Poor multicast over Tunnel

[KGrev]

Hi,

I have a cellular router (IR809G) with a tunnel setup. I'm trying to view a multicast video over that tunnel. It does appear but the video quality is very poor. I'm in a great reception area and speed tests from the router into the network hover around ~50meg. The video file is 480p mp4. Other paths from the core router(rp) can view this feed fine but the path through the tunnel is the issue. Are there any requirements for a tunnel connection for multicast to flow properly? Ive attached some details from the spoke and core routers. I hope it is helpful.

Is it interesting that the tunnel does not show a DR for pim? My other pim interfaces on the router do show DR (they are removed from the text)

Thank you for any advice.

[Joseph W. Doherty]

Possible tunnel IP fragmentation?

[KGrev]

i was thinking so also but i believe the output shows I have the tunnel set to below what it actually is. I also tried useing path detection on the tunnel but go no change. I also tried changing my mtu on my VLC video feed source to 1000-1200. The client at the other end of the tunnel can see this change in wireshark.

[Joseph W. Doherty]

I believe, generally, video doesn't do PMTUD.

If you've doing WireShark at the tunnel end, that should show whether there's any fragmentation happening.

Fragmentation is just one common problem with tunnels, but as video is sensitive to network quality, there's many possible issues.

[KGrev]

@Joseph W. Doherty I attached two pictures from Wireshark. Do these look dire?

[Joseph W. Doherty]

Fyi: unable to view attachments, at the moment (technical issues). Might be several days before I can view them.

[KGrev]

@Joseph W. Dohertydoes this help?

[Joseph W. Doherty]

Yes, it does, thanks!

Unless I'm mistaken, appears there is fragmentation.

You did note you reduced MTU at video source?

[KGrev]

@Joseph W. Doherty I'll try to get another picture tomorrow, but if I reduce the mtu size of my video stream at the source, I can see the mtu size has lowered in Wireshark but I still see the fragment messages. I'll try to get another image tomorrow.

[KGrev]

@Joseph W. Dohertysorry it has taken me so long. I've been very sick. I'm back at the office today so I hope to reach back to you soon.

[KGrev]

@Joseph W. DohertyWhat sort of MTU would you suggest for the tunnel for this setup?

I think the interesting ports here would be:
Cell Router: -Cell0, Tunnel, VPN? Gig0

Internal router - tunnel 10 (outgoing interface is 1500.

[Joseph W. Doherty]

Largest that can transit, end-to-end, without being fragmented.

[KGrev]

@Joseph W. Dohertyso should I send "dont fragment" pings outside of the tunnel and find my largest mtu then go down from there?

[Joseph W. Doherty]

If you knew tunnel overhead, that might do.

You're unable to send DF tagged packet through tunnel?

[KGrev]

@Joseph W. DohertySorry i was thinking I should know what size I had to work with then adjust my tunnel to fit within that? Is that the wrong way to go about it?