1Gb SFP failing in SPF+ slots

Hardware MikroTik hardware general
1

You’ll have to forgive me if this has already been answered as I haven’t found anything similar in searching… Has anyone else experienced 1Gb SFPs failing to properly link after fiber bounces when placed in SFP+ cages? Docs indicate the SPF+ cage supports both 1.25G and 10G SPFs, but I can repeatably lockup the link on Mikrotik routers with a simple fiber unplug/replug (CCR1009-8G-1S-1S+ and CCR1036-8G-2S+ tested). Hardware does not seem to make any difference a the port must be disabled/enabled in ROS for the port to become usable again.

Tested with CCR1009-8G-1S-1S+ and CCR1036-8G-2S+ routers utilizing Mikrotik, Planet, and Finistar 1.25Gb 850nm SFPs in various combinations and ports, as well as a Planet IGS-1020MT as an intermediary switch. Tested over multiple ROS 6.34.3 - 6.41.4 with FW 3.33 ad 3.41.

  1. CCR1036 SPF+ cage (either of the 2), 1Gb SFP module connected to 1Gb SPF in Planet switch with 1m fiber patch - links as expected, RX -5db to -7db on each side depending on vendor SFP module, passes traffic normally.
  2. Pull fiber patch and replug - Planet switch still shows RX -5db but will not link, CCR10xx shows link in ROS and on front LED, but SPF reports either -5db or -27db ( or -40db, no RX equivalent depending on SFP sensitivity) at different times, unable to characterize why it is sometimes one or the other.
  3. Pull SFP module out of CCR10xx SFP+ cage and reseat or replace with different SPF module - Planet switch shows -5db but will not link, CCR10xx shows link but still dead.
  4. Reboot Planet switch, reseat/replace hardware - no change in link status.
  5. Disable/enable the sfp-sfpplus interface in ROS - fiber links on both ends and passes traffic normally.
  6. Using regular SFP slot in CCR1009-8G-1S-1S+ or CCR1009-7G-1C-PC connected with same SFPs and fiber to the Planet switch - no issues removing/replugging fiber patch, links as expected every time.

Also, 1Gb SFP in CCR10xx SFP+ cage, will not link under any circumstance to a SFP in a 1Gb SFP cage of another CCR10xx.

Seems like an interface reset issue with SPF+ cages on Mikrotik routers. Anyone see this or is there a FAQ somewhere that explains this?

2

try to force 1G connection at interface.

3

disabling autonego (i reckon it’s needed to manually set the speed) is not really a good idea.

4

Have you tried to use another fiber? I’ve had problems with brand new fiber cords already, where for some reason they atenuate randomly. Check the temperatures and voltages on the doors too.

5

  1. I had not thought about hard setting speeds, as I guess as it’s a single speed SFP anyways… but I can give that a try. I was also going to do some more tests with singlemode SFPs as well, but hadn’t gotten that far as of yet.

  2. Tried with different fiber patch cords and RX levels do not indicate significant light loss. Also test using the same patch cord, in the same SFP, in multiple routers/switches/ports, works fine in a 1Gb SFP, just not in the 1/10Gb SFP+ cages. Voltages reported by SFPs were all nominal 3.3V and steady +/- a few mV.