[SIPForum-techwg] TCP vs. UDP (actually, SIPconnect does *not* change SIP)

[Peter Dunkley]

What a SIPconnect device would do with UDP is allow non-SIPconnect, UDP 
only, devices to work with it.

This is important.  There are lots of UDP only devices in use right now 
(whether this is a good or bad thing doesn't matter - that's the way 
things are). 

Putting a service provider or enterprise in the position where, if they 
buy a new, tested, SIPconnect compliant device, it may not work with 
equipment they already have will just ensure that they do not care about 
SIPconnect.  If the customers don't care about SIPconnect neither will 
the vendors.

Full compliance to the parts of RFC 3261 that are relevant to the device 
type (UA, proxy, or whatever) must be mandatory.  That means both TCP 
and UDP as transports.

For me, as someone who will have to use the SIPconnect recommendation, 
that means that either transports shouldn't  be mentioned at all in the 
recommendation (forcing the reader to refer to the RFC), or the 
requirements of the RFC should be restated entirely.

I do not think there should be any wiggle room here.  UDP and TCP MUST 
both be supported.  The only RECOMMEND should be for which is the 
preferred transport - but as both are REQUIRED anyway that doesn't leave 
much scope for interoperability issues.  What the  RECOMMEND would do is 
start to nudge vendors towards using the preferred transport whenever 
possible.

Peter

Eric Burger wrote:
> Where I am coming from:
>
> *EVERY* MAY, SHOULD, RECOMMENDED, or other wiggle-word is begging for 
> non-interoperability.
>
> I would offer the document says, "MUST TCP" <period>.
>
> Saying "MUST TCP and MAY UDP" is the same as saying, "do whatever you 
> want, we don't care."
>
> I would offer a difference between a SIPconnect spec and an IETF spec 
> is WE CARE.
>
> *WHAT* would a *SIPconnect* device or service *DO* with UDP?  Connect 
> a lightbulb to the PSTN? (joking here)
>
>
> On May 17, 2008, at 7:14 PM, Peter Dunkley wrote:
>
>> I agree.  This was my concern when I read MUST TCP, but only MAY UDP 
>> in the document.
>>
>> I believe it is perfectly acceptable to say that SIPconnect compliant 
>> devices MUST support TCP, but there are a lot of UDP only devices in 
>> use within networks right now.  These need to keep working when 
>> connected with SIPconnect 1.1 compliant devices or no enterprise or 
>> service provider will have any interest in it.
>>
>> To my mind that means that both TCP and UDP are MUSTs.  But, perhaps 
>> TCP should be RECOMMENDed as the default transport (with UDP as a 
>> fall-back)?
>>
>> Regards,
>>
>> Peter
>>
>> Hadriel Kaplan wrote:
>>>> -----Original Message-----
>>>> From: techwg-bounces at sipforum.org 
>>>> [mailto:techwg-bounces at sipforum.org] On
>>>> Behalf Of Eric Burger
>>>> Sent: Friday, May 16, 2008 8:23 PM
>>>> To: techwg at sipforum.org
>>>> Subject: [SIPForum-techwg] TCP vs. UDP (actually, SIPconnect does 
>>>> *not*
>>>> change SIP)
>>>>
>>>> [as a participant]
>>>> UDP vs. TCP: SIPconnect can safely mandate *only* TCP.  If a device is
>>>> SIP (RFC 3261) compliant, it will support UDP, because RFC 3261
>>>> requires UDP support.  However, SIPconnect can feel free to MANDATE
>>>> TCP, as TCP support is a feature of SIP (RFC 3261).
>>>>
>>>
>>> I think that train of thought will be lost on people.  If they read 
>>> "MUST support TCP" in a sip-connect spec, and don't read "MUST also 
>>> support UDP", they will NOT then also assume UDP simply because 3261 
>>> says so.  Obviously we can't and shouldn't point out every single 
>>> requirement from 3261 we expect to be supported, but I think this 
>>> one passes the smell test. :)
>>>
>>> -hadriel
>>>
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>