Hi Lars, Well, I like option 1. I feel that option 2 is a chimera. The 'G' in the GUT proposal stands for "generic", but it is not entirely generic. The decapsulation stage is specific to the encapsulated protocol. The GUT draft gives one decap rule that is more-or-less suitable for TCP and DCCP. It doesn't work for SCTP. You have to look in detail at the encapsulated protocols to see if a proposed decap works. With my non-detail understanding of TCP, it looks like it works, but we'll need someone to look at that in detail. For DCCP, the proposed decap makes partial checksums ineffective. I think it's OK to do that, but you need to state that explicitly in the draft, and probably offer guidance on how to deal with partial checksum feature negotiation. You also need to deal with how to signal the use of UDP encap, and the other things included in my draft. Once you've done that, you have my draft. GUT has similar issues for SCTP. SCTP uses a CRC checksum that doesn't include the IP addresses, so the proposed GUT decap doesn't work for it. What's needed is actually easier to do. I don't know enough about SCTP to know what else needs to be done. As I've stated before, if you really think through a generic approach, it becomes an overall scheme that can be used by all protocols, plus a set of protocol-specific adaptations. That's where we're at with the DCCP- and SCTP-specific drafts. Tom P. > -----Original Message----- > From: tsv-area-bounces@xxxxxxxx [mailto:tsv-area-bounces@xxxxxxxx] On > Behalf Of Lars Eggert > Sent: Tuesday, May 18, 2010 3:38 AM > To: tsvwg@xxxxxxxx > Cc: DCCP working group; TSV Area > Subject: Re: UDP encaps for SCTP and SCCP > > Hi, > > the discussion has touched on lots of things related to UDP encaps, but I > haven't seen anything I'd call consensus on the question below. I'd > therefore like to ask folks to specifically state which option they > support: > > (1) do one SCTP-specific and one DCCP-specific UDP encaps > (2) do one generic UDP encaps that can be used with both > (3) do neither (don't do any sort of UDP encaps for SCTP and DCCP) > > Thanks, > Lars > > On 2010-4-22, at 12:57, Eggert Lars (Nokia-NRC/Espoo) wrote: > > Hi, > > > > as most of you probably know, there are two different proposals for how > to encapsulate SCTP and DCCP inside UDP. > > > > One approach proposes two protocol-specific encapsulation schemes > (described in draft-tuexen-sctp-udp-encaps and draft-ietf-dccp-udpencap). > > > > The second approach proposes a generic encapsulation scheme that can be > applied to both SCTP and DCCP (draft-manner-tsvwg-gut). > > > > As a community, we do need to come to consensus on which of these two > approaches we want to follow when it comes to UDP encapsulation of SCTP > and DCCP. I believe it would be very confusing if we were to standardize > both approaches. > > > > I'd hence like to ask folks to read the three documents and post their > views to the tsvwg@xxxxxxxx list. I'm personally especially interested in > hearing from folks who aren't on the author lists of the documents, but > obviously, the authors expert opinions do matter. > > > > Thanks, > > Lars > > > > PS: I'm pushing on this topic, because UDP encapsulation is the last > remaining work item in the DCCP working group before it can close...
