PTP Boundary clock not working when IGMP is enabled in bridge

RouterOS General
1

Hello,

When we enable the PTP Boundary clock, the clock is not locking to our GM (with the right PTP Domain & profile : smpte)
After some troubleshooting it seems that when we disable the IGMP Snooping in the bridge, the PTP is correctly locking to our GM…
But dealing with huge multicast traffic (video SMPTE2110) disabling IGMP Snooping is not what we’d like to do…

I found someone who seems to have a similar behaviour on this post regarding the 7.14rc

Is there something we are missing to have both PTP BC working & IGMP enabled ?

I already opened a support ticket
We are using the last 7.17b2

Kind regards

Kind regards

2

The problem is that IGMP snooping in ROS (as well as many other vendors) is shitty. A few years ago, when I tried, IGMP snooping on both ROS and Dlink effectively blocked IPv6.

And PTP works using multicasts.

So IMO it’s a bug in IGMP snooping in ROS. So nothing we, forum members, can help you with. The best way forward is to open trouble ticket with MT support and telling them about your problem. Hopefully they’ll fix the IGMP snooping so it won’t mess with everything, but only with some traffic (which needs that attention).

3

I found a workaround
I will update the ticket…

When IGMP is enabled, the dynamic MDB Entry 224.0.1.129 (the Multicast group related to PTP) does not include the bridge…
I tried to make a static MDB entry, including all my ports related to PTP and include the bridge. Bingo.. the PTP BC is locking to my GM and correctly acts as BC for my slaves devices… with IGMP enabled.

4

just wanted to say thank you this work around worked for me too!

5

Just for information, are you using MikroTik switchs for SMPTE2110 broadcast networking ?
Looking to share experiences because I’m doing some labs on it.
Regards

6

I’m still working on ST2110 in my labs too
I follow your workaronund and everything on clock is ok but…I have SDP error

I have configured 2 bridges and every bridge has One Ethernet Port
Both of them are /30
Unicast routing is ok
IGMP configured on every bridge (v3)
PIM-SM configured. Instance have bridges and eths
RP is configured and working
I have configured also SSM Range

In the PIM-SM tables I can see Joins but I have SDP error on device
I checked SDP and they are correct
(I have correct GM and so on…)

If I disable IGMP SDP is subscribed but PTP, obviously, drift.
Is There anyone that testing successfully?
Do I miss something?

To be honest it’s the first time with AoIP with /30

Model CRS326

Thanks in advance