Re: [Sip-implementors] Few offer/answer queries

2008-10-02 Thread Kamalakanta Palei (kpalei)
 
>What is the behavior of the receiver if it receives offer with 
>different
"session id" in
>re-INVITE or UPDATE?

Take down the call as REINVITE o-line with a new session id identifies a
session that does not exist at UA.

[Kamal]
Taking down the existing call may not be a good idea, one can reject the
request that contains changed SDP session-id.
Instead the re-INVITE or UPDATE should be rejected.  

Kamal
Cisco, Bangalore
India

-Original Message-
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of
Harsha. R
Sent: Tuesday, September 30, 2008 4:06 PM
To: Vikram Chhibber
Cc: sip-implementors@lists.cs.columbia.edu
Subject: Re: [Sip-implementors] Few offer/answer queries

Vikram,

Session id is kept constant across offers/answers sent by UAC/UAS. Only
Session version is incremented for every new offer/answer sent by
UAC/UAS.


The reason UA *MUST NOT* change session id can probably be inferred from
SDP RFC 4566, section 5.2

is a numeric string such that the tuple of ,
  , , , and  forms a
  globally unique identifier for the session.

Therefore by changing the session id, you are changing the identifier
for the session for either a UAC/UAS

To answer your specific questions.

>What is the behavior of the receiver if it receives offer with 
>different
"session id" in
>re-INVITE or UPDATE?

Take down the call as REINVITE o-line with a new session id identifies a
session that does not exist at UA.

>Also, what should be the behavior of the receiver if it receives offer 
>with same "session id" as previous but with version incremented more 
>than one?

IMO, a liberal implementation *SHOULD* allow this offer/answer to
proceed.
For me, this bears similarity
to the case when CSeq is incremented more than 1 for a subsequent
request from a UAC.

>b) We emphasize that UAS should send back its full capability offer in 
>response to offer-less re-INVITE. Does that also have "SDP session 
>resetting" effect in the sense that the answer SDP MAY not have same
"o"
>line session-id as sent by remote previously? This scenario comes when 
>you are trying to negotiate media-session with another entity within an

>established SIP dialog say network side call-transfer.

In this case of forced SDP offer, UAS must use the same session id in
the offer it sends, as it sent in a previous answer(in either 18X
response/200 OK INVITE), and increment the session version by 1.

Regards
Harsha

2008/9/30 Vikram Chhibber <[EMAIL PROTECTED]>

> Hi All,
>
>
>
> I have few queries on RFC 3264:   An Offer/Answer Model with the
Session
> Description Protocol (SDP):
>
>
>
> 8 Modifying the Session
>
> 
>
> When issuing an offer that modifies the session,
>
> the "o=" line of the new SDP MUST be identical to that in the
>
> previous SDP, except that the version in the origin field MUST
>
> increment by one from the previous SDP.
>
>
>
> The aforementioned statement defines the "o" line creation in the 
> offer by the sender.
>
>
>
> a)  Does this also mean that the receiver must always expect same 
> "session id" in all the subsequent offers after initial offer/answer? 
> What is the behavior of the receiver if it receives offer with
different "session id"
> in
> re-INVITE or UPDATE? Also, what should be the behavior of the receiver

> if it receives offer with same "session id" as previous but with 
> version incremented more than one?
>
> Are the above scenarios "legal" for UA or should it treat these 
> normally and continue by following philosophy of being strict while 
> sending and lenient while receiving?
>
>
>
> b) We emphasize that UAS should send back its full capability offer in

> response to offer-less re-INVITE. Does that also have "SDP session 
> resetting" effect in the sense that the answer SDP MAY not have same
"o"
> line session-id as sent by remote previously? This scenario comes when

> you are trying to negotiate media-session with another entity within 
> an established SIP dialog say network side call-transfer.
>
>
>
> Thanks,
>
> ~Vikram
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>



--
Regards
Harsha
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[Sip-implementors] SIPit registration closes tomorrow

2008-10-02 Thread Robert Sparks
(This is the last reminder - thanks everyone on these lists for being  
so patient with the crossposts).


