[SIPForum-discussion] [Q] SIP/TCP vs SIP/UDP

[Broussard, Dan]

Use TCP when prack isn't available.

Dan Broussard
Level 3 

-----Original Message-----
From: discussion-bounces at sipforum.org
[mailto:discussion-bounces at sipforum.org] On Behalf Of Jonathan Rosenberg
Sent: Monday, March 13, 2006 10:53 AM
To: Sunny Xu
Cc: discussion at sipforum.org
Subject: Re: [SIPForum-discussion] [Q] SIP/TCP vs SIP/UDP

REGISTER is needed periodically regardless of whether the transport is
TCP or UDP.

Today, most implementations are still UDP, but the general move is
towards TCP. This is for several reasons, including NAT traversal, but
also because of increasing SIP message sizes.

The mechanisms for keeping connections open for dealing with NAT are
documented in:

http://www.ietf.org/internet-drafts/draft-ietf-sip-outbound-02.txt

-Jonathan R.

Sunny Xu wrote:

> In TCP, after the connection created, we don't need send REGISTER 
> periodically but only the first time. Because the TCP's keeping alive 
> mechanism is better than SIP's, I think so.
> 
> I think this is an advantage for SIP/TCP in some situation.
> 
>  
> 
> Sunny
> 
>  
> 
>  
> 
> ----------------------------------------------------------------------
> --
> 
> *From:* discussion-bounces at sipforum.org 
> [mailto:discussion-bounces at sipforum.org] *On Behalf Of *???
> *Sent:* Monday, March 13, 2006 6:44 PM
> *To:* discussion at sipforum.org
> *Subject:* [SIPForum-discussion] [Q] SIP/TCP vs SIP/UDP
> 
>  
> 
> Hi All,
> 
>  
> 
> I'm wondering if there's any reason to prefer SIP/UDP to SIP/TCP..
> 
>  
> 
> If a phone exists behind NAT/FW, it should send REGISTER periodically,

> I think.
> 
> In case of UDP, the phone just sends the REGISTER message without any 
> keeping up connection.
> 
> But in case of TCP, the phone should keep the TCP connection all the 
> time, in which I think there're
> 
> some unexpected problem.
> 
>  
> 
> Actually I should consider the deployment of SIP/TLS and SRTP,
> 
> and I seriously think over the possible problem that I don't know, 
> especially relating the NAT/FW.
> 
>  
> 
> If you have any comments about my difficulty, please let me know..
> 
>  
> 
> Thanks in advance..
> 
>  
> 
> Peter Kim
> 
> 
> ----------------------------------------------------------------------
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> 
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-- 
Jonathan D. Rosenberg, Ph.D.                   600 Lanidex Plaza
Cisco Fellow                                   Parsippany, NJ 07054-2711
Cisco Systems
jdrosen at cisco.com                              FAX:   (973) 952-5050
http://www.jdrosen.net                         PHONE: (973) 952-5000
http://www.cisco.com
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