RE: UDP encaps for SCTP and SCCP

[<[e-mail]>]

That's hardly integrated into a shipping IP stack.

FreeBSD may be an SCTP reference implementation, but that's not significant deployment.

-----Original Message-----
From: Michael Tüxen [mailto:[e-mail]] 
Sent: 27 April 2010 19:16
To: Wood L Dr (Electronic Eng)
Cc: [e-mail]; [e-mail]; [e-mail]; [e-mail]
Subject: Re: UDP encaps for SCTP and SCCP

On Apr 26, 2010, at 10:34 PM, <[e-mail]> <[e-mail]> wrote:

> 
> On 26 Apr 2010, at 20:07, Jukka Manner wrote:
> 
>> Hi Lloyd,
>> 
>> I have to object here. :)
>> 
>> On 22.4.2010 13:50, [e-mail] wrote:
>> 
>>> The GUT draft and recreating IP packets strikes me as problematic in implementation, just as much as NATs. I'd rather have a simple IP-in-IP-tunnel (or even GRE) and rely on decap at the endpoints...
>>> 
>> 
>> GUT is not problematic, nor difficult. We have it running on Linux 
>> and works great. Next we'll put it on BSD (should be just a medium 
>> update to the code). I'm hoping to release the implementation as open 
>> source sometime in the future.
>> 
>> Our draft could be much better in explaining the idea clearly. The 
>> fact that we are "creating ip packets" is due to our implementation 
>> being a separate piece of code, a separate service on the OS, easily installed.
> 
> No. You are "_re_creating IP packets" in that you are not carrying the 
> IP header end-to-end, but are carrying minimal state to recreate an 
> approximation of the original IP header. That makes me nervous. (This 
> is not link header compression.)
> 
> You are not encapsulating the IP protocol header, but eviscerating it. You call that "reconstruct the native IP packet" or "rebuild the IP packet".
> 
> http://tools.ietf.org/html/draft-manner-tsvwg-gut-01
> (can I suggest a spelling checker for the typos?)
> 
> The summary benefits you state in section 8 work for a normal UDP tunnel, and with rather less complexity.
> 
> On a related note, I spent years dealing with proponents of SCTP, and yet never encountered any actual we-chose-to-use-SCTP end users. So, are there any actual DCCP users out there?
> 
> All this effort to save a few bytes tunnelling complex protocols that still won't be used? Pointless.
> 
>> The functionality could be as well be integrated into the IP stack, 
>> but that would be somewhat more challenging.
> 
> ...and won't happen.
The SCTP/UDP encapsulation is implemented in FreeBSD and part of the SCTP kernel implementation for Mac OS X.

Best regards
Michael 
> 
> L.
> 
>> 
>> regards,
>> Jukka
> 
> Lloyd Wood
> [e-mail]
> http://sat-net.com/L.Wood
> 
> 
> 
>