Registration for SIPit 23 closes TOMORROW Friday October 3.

Please register immediately if you haven't already done so.

Links to the registration and more information can be found at
http://www.sipit.net
and
http://www.etsi.org/plugtests/SIPit/SIPit.htm

Thanks, and see you in Lannion week after next!

RjS


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Re: [Sip-implementors] Early dialogs, reliable responses and PRACK addressing

2008-10-02 Thread Dmitry Akindinov
Hello,

Iñaki Baz Castillo wrote:
> 2008/10/2, Dmitry Akindinov <[EMAIL PROTECTED]>:
>>> For me this means that, in RFC 3261, Contact must be present in a 2xx
>>> to an INVITE.
>>>
>>  Yes, but according to this table it's optional for 1xx. And 3262 does not
>> update that, though with reliable 1xx the Contact is more likely to be
>> needed to address the PRACK.
> 
> Yes, but RFc3261 updates the 1xx behaviour when it clearly says:
> 
> RFC 3262:
> --
> 
>  4 UAC Behavior
> 
>The provisional response ***MUST establish a dialog*** if one is not yet
>   created.
> ---
> 
> And note that for a dialog to be established it's needed a remote
> target (not the initial RURI).

Yes, this is exactly how we get the idea of SIP dialogs, including the 
early ones. And that's why we want to avoid programming workarounds in 
our code particularly for this situation - because we believe that a 1xx 
without the Contact URI but requesting reliable handling is wrong. It's 
also not right even when reliable handling is not requested, but that 
does not hit us that bad :-)

> So, it's true that RFC 3262 doesn't update the table, but note that
> "Contact" just would be required if the 1xx includes a "Require:
> 100rel",

That's something we kept saying to the vendor for several month already.

> so there is no need to update that table. In any case RFC
> 3262 could add:
> 
>  Header field  where   proxy ACK BYE CAN INV OPT REG
>  ___
>  Contact Ro   -   -   m   o   o
>  Contact1xx   -   -   -   o-   -
>  Contact 1xx + 100rel -   -   -   m   -   -
>  Contact2xx   -   -   -   m   o   o
>  Contact3xx d-   o   -   o   o   o
>  Contact485   -   o   -   o   o   o

It could, but it does not, unfortunately.

> Well, as you say life would be better if RFC 3262 says that, but
> however this is implicit by the above phrase "The provisional response
> ***MUST establish a dialog*** if one is not yet created".

Well, here we have a chain of reasoning (early dialog is created -> 
PRACK is sent within a dialog -> as an in-dialog request it should be 
addressed to RURI -> RURI should have been sent with 1xx -> RURI is 
required) versus the simple and short reference to tables in rfc3262 and 
3261 not marking the Contact header as required. And for some it's hard 
to follow these chains.

Thank you very much  for your comments. I've sent the link to the list 
archive with this discussion to the vendor. I hope this will move the 
scales and they fix their SIP implementation.

-- 
Best regards,
Dmitry Akindinov


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Re: [Sip-implementors] XML inside SIP

2008-10-02 Thread Victor Pascual Ávila
On Thu, Oct 2, 2008 at 12:39 PM, Manoj Priyankara (NOD)
<[EMAIL PROTECTED]> wrote:
> Does anyone know the usage of XML inside SIP messages (like NOTITY) ?

There are tens of RFCs registering new XML-based MIME types as well as
new XML namespaces.

This paper [1] might be what you are looking for, though.

[1] http://www1.cs.columbia.edu/~knarig/nyman.pdf
-- 
Victor Pascual Ávila

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Re: [Sip-implementors] sending DTMF as Notify

2008-10-02 Thread Paul Kyzivat
I'm not going to tell you how to do that because it isn't a legal sip usage.

It is true that some things have been known to use unsolicited NOTIFY. 
I'm not certain I have heard of it for DTMF, but I have heard of it for 
MWI. But its still not a standard usage.

