[SIPForum-discussion] Can SIP Layer handle Fragmentation

[Zhou, Tong]

Has anyone compared the performance of SIP over UDP with fragmentation
and SIP over TCP in terms of reliability, session setup delay and cost
of computing resources in lab or production? - Tong

 

________________________________

From: discussion-bounces at sipforum.org
[mailto:discussion-bounces at sipforum.org] On Behalf Of mohab emara
Sent: Friday, September 12, 2008 3:21 PM
To: usman chaudhry
Cc: Stewart Bunce; discussion at sipforum.org
Subject: Re: [SIPForum-discussion] Can SIP Layer handle Fragmentation

 

Hello Usman,

Section 18 of the RFC3261 discuss this issue from clients and Server
perspective, and bottom line if the message MTU size is bigger than the
MTU size handled by UDP it should be sent via TCP.

 

And as you mentioned it is not SIP functionality as far as i know and as
you said.

Hope this helps.

 

Br,

Mohab



On Thu, Sep 11, 2008 at 9:35 AM, usman chaudhry
<usman_chaudhry at yahoo.com> wrote:

Hello Guys,

    It is my understanding that SIP (RFC 3261) cannot handle fragmented
packets. It is the responsibility of the lower layer protocols to do the
packet reassembly i.e. for SIP via UDP it will be the IP layer that
reassembles and for SIP via TCP it will be the the IP/TCP layer.
    
    Can you please confirm if there is any requirement on the SIP Stack
to reassemble fragmented SIP packets (i.e. Frames).

Regards 
Usman

 

----- Original Message ----
From: mohab emara <mohabemara at gmail.com>
To: Stewart Bunce <Stewart.Bunce at telsis.com>
Cc: usman chaudhry <usman_chaudhry at yahoo.com>; discussion at sipforum.org
Sent: Thursday, September 11, 2008 4:36:34 AM
Subject: Re: [SIPForum-discussion] Contact Header being changed by a SIP
Prxy.

Agree with Stewart, and find below the filtered data from table 2
concerning this point

Header field          where   proxy ACK BYE CAN INV OPT REG

      ___________________________________________________________

      Contact                 R            o   -   -   m   o   o

      Contact                1xx           -   -   -   o   -   -

      Contact                2xx           -   -   -   m   o   o

      Contact                3xx      d    -   o   -   o   o   o

      Contact                485           -   o   -   o   o   o



Where Bold d stands for delete only.

Br,
Mohab



On Wed, Sep 10, 2008 at 4:02 PM, Stewart Bunce
<Stewart.Bunce at telsis.com> wrote:

According to Table 2: Summary of header fields, A--O in RFC3261 a Proxy
can only modify the Contact header field in 3XX responses and even then
it is only allowed to delete it/them not modify.

 

Stew

	-----Original Message-----
	From: discussion-bounces at sipforum.org
[mailto:discussion-bounces at sipforum.org]On Behalf Of usman chaudhry
	Sent: 10 September 2008 10:41
	To: discussion at sipforum.org
	Subject: [SIPForum-discussion] Contact Header being changed by a
SIP Prxy.

	Hello All,
	
	    According to RFC 3261 is a SIP proxy allowed to change the
Contact Header for an INVITE
	
	regards
	Usman.

	 

 

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