[SIPForum-techwg] TCP vs. UDP (SP adoption of TCP?)

[Eric Burger]

Does anyone care what Asterisk supports?  If so, isn't the model that  
someone will contribute TCP support for their SIPconnect 1.1-compliant  
version?

On May 23, 2008, at 3:24 PM, Peter Dunkley wrote:

> Has your research found any information on the cost of these upgrades?
>
> If a customer has a choice between buying/using/connecting piece of  
> equipment X and Y, the only significant (to them) difference being  
> that to use X they will have to pay to replace or upgrade existing  
> piece of equipment Z, they will choose Y every time.
>
> Isn't Asterisk still UDP only?  This is in use as a PBX and Media  
> Server at many, many, Enterprises, and being free probably has a  
> larger install base than products from many of these vendors, and  
> being free is going to be difficult to get accurate numbers for.   
> Further, a large number of different bits of smaller vendors  
> equipment (if they were taken cummulatively) that only supported UDP  
> could have a larger total install base than products from one bigger  
> company.
>
> Some, more adventurous, service providers have developed their own  
> systems to do clever, bespoke, things.  Where will they get upgrades?
>
> I am not proposing that the recommendation be based just around the  
> capability of Asterisk - just pointing out that the table you have  
> provided is not comprehensive, it does not provide any indication of  
> the size of installed base (and what proportion may/do need  
> upgrades), and does not give any indication of likely upgrade costs.
>
> Depending upon how freely, easily, and cheaply, the upgrades are, it  
> is quite possible for the experiences of there still being a lot of  
> UDP only equipment out there could very well be correct.
>
> I have found myself on the end of a phone to customers and support  
> engineers with problems many times before, and the attitude from  
> them has almost always been:
> 	• I don't care what the specification says
> 	• I don't care that it is the other vendors equipment that is at  
> fault
> 	• This is costing me money/hassle
> 	• Fix it right now
> Please ensure that UDP will be supported by SIPconnect 1.1 devices  
> and that there is no possibility of anyone reading the specification  
> thinking that it is not.  Please ensure that there is no confusion,  
> and ensure backwards compatability, by either:
> 	• Explicitly mentioning that RFC 3261 compliance is mandatory.  Not  
> mentioning either TCP or UDP as MUST or MAY (as that is covered by  
> the RFC 3261 bit).  Indicating that TCP is the recommended default  
> (or mandating that a SIPconnect compliant device MUST attempt to use  
> TCP first before falling back to UDP).
> 	• or, Explicitly mentioning that RFC 3261 compliance is mandatory.   
> If you need to make TCP a MUST, make UDP a MUST too.  Indicate that  
> TCP is the recommended default (or mandating that a SIPconnect  
> compliant device MUST attempt to use TCP first before falling back  
> to UDP).
> If you mentioned one transport as a MUST and do not mention the  
> other at all (or only as a MAY) it is inevitable that someone,  
> somewhere, will assume that they do not need to use UDP at all.   
> Unless explictly indicated otherwise (in the same section of the  
> recommendation) they will ASSUME that the SIPconnect recommendation  
> overrides the RFC.
>
> I am all for avoiding interoperability issues, but my belief is that  
> there are more potential interop issues between SIPconnect and non- 
> SIPconnect devices than between just SIPconnect devices.  These are  
> the ones that will hurt the most - particularly if those devices are  
> old/unsupported/bespoke, and anyone who believes things can just be  
> upgraded is hopelessly optimistic.
>
> Peter
> -----Original Message-----
> From: techwg-bounces at sipforum.org [mailto:techwg- 
> bounces at sipforum.org]On Behalf Of Russell Bennett
> Sent: 23 May 2008 19:54
> To: techwg at sipforum.org
> Subject: Re: [SIPForum-techwg] TCP vs. UDP (SP adoption of TCP?)
>
> This has been a pretty long thread.  I think that almost everyone is  
