In addition, Cisco offers a small range of STM-16 CWDM SFPs covering up to 80-90km (equals a powerbudget of 27dB) but CWDMs can do more than today´s 34dB.
I did some tests with high-powerbudget CWDM SFPs in an old 7.2.0 and came to the following conclusion: It is possible to operate Multirate (STM-1, STM-4, 1G Ethernet and STM-16) SFPs with powerbudgets over 34dB in an ONS plattform. First of all, the transceiver must be programmed correctly (don’t worry, this task is already done because we already prepared the templates on your behalf on reconfigure.me ). Secondly, all you are required to do is to slightly tweak the Alarm Profile of the ONS via the CTC because when you plug in a 34dB SFP, the laser will fire up to +5dBm. This is too much for the ONS management system. As a consequence,TX high power and high bias alarms will pop up.
If you want to get rid of these alarms follow these useful 5 steps:
Change Alarm Profile
- On the chassis´ main view, create a new alarm profile found under the Provisioning Tab
Provisioning -> Alarm Profiles, you can call it e.g. "CWDM"
- Change the attributes
PPM::HI-LASERBIAS and PPM::HI-TXPOWER from the value inherited to NA/NA
- Store the newly created profile on your ONS Node (click “Store”)
- From the “Alarm Behaviour” tab, select your linecard and select ´´CWDM´´Profile
(NOTICE: the profile is connected to all of the ports on this linecard)
- Finally click “apply” and the alarms based on “HI-TXPOWER” and “HI-LASERBIAS” will immediately disappear!
ONS-SI-2G-L2 (STM-16, 1550nm, 80km) SFP can have a TX level of -2dBm up to +3dBm compared to an ONS-SI-2G-S1 (STM-16, 1310nm, 10km) this is way lower – between -3dBm down to -10dBm.
If you look around in the CTC, you will find settings for optic thresholds (“Provisioning” -> “Optics Thresholds”). Changing these parameters´ relative values e.g. the deviation of the transmitting power level during operations compared to the initial power level when you started up this SFP! The following parameters can be changed within a range of 50% to 255%:
- LBC-LOW and LBC-HIGH (laser bias deviation)
- OPT-LOW and OPT-HIGH (Transmission deviation)
- OPR-LOW und OPR-HIGH (receive level deviation).
Nevertheless, having the ability to monitor and trigger alarms based on the deviation of a transceiver is very helpful – this allows you to easily identify changes or upcoming issues in your optical path.