Some of you may remember about half a year - year ago, I asked for feedback (and got some) for an internet draft on MTU issues in the tunnels which are set up in the network. This is a topic with pretty high operational relevance.
I've revised the draft again based on some really good feedback, and it's getting very near publication soon.
So, I'd like to solicit more comments (on- or off-list). Please comment within about a week or so.
Tunneling techniques such as IP-in-IP when deployed in the middle of
the network, typically between routers, have certain issues regarding
how large packets can be handled: whether such packets would be
fragmented and reassembled (and how), whether Path MTU Discovery
would be used, or how this scenario could be operationally avoided.
This memo justifies why this is a common, non-trivial problem, and
goes on to describe the different solutions and their characteristics
at some length.