Re: [Softwires] MAP draft 11 question on fragment ID space reduction

[Ted Lemon <[e-mail]>]

On Oct 14, 2014, at 5:01 AM, Ole Troan <[e-mail]> wrote:
> splitting the fragment id space so that there is only a single bit per CPE sounds like a corner case that should be disallowed. I don't know if we have the knowledge to be able to specify exactly how much of the fragment id space is safe to split up though.is it 4, 6, or 8 bits?

There's a lot to think about here.  The fragment ID translation algorithm probably needs to maintain a cache so that it doesn't accidentally overload fragment IDs.   The set of all outstanding fragments has the potential to be larger than the set of all ports in use, so there is definitely reason to be concerned about shrinking the fragment ID space.   However, shrinking the fragment ID space _does_ serve the useful purpose of isolating fragment ID collisions to the nodes that are supposed to be receiving the fragments.

It may be that the right thing to do is to note that this is a problem, make a recommendation, but essentially leave it as future research, since we really haven't analyzed the problem in enough depth to make an informed recommendation.

> if changing back to SHOULD from the MUST would lead people to accept that we leave the exact recommendations for further study I would be happy to do that.

So yes, this might be a good way to go.