willing enough to use UDP-lite. BTW, I didn't say "change the encapsulation in some magic box in the network". I should hope that whatever encapculation is used would be used end to end.
My point is "do those functions once". On Apr 27, 2010, at 11:37 AM, <[email protected]> wrote: > Fred, > > advocating removing the interior protocol checksum across header and payload > (and reconstituting/recomputing it afterwards) violates end-to-endidness and > weakens the reliability guarantee. Bad idea. From a checksum perspective, > you'd do better saying 'use UDP lite with a minimal check just across its own > headers and pseudo-header' to decrease the computational overhead - that > should be a fixed value. > > Using a UDP (or lite) port to indicate what is being done here with a > particular weird encap, as well as the original ports on the interior packet, > is something that this approach is stuck with, I think. > > Lloyd Wood > http://sat-net.com/L.Wood > ________________________________________ > From: Fred Baker [[email protected]] > Sent: 27 April 2010 10:55 > To: Lars Eggert > Cc: [email protected]; [email protected]; [email protected]; tsvwg list; Wood > L Dr (Electronic Eng); Michael Welzl > Subject: Re: UDP encaps for SCTP and SCCP > > From my perspective, I would prefer to run a native encapsulation rather than > host it in UDP. If one wants a UDP encapsulation, I have no opinion on which > of the choices to make, but I would suggest a characteristic you want to > have. There is no point having UDP ports *and* SCTP/DCCP ports, and no point > in having a UDP checksum *and* an SCTP checksum. I would recommend removing > the duplicated functions from the interior protocol and relying on UDP's > counterpart, even if it is inferior, as it will be more readily deployed. > > On Apr 27, 2010, at 10:42 AM, Michael Welzl wrote: > >> Hi, >> >> Okay, I herewith speak up: yes I want to see UDP encapsulation for both >> these protocols >> (but right now I'm not sure which one). >> >> Both SCTP and DCCP are useful - if there was no consensus on that, ever, >> these >> groups would never have been formed, and the protocols would never have >> been developed. >> >> Now, they are not used much (on the Internet involving NATs); at least >> DCCP isn't. That's a problem. UDP encapsulation is a way to try to >> solve this problem - and saying that we shouldn't do this because the >> protocols aren't used is a bit stupid, isn't it? >> >> To repeat this more clearly and bluntly: >> >> tool X isn't working well => noone uses it. >> So let's not fix tool X because noone uses it anyway. >> Hmmm... >> >> Cheers, >> Michael >> >> >> On Apr 27, 2010, at 9:47 AM, Lars Eggert wrote: >> >>> Hi, >>> >>> please keep this discussion focused on which approach we should follow for >>> UDP-encapsulating DCCP and SCTP. >>> >>> I'm happy Lloyd posted his views. I'm hoping other community members will >>> speak up as well. If I were asked to characterize current consensus, I'd >>> probably say "disinterest for either approach." (Which would be fine, but >>> doesn't quite match the earlier feeling I got from the community, i.e., >>> that we do want UDP encaps for these protocols.) >>> >>> Lars >> > > http://www.ipinc.net/IPv4.GIF > http://www.ipinc.net/IPv4.GIF