The only plausible reason I can think of for you to want to do this is 
to interoperate with something that expects it. If that is your 
situation, then you need to defer to it regarding what it expects.

Thanks,
Paul

Vivek Gupta wrote:
> Hi,
> 
> I need information on how to send DTMF tones as unsolicited Notify method 
> within an established dialogue. Can anyone explain the 
> steps to implement the same?
> 
> Information on any SIP soft-phone that supports DTMF as Notify would be of 
> great of help?
> 
> With regards,
> Vivek GUpta
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Re: [Sip-implementors] Early dialogs, reliable responses and PRACK addressing

2008-10-02 Thread Paul Kyzivat


Harsha. R wrote:
> ... they just refer to the fact that Tables 1 and 2 in rfc3262 extend
> tables 2 and 3 in rfc3261 and the Contact is marked as optional in 1xx
> responses. If 3262 clearly stated that reliable provisional responses
> MUST have Contact - we would not have this issue
> 
> Its not clear to me as to why the 18X is expecting a Contact. The purpose of
> Contact is to do a target refresh.
> 18X missing a Contact header means a target refresh has not happened. In
> this case, address the PRACK to
> the original remote target( mostly the one used for  INVITE).

We have had to incorporate this behavior into some of our products in 
order to get them to interoperate with some broken implementations. But 
as Iñaki has already stated, this has many issues and is not conforming 
behavior.

Once the dialog has been established, with a target URI from a Contact, 
then you may omit the contact from future 1xxs if you wish.

Too much is being made of the tables. Several of the people who 
initially put those tables in now wish they had not. The tables are 
insufficient to cover all the nuances. You *must* read the text to get 
the details. Iñaki has already cited the various sections which, taken 
together, mean that you MUST include a Contact to establish a dialog.

Paul

> If all goes well, PRACK reaches the intended UAS and  call goes through;
> if not, UAS will retransmit 18X (missing contact header) and your UAC will
> keep sending
> PRACK to the latest remote target(mostly the one used in INVITE).
> After some time, UAS will take down the call on an implementation defined
> timer expiry for 18x
> 
> Regards
> Harsha
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Re: [Sip-implementors] XML inside SIP

2008-10-02 Thread Iñaki Baz Castillo
2008/10/2, Manoj Priyankara (NOD) <[EMAIL PROTECTED]>:
>
>
>  Hi All,
>
>  Does anyone know the usage of XML inside SIP messages (like NOTITY) ?

What is exactly the question?

-- 
Iñaki Baz Castillo
<[EMAIL PROTECTED]>

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Re: [Sip-implementors] Early dialogs, reliable responses and PRACK addressing

2008-10-02 Thread Iñaki Baz Castillo
2008/10/2, Dmitry Akindinov <[EMAIL PROTECTED]>:
> > For me this means that, in RFC 3261, Contact must be present in a 2xx
> > to an INVITE.
> >
>
>  Yes, but according to this table it's optional for 1xx. And 3262 does not
> update that, though with reliable 1xx the Contact is more likely to be
> needed to address the PRACK.

Yes, but RFc3261 updates the 1xx behaviour when it clearly says:

RFC 3262:
--

 4 UAC Behavior

   The provisional response ***MUST establish a dialog*** if one is not yet
  created.
---

And note that for a dialog to be established it's needed a remote
target (not the initial RURI).
So, it's true that RFC 3262 doesn't update the table, but note that
"Contact" just would be required if the 1xx includes a "Require:
100rel", so there is no need to update that table. In any case RFC
3262 could add:

 Header field  where   proxy ACK BYE CAN INV OPT REG
 ___
 Contact Ro   -   -   m   o   o
 Contact1xx   -   -   -   o-   -
 Contact 1xx + 100rel -   -   -   m   -   -
 Contact2xx   -   -   -   m   o   o
 Contact3xx d-   o   -   o   o   o
 Contact485   -   o   -   o   o   o

Well, as you say life would be better if RFC 3262 says that, but
however this is implicit by the above phrase "The provisional response
***MUST establish a dialog*** if one is not yet created".




