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]

"Adjusting the TCP MSS won't affect this traffic as this is a multicast UDP stream."

Yup, fully agree.  However, possibly still very relevant for TCP traffic using the EasyVPN IPSec tunnel.  I.e. not needed on the GRE tunnel only transporting the multicast video.  NB:  Although unneeded on the GRE tunnel, using the command wouldn't be detrimental and would be good for any TCP traffic that might later use that tunnel.

[KGrev]

@Joseph W. Doherty  @Torbjørn  @MHM Cisco World  @Giuseppe Larosa  @Georg Pauwen 

Team, I have what I think may be an important update. I brought the cellular router inside and connected it directly to the office switch. Configured an interface as an interconnect and disabled the cellular, adjusted the acls and added some static routes and I'm back to where I was.  Meaning, The only pim interface on the cellular router is still my tunnel, the tunnel comes up with the correct routing, and the video looks exactly the same. That is with cellular fully disabled and using a physical connection. Of note, I can add pim to my connecting interface and the multicast will sidestep the tunnel and look perfectly fine.

So to repeat, using the same tunnel over a physically connected link yields the same poor video quality. So my cellular link appears to not have been an issue.

Do you agree? Am I looking at this correctly?