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

Fri May 23 16:24:52 EDT 2008

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> 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> 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> 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> 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> 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> 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> 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> http://www.audiocodes.com/objects/sbc/nCite_4000.pdf 

Nextpoint

Y

Y

Y

 <http://www.nextpointnetworks.com/files/NextPoint_SBC_USLTR_2008_hirez.pdf> http://www.nextpointnetworks.com/files/NextPoint_SBC_USLTR_2008_hirez.pdf 

Acme Packet

Y

Y

Y

 <http://www.acmepacket.com/html/page.asp?PageID=%7b06E4AEBC-24E2-46CC-BA95-7C74288FA45B%7d> 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> 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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