-- 
Iñaki Baz Castillo
<[EMAIL PROTECTED]>

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Re: [Sip-implementors] Early dialogs, reliable responses and PRACK addressing

2008-10-02 Thread Dmitry Akindinov
Hello,

Iñaki Baz Castillo wrote:
> 2008/10/2, Dmitry Akindinov <[EMAIL PROTECTED]>:
> 
>>> RFC 3262 says clearly that "The provisional response ***MUST establish a
>> dialog*** if one is not yet created".
>>  ... they just refer to the fact that Tables 1 and 2 in rfc3262 extend
>> tables 2 and 3 in rfc3261 and the Contact is marked as optional in 1xx
>> responses. If 3262 clearly stated that reliable provisional responses MUST
>> have Contact - we would not have this issue.
>>  Yet, how simpler the life would be if rfc3262 (at least) stated clearly
>> that with reliable provisional responses the Contact header is required :-)
> 
> Are you sure of the meaning of that Table 1 in RFC 3262?
> 
> Note that RFC 3261 in table 2 says:
> 
>   Header field  where   proxy ACK BYE CAN INV OPT REG
>   ___
>   Contact Ro   -   -   m   o   o
>   Contact1xx   -   -   -   o   -   -
>   Contact2xx   -   -   -   m   o   o
>   Contact3xx d-   o   -   o   o   o
>   Contact485   -   o   -   o   o   o
> 
> For me this means that, in RFC 3261, Contact must be present in a 2xx
> to an INVITE.

Yes, but according to this table it's optional for 1xx. And 3262 does 
not update that, though with reliable 1xx the Contact is more likely to 
be needed to address the PRACK.

> So if we now look at Table 2 in RFC 3262 I see:
> 
>Header field  where   PRACK
>___
>Contact R   -
>Contact1xx  -
>Contact2xx  -
>Contact3xx  o
>Contact485  o
> 
> For me this means that a Contact header is "not applicable (-)" when
> replying to a PRACK, nothing about the 1xx for the INVITE in acse the
> 1xx requires "100rel".
> 

-- 
Best regards,
Dmitry Akindinov


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Re: [Sip-implementors] sending DTMF as Notify

2008-10-02 Thread Attila Sipos
>>INFO is more appropriate to send DTMF using "application/dtmf-relay"
>>content-type.
 
That is a matter of opinion - some would say that DTMF should be solicited 
before it is sent.
I guess though in this case, the NOTIFY is unsolicited anyway.
It is unusual for unsolicited NOTIFY to be used for DTMF (though I have seen 
unsolicited NOTIFY for call-waiting)
 
I do agree that INFO is more usual for unsolicited DTMF transport.
 
>> Please note that this is not IANA registered application mime type though.

True.  "application/dtmf-relay" is what Cisco have used, so many others have 
also adopted it.
If a big player uses something non-standard, it can end up becoming a kind of 
de-facto standard.
 
Regards,
Attila
 
 



From: [EMAIL PROTECTED] on behalf of Vikram Chhibber
Sent: Thu 02/10/2008 10:19
To: Vivek Gupta
Cc: sip-implementors@lists.cs.columbia.edu
Subject: Re: [Sip-implementors] sending DTMF as Notify



INFO is more appropriate to send DTMF using "application/dtmf-relay"
content-type. Please note that this is not IANA registered application mime
type though.
For example:

INFO sip:[EMAIL PROTECTED] <[EMAIL PROTECTED]> SIP/2.0
Via: SIP/2.0/UDP 172.80.2.100:5060
From:  >;tag=43
To:  
>;tag=9753.0207
Call-ID: [EMAIL PROTECTED]
CSeq: 25634 INFO
Content-Length: 26
Content-Type: application/dtmf-relay

