avoiding multicast fragmentation over tunnels
I am wondering if there is any help when it comes to multicast streaming over tunnels. How to avoid fragmentation of these packets. I am not talking about small packets like IGP control plane messages. It's about bigger packets that can get fragmented (like video streams, for instance). PMTUD and TCP MSS cannot help here because multicast is generally speaking always UDP or RTP.
The only thing that pops into my mind is to increase allowed frame sizes on the tunnel path, on the routers. Is there some way to do this, similar to using jumbo frames on switches? For instance, if I am using GRE tunnels I would need to boost MTU with 24 bytes on every interface on the path, but if I am using ethernet network I would need to tell that network to allow jumbo frames in the first place.
Anybody has experience on this, or ideas?