rx value measured so far away from the operation range is not accurate, despite its resolution to 4 decimal places. Or even worse, the input may have been already fried by the excess input power.

9

Can’t you just use 2x1G SFP (not SFP+) MM fiber transceivers for this task?
SFP fiber transceivers are usually cheaper than RJ45 modules., SFP+ slots also accept SFP devices.

10

Start a new thread. This one here is for a different issue.

[quote=AlanWang post_id=662266 time=1526537790 user_id=121267]
I have a Chenbro 4U server with an older dual LGA 2011 (v1) Foxconn motherboard. It has 2x SFP + 10 Gb ports (1 ethernet port, but it’s for BMC). I also have a Cisco SG200-26 gigabit switch. As I’ve learned recently, you can’t connect a SFP+ 10Gb port (using an SFP+ cable) to a 1Gb SFP port. So my question is, would the following set work:



Use a GLC-T Cisco 1000BASE-T SFP Transceiver Module . Plus that into the SFP+ 10Gb port on my server. Then simply plug in a cat 6 cable to run from the transceiver to any open ethernet port on my switch?



Do you know of a better solution or a cheaper one? Or is this priced well and will work with no problems?
[/quote]