Signal= 1
Duration= 160


On Thu, Oct 2, 2008 at 1:44 PM, Vivek Gupta <[EMAIL PROTECTED]>wrote:

> Hi,
>
> I need information on how to send DTMF tones as unsolicited Notify method
> within an established dialogue. Can anyone explain the
> steps to implement the same?
>
> Information on any SIP soft-phone that supports DTMF as Notify would be of
> great of help?
>
> With regards,
> Vivek GUpta
> ___
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> Sip-implementors@lists.cs.columbia.edu
> https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
>
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Re: [Sip-implementors] SIP Proxy inserting Option Tags

2008-10-02 Thread Attila Sipos
>>Is a SIP proxy allowed to insert Option tags when forwarding a
>>request?
 Not usually but this RFC allows it.  I guess the reason is that protecting 
against a poxy's resource leakage is sometimes considered more important than 
allowing a call to proceed without the requirement.
 
 
>> In that case, why "Require" is preferred than "Supported" in RFC4028?

The require is used because the proxy absolutely requires it.
 
Regards,
Attila
 



From: [EMAIL PROTECTED] on behalf of Victor Pascual Ávila
Sent: Wed 01/10/2008 18:43
To: sip-implementors@lists.cs.columbia.edu
Subject: [Sip-implementors] SIP Proxy inserting Option Tags



RFC3261
20.32 Require
The Require header field is used by UACs to tell UASs about options
that the UAC expects the UAS to support in order to process the
request.

RFC4028
8.1.  Processing of Requests
the proxy MAY insert a Require header field with the value 'timer'
into the request.

Is a SIP proxy allowed to insert Option tags when forwarding a
request? In that case, why "Require" is preferred than "Supported" in
RFC4028?

Cheers,
--
Victor Pascual Ávila

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Re: [Sip-implementors] SIP Proxy inserting Option Tags

2008-10-02 Thread Attila Sipos
>>IMHO a proxy CANNOT add a Require option tag, can it?

it can but it is bit of a hack.  RFC4028 itself does not recommend it.  However 
it allows it to try to force a session timer even if the request originator 
does not support it.
 
  with the value 'timer', the proxy MAY insert a Require header field
   with the value 'timer' into the request.  However, this is NOT
   RECOMMENDED.  This allows the proxy to insist on a session timer for
   the session.  This header field is not needed if a Supported header
   field was in the request; in this case, the proxy would already be
   sure the session timer can be used for the session.
 
If "unsupported: timer" is returned, the UA, as you say, won't understand it.  
But it's of no consequence, the UA can't do anything anyway.  The Unsupported 
response is for a user to try to understand why the request failed - if it 
failed due to "unsupported: timer", then the user can conclude that an upstream 
proxy inserted the "timer" requirement (but RFC4028 knowledge is required - not 
ideal I suppose).
 
 
Regards,
Attila
 



From: [EMAIL PROTECTED] on behalf of Iñaki Baz Castillo
Sent: Wed 01/10/2008 19:30
To: sip-implementors@lists.cs.columbia.edu
Subject: Re: [Sip-implementors] SIP Proxy inserting Option Tags



El Miércoles, 1 de Octubre de 2008, Victor Pascual Ávila escribió:
> RFC3261
> 20.32 Require
> The Require header field is used by UACs to tell UASs about options
> that the UAC expects the UAS to support in order to process the
> request.
>
> RFC4028
> 8.1.  Processing of Requests
> the proxy MAY insert a Require header field with the value 'timer'
> into the request.
>
> Is a SIP proxy allowed to insert Option tags when forwarding a
> request? In that case, why "Require" is preferred than "Supported" in
> RFC4028?

I don't understand how a proxy can add a "Require" option tag. Let me explain
the issue with an example:

- A sends INVITE to B through proxy P.
- P adds "Require: ".
- B replies "420 Bad Extension".
- "420" arrives to P who forwards it to A.
- So A receives the "420" with a header "Unsupported: ".
- A didn't add that option tag so it doesn't understand what happened.

