Hello Tom, Some more examples on how to negotiated DCCP-in-UDP in the presence of NATs would be surely helpful. For at least pointer to drafts and RFCs which describe how to use them. Just for the bunch of implementers out here, who might have to use this protocol. Having two protocols (or even more) to select during connection establishment would surely help to increase the reliability. For example, try first DCCP, then DCCP-UDP, then TCP - or any other order as negotiated with SDP. With best regards, Christian --------------------------------------------------------------- Dr.-Ing. Christian Hoene Interactive Communication Systems (ICS), University of Tübingen Sand 13, 72076 Tübingen, Germany, Phone +49 7071 2970532 http://www.net.uni-tuebingen.de/ -----Original Message----- From: dccp-bounces@xxxxxxxx [mailto:dccp-bounces@xxxxxxxx] On Behalf Of Phelan, Tom Sent: Wednesday, June 30, 2010 4:37 PM To: Colin Perkins; DCCP working group Subject: Re: I-D Action:draft-ietf-dccp-udpencap-01.txt Hi Colin, Hmm, the SDP is the way it is because I was trying to follow one of your earlier comments -- I thought not having a way to signal willingness to do both -STD and -UDP encap was a little problematic, but as I recall your comments you deliberately wanted it that way. My initial take on SDP allowed signaling either or both encaps, but you wanted to simplify things. If you'd like to rethink the SDP, by all means do. Tom P. > -----Original Message----- > From: dccp-bounces@xxxxxxxx [mailto:dccp-bounces@xxxxxxxx] On Behalf Of > Colin Perkins > Sent: Wednesday, June 30, 2010 5:13 AM > To: DCCP working group > Subject: Re: I-D Action:draft-ietf-dccp-udpencap-01.txt > > On 24 Jun 2010, at 20:15, Internet-Drafts@xxxxxxxx wrote: > > A New Internet-Draft is available from the on-line Internet-Drafts > > directories. > > This draft is a work item of the Datagram Congestion Control > > Protocol Working Group of the IETF. > > > > > > Title : Datagram Congestion Control Protocol (DCCP) > > Encapsulation in UDP for NAT Traversal (DCCP-UDP) > > Author(s) : T. Phelan > > Filename : draft-ietf-dccp-udpencap-01.txt > > Pages : 11 > > Date : 2010-06-24 > > > > This document specifies an alternative encapsulation of the Datagram > > Congestion Control Protocol (DCCP), referred to as DCCP-UDP. This > > encapsulation will allow DCCP to be carried through the current > > generation of Network Address Translation (NAT) middleboxes without > > modification of those middleboxes. > > > > A URL for this Internet-Draft is: > > http://www.ietf.org/internet-drafts/draft-ietf-dccp-udpencap-01.txt > > > The encapsulation looks fine to me, but I have some concerns about the > SDP signalling: > > In an SDP offer, how can I signal that I support both native DCCP and > DCCP-in-UDP? This doesn't seem to be possible using the "a=dccp-in- > udp" attribute, which "conveys no information about whether or not the > offerer is listening for DCCP-STD connections". > > How do I signal DCCP-in-UDP encapsulation in an ICE exchange? The ICE > "a=candidate:" lines in SDP use a transport protocol, not an attribute. > > I wonder if it would it make more sense to register transports such as > DCCP/UDP/RTP/AVP, rather than using an attribute, to try to solve > these issues? This is possibly something that should be raised in > MMUSIC. > > -- > Colin Perkins > http://csperkins.org/ > >
