sfp-ignore-rx-los doesn't stick (and what exactly does it do?)

RouterOS General
1

I use a hEX S with a GPON SFP (which has its own OS, IP address and management interface). When no fiber is connected, RouterOS doesn’t allow accessing the SFP’s web interface:

> /interface/ethernet/monitor sfp1
                        ;;; GPON SFP ONT
                      name: sfp1
                    status: no-link
          auto-negotiation: done
                 supported: 10M-baseT-half,10M-baseT-full,100M-baseT-half,100M-baseT-full,1G-baseT-half,1G-baseT-full
               advertising: 10M-baseT-half,10M-baseT-full,100M-baseT-half,100M-baseT-full,1G-baseT-half,1G-baseT-full
  link-partner-advertising: 10M-baseT-half,10M-baseT-full,100M-baseT-half
        sfp-module-present: yes
               sfp-rx-loss: yes
                  sfp-type: SFP/SFP+/SFP28/SFP56
        sfp-connector-type: SC
        sfp-link-length-sm: 20km
           sfp-vendor-name: ZYXEL
    sfp-vendor-part-number: PMG3000-D20B
       sfp-vendor-revision: V1.0
         sfp-vendor-serial: S[REDACTED]
    sfp-manufacturing-date: 15-05-25
            sfp-wavelength: 1310nm
           sfp-temperature: 52C
        sfp-supply-voltage: 3.3V
       sfp-tx-bias-current: 24mA
              sfp-tx-power: 3.01dBm

RouterOS 7.15 introduces the new setting sfp-ignore-rx-los. Is it supposed to fix this issue? I tried to enable it, but it doesn’t stick:

> /interface/ethernet/set sfp1 sfp-ignore-rx-los=yes
> /interface/ethernet/get sfp1 sfp-ignore-rx-los
>

Cheers
Maurice

2

With my experiments with ATT SFP module, I found that get command doesn’t work:

/interface/ethernet/get sfp-sfpplus1 sfp-ignore-rx-los

I found that only set and edit works, and works, as expected:

/interface/ethernet/set sfp-sfpplus1 sfp-ignore-rx-los=yes

/interface/ethernet/edit sfp-sfpplus1                   
value-name: sfp-ignore-rx-los

Looks like a bug.
I’m using RouterOS 7.16

3

It’s not bug, it’s how get works. Like this:

:put [ /interface/ethernet/get sfp-sfpplus1 sfp-ignore-rx-los ]
4

Did anyone figure this out? I’m now on the latest Router OS 7.18 and the SFP option to ignore RX LOS doesn’t Save/Apply for me either. My interface is kept as default name: sfp1. No matter how many times I tried to APPLY/OK and refresh the page, the modification is ignored.

5

sfp-ignore-rx-los doesn’t work on the hEX S, support confirmed that to me a few months ago. They’re looking into it.

6

Thanks @mauricew. Can you please link me to that forum thread so I can follow this fix? I’ve been trying to work around this Hex S issue in Router OS terminal without success either. Am eager for the OS update with the bug fix.

7

I don’t think there’s a forum thread (other than this one). I reported a bug through the support portal.
If you want to contact support yourself, you can reference my ticket # SUP-162428.
Support responded in August 2024 and confirmed that they were able to replicate the issue. I haven’t heard back from them ever since.

8

Hi @MauriceW - confirming I've since submitted a new bug ticket for the Hex S (SUP-181536). In my ticket I referenced your previous support ticket ID from August 2024. Please advise if you hear anything on this and I will do the same. Perhaps Mikrotik devs will reply here for others encountering this.

9

@MauriceW it’s been a while. Do you know whether this feature has been implemented yet in any new firmware update?

10

Unfortunately not as of 7.20beta4. I still have an open ticket regarding this issue.

11

@MauriceW I’ve just received an email from Mikrotik support indicating this issue has been fixed and will soon be released. Though I’m unclear as to which version will have the fix.

12

@miles267 Yes, I’ve received that (automated) message, too (on Thursday actually).

It’s not fixed yet in 7.22beta6, I’ve tested that. Maybe in the next development version, we’ll see.

13

According to the 7.22rc1 changelog, this was fixed for the hEX PoE:

*) sfp - fixed sfp-ignore-rx-loss parameter for RB960PGS;

But no mention of the hEX S, and I don't see a change in behavior.

14

@MauriceW agreed. Wish MikroTik wouldn’t have closed my support ticket for the hex S. This SFP-IGNORE-RX-LOSS has not yet been fully addressed.

15

Yesterday, I received another automated message about the issue having been fixed. It's not fixed in 7.22rc2, but maybe 7.22rc3, we’ll see.

16

It appears they finally fixed this in 7.22rc3 (despite not being mentioned in the changelog).

At least the setting does stick now. Haven't tested whether the interface actually stays up when disconnecting the fiber, can't do that right now.

17

@miles267 Did you get a chance to test 7.22rc3 yourself?

18

Hi @MauriceW no, unfortunately I’ve been unable to test this with my Hex S. When I saw that it wasn’t previously released for that hardware, I stopped. I could potentially dig out this hEX device and update to this test firmware if needed. I had stopped using it due to a specific need for this feature.

19

Okay, so I’ll mark this as solved since the setting can be applied now:

> /interface/ethernet/set sfp1 sfp-ignore-rx-los=yes
> /interface/ethernet/print where name=sfp1 proplist=sfp-ignore-rx-los 
Flags: R - RUNNING
Columns: SFP-IGNORE-RX-LOS
#   SFP-IGNORE-RX-LOS
;;; GPON ONT
5 R yes
> /interface/ethernet/monitor sfp1 once proplist=sfp-rx-loss  
           ;;; GPON ONT
  sfp-rx-loss: no

Whether it actually works I’ll see if the GPON connection ever drops.