Re: [Sip-implementors] May Proxy change From and To?

[Diego B]

Hi;
That is exactly what I was talking about.
A 3PCC can have B2BUA and Proxies capabilities, so embedding this two 
SIP element gives
full control of the legs.
But, if only proxy functionality is needed, a B2BUA is  overkilling, 
that is why I prefer to keep those two separately,
and do routing based on each call and routing rules.

Regards
Diego b
Jerry Ipe Thomas wrote:
Diego,
   In most real-world setups, a B2BUA implementation gives much more
   flexibility that a plain vanilla proxy. Yes, strictly speaking, a
proxy     
   *should not* change the host-port part of the SIP uri in the From/To

   headers. The end objective is to offer maximum flexibility while
keeping the
   intricacies of how that is achieved from the UAs hooked onto that
proxy.    
   Using a B2BUA, allows one to do *whatever* one wants apart from just

   proxying.
Warm Regards,
Jerry Ipe Thomas
Engineer (R&D)
D-Link India Ltd.
Software and R&D Center
#65, 35th Main
100 ft. Ring Road
2nd Stage, B.T.M Layout
Bangalore - 560068
PSTN: +91-80-26788350/1 Ext: 117
Cell: +91-9886442530
-----Original Message-----
From: Diego B [mailto:[EMAIL PROTECTED] 
Sent: Friday, April 15, 2005 1:51 PM
To: Jerry Ipe Thomas
Cc: 'Martin Koenig'; SIP Implementors Mailing List
Subject: Re: [Sip-implementors] May Proxy change From and To?

Hi;
I don't know which proxies are implemented as B2BUA, but in my opinion 
this is wrong.
A Proxy is a transactiona-engine, while a B2BUA is 2 SIP UAs wirking 
together for call control.
A Proxy is much more lighter that a B2BUA and, while is posible to mimic

a proxy with B2BUA,
one accidentally can cross the lines.
My company has a SIP Proxy server and also a B2BUA (  a SIP 3PCC 
Application Server ). And we keep those separatelly.
If we need a Proxy + call control we integrate both. But we keep the 
Proxy as a pure transactional engine
and the 3PCC as a pure call control engine.

Changing From and To will break compatibility with RFC2543.
I agree that one way to acomplish that is using a B2BUA:
UA1 ---------> Proxy ---- L1 ----> B2BUA ( change whatever ) -----------
L2 ----------> Proxy --------------> UA2
L1 = Leg 1
L2 = Leg 2
Proxy= cna be the same proxy or tow different proxies.
Regards
Diego B
Jerry Ipe Thomas wrote:
 

Martin,
  A lot of "proxies" are implemented as B2BUAs.
                       LOCAL "PROXY"
  [UA1]<----DIALOG_1---->[B2BUA]<----DIALOG_2---->[NEXT_ELEMENT]
  IMHO, this adds flexibility.
Warm Regards,
Jerry Ipe Thomas
Engineer (R&D)
D-Link India Ltd.
Software and R&D Center
#65, 35th Main
100 ft. Ring Road
2nd Stage, B.T.M Layout
Bangalore - 560068
PSTN: +91-80-26788350/1 Ext: 117
Cell: +91-9886442530
-----Original Message-----
From: 'Neelakantan Bala' [mailto:[EMAIL PROTECTED]
Sent: Thursday, April 14, 2005 12:19 AM
To: 'Martin Koenig'; sip-implementors@cs.columbia.edu
Subject: RE: [Sip-implementors] May Proxy change From and To?
See Section 16 of RFC 3261.  Proxy MUST NOT change the original SIP 
message it received from the UAs.  It can add few headers per the RFC.

Each of these steps is detailed below:
    1. Copy request
       The proxy starts with a copy of the received request.  The
   

copy
 

       MUST initially contain all of the header fields from the
       received request.  Fields not detailed in the processing
       described below MUST NOT be removed.  The copy SHOULD maintain
       the ordering of the header fields as in the received request.
       The proxy MUST NOT reorder field values with a common field
       name (See Section 7.3.1).  The proxy MUST NOT add to, modify,
       or remove the message body.
Thanks,
Neel.
-----Original Message-----
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of Martin 
Koenig
Sent: Wednesday, April 13, 2005 10:25 AM
To: sip-implementors@cs.columbia.edu
Subject: [Sip-implementors] May Proxy change From and To?

Hello,
in an RFC3261-compilant setup, is a SIP proxy allowed to alter the 
From-

and To-Header Field URIs?
According to my understanding, only From- and To-Tag are relevant for
transaction-matching, thus the URI should be changeable at will? Is
   

this
 

a correct assumption?
With best regards,
Martin Koenig
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