> in agreement that both UDP and TCP are both required in SC1.1, with  
> a bias towards TCP as a REALLY MUST (or whatever language we choose)  
> and UDP for backwards compatibility.
>
> I just wanted to respond to one issue that has been raised several  
> times: that only UDP is supported by the majority of SIP deployments.
>
> I did some research on this and, while it is impossible to get data  
> on current installed base, I have been able to determine what would  
> be deployed today with existing product from the overwhelming  
> majority market share vendors.  Therefore, even if a customer had  
> older equipment from a given vendor that only supported UDP, they  
> have the option to upgrade to newer equipment that supports TCP or  
> TLS.
>
> So, the notion that anyone is somehow constrained from supporting  
> TCP (and even TLS) is invalid.
>
> Russell
>
> Vendor
> UDP
> TCP
> TLS
> Reference
> Microsoft
> N
> Y
> Y
> http://download.microsoft.com/download/d/b/6/db641148-427b-41d3-9f20-7ffbddaf65b8/OCS_VoIP_Guide.doc
> Cisco
> Y
> Y
> Y
> http://www.cisco.com/en/US/docs/ios/12_4t/12_4t11/FeatTLS.html#wp1092137
> IBM
> N
> Y
> Y
> http://download.boulder.ibm.com/ibmdl/pub/software/dw/lotus/sametime-sip.pdf
> Nortel
> Y
> Y
> Y
> http://www142.nortelnetworks.com/techdocs/CS1K_5_0/pdf/NN43001-564_01.05_NRS.pdf
> Avaya
> Y
> Y
> Y
> http://www.avaya.com/gcm/master-usa/en-us/products/offers/sip_enablement_services.htm&View=ProdTechSpec
> Alcatel-Lucent
> Y
> Y
> N
> http://www1.alcatel-lucent.com/doctypes/articlepaperlibrary/pdf/ATR2002Q4/T0212-SIP_Technology-EN.pdf
> Siemens
> Y
> Y
> Y
> http://www.enterprise-communications.siemens.com/Products/Phones%20Clients/Desktop%20Phones/ 
> ~/media/6DAA007008EB4A5CA0212A6D12A49770.ashx
> AudioCodes
> Y
> Y
> Y
> http://www.audiocodes.com/objects/sbc/nCite_4000.pdf
> Nextpoint
> Y
> Y
> Y
> http://www.nextpointnetworks.com/files/NextPoint_SBC_USLTR_2008_hirez.pdf
> Acme Packet
> Y
> Y
> Y
> http://www.acmepacket.com/html/page.asp?PageID={06E4AEBC-24E2-46CC- 
> BA95-7C74288FA45B}
> Covergence
> Y
> Y
> Y
> http://www.covergence.com/stuff/contentmgr/files/4adf40f79f81482fff714c46d8e06832/misc/ssesb.pdf
>
>
>
> -----Original Message-----
> From: techwg-bounces at sipforum.org [mailto:techwg- 
> bounces at sipforum.org] On Behalf Of Peter Dunkley
> Sent: Thursday, May 22, 2008 6:40 AM
> To: Eric Burger; techwg at sipforum.org
> Subject: Re: [SIPForum-techwg] TCP vs. UDP (SP adoption of TCP?)
>
> That would depend on whether you consider ISDN, and the like, to be  
> SIP related or not :-)
>
> On a more serious note there is a requirement for tunnelling UK-ISUP  
> within SIP messages.  Also, UK-ISUP has recently been extended to  
> allow BT-NUP messages to be tunnelled within - specifically so that  
> BT-NUP can be passed across a SIP network for legacy interworking.   
> This would result in SIP messages that can contain UK-ISUP messages,  
> that can contain BT-NUP messages, which may contain DPNSS messages...
>
> What you jokingly mentioned below is absolutely horrible - but  
> (within a national context) not as unlikely as it may seem!
>
> I have also heard of some interest in directly tunnelling DPNSS  
> within SIP as well.
>
> However, I would be the first to admit that BT-NUP and so on have no  
> place in a SIPconnect recommendation.
>
> Peter
>
> -----Original Message-----
> From: techwg-bounces at sipforum.org [mailto:techwg- 
> bounces at sipforum.org]On
> Behalf Of Eric Burger
> Sent: 22 May 2008 10:17
> To: techwg at sipforum.org
> Subject: Re: [SIPForum-techwg] TCP vs. UDP (SP adoption of TCP?)
>
>
> I would offer this philosophy would lead us to standardize SIPconnect
> 1.1 to use ISDN, possibly choosing Q.921, Q.sig, or BT-NUP :-)
>
> On May 21, 2008, at 10:24 AM, Peter Dunkley wrote:
>
> > In my opinion any recommendation needs to take into account not just
> > best practice, but actual practice.  Vilifying, or making life
> > difficult, for those who have pragmatically chosen something
> > different, and invested time and money in making it work, is not
> > going to contribute to the success of any recommendation.
>
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