IMHO a proxy CANNOT add a Require option tag, can it?


--
Iñaki Baz Castillo

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[Sip-implementors] XML inside SIP

2008-10-02 Thread Manoj Priyankara (NOD)


Hi All,

Does anyone know the usage of XML inside SIP messages (like NOTITY) ? 

Thanks
BR,
Manoj

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Re: [Sip-implementors] sending DTMF as Notify

2008-10-02 Thread Vikram Chhibber
INFO is more appropriate to send DTMF using "application/dtmf-relay"
content-type. Please note that this is not IANA registered application mime
type though.
For example:

INFO sip:[EMAIL PROTECTED] <[EMAIL PROTECTED]> SIP/2.0
Via: SIP/2.0/UDP 172.80.2.100:5060
From:  >;tag=43
To:  
>;tag=9753.0207
Call-ID: [EMAIL PROTECTED]
CSeq: 25634 INFO
Content-Length: 26
Content-Type: application/dtmf-relay

Signal= 1
Duration= 160


On Thu, Oct 2, 2008 at 1:44 PM, Vivek Gupta <[EMAIL PROTECTED]>wrote:

> Hi,
>
> I need information on how to send DTMF tones as unsolicited Notify method
> within an established dialogue. Can anyone explain the
> steps to implement the same?
>
> Information on any SIP soft-phone that supports DTMF as Notify would be of
> great of help?
>
> With regards,
> Vivek GUpta
> ___
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> Sip-implementors@lists.cs.columbia.edu
> https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
>
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[Sip-implementors] sending DTMF as Notify

2008-10-02 Thread Vivek Gupta
Hi,

I need information on how to send DTMF tones as unsolicited Notify method 
within an established dialogue. Can anyone explain the 
steps to implement the same?

Information on any SIP soft-phone that supports DTMF as Notify would be of 
great of help?

With regards,
Vivek GUpta
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Re: [Sip-implementors] Early dialogs, reliable responses and PRACK addressing

2008-10-02 Thread Iñaki Baz Castillo
2008/10/2, Dmitry Akindinov <[EMAIL PROTECTED]>:

> > RFC 3262 says clearly that "The provisional response ***MUST establish a
> dialog*** if one is not yet created".
> >
>
>  ... they just refer to the fact that Tables 1 and 2 in rfc3262 extend
> tables 2 and 3 in rfc3261 and the Contact is marked as optional in 1xx
> responses. If 3262 clearly stated that reliable provisional responses MUST
> have Contact - we would not have this issue.
>  Yet, how simpler the life would be if rfc3262 (at least) stated clearly
> that with reliable provisional responses the Contact header is required :-)

Are you sure of the meaning of that Table 1 in RFC 3262?

Note that RFC 3261 in table 2 says:

  Header field  where   proxy ACK BYE CAN INV OPT REG
  ___
  Contact Ro   -   -   m   o   o
  Contact1xx   -   -   -   o   -   -
  Contact2xx   -   -   -   m   o   o
  Contact3xx d-   o   -   o   o   o
  Contact485   -   o   -   o   o   o

For me this means that, in RFC 3261, Contact must be present in a 2xx
to an INVITE.


So if we now look at Table 2 in RFC 3262 I see:

   Header field  where   PRACK
   ___
   Contact R   -
   Contact1xx  -
   Contact2xx  -
   Contact3xx  o
   Contact485  o

For me this means that a Contact header is "not applicable (-)" when
replying to a PRACK, nothing about the 1xx for the INVITE in acse the
1xx requires "100rel".

-- 
Iñaki Baz Castillo
<[EMAIL PROTECTED]>

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Re: [Sip-implementors] Early dialogs, reliable responses and PRACK addressing

2008-10-02 Thread Iñaki Baz Castillo
2008/10/2, Harsha. R <[EMAIL PROTECTED]>:

> Its not clear to me as to why the 18X is expecting a Contact. The purpose of
>  Contact is to do a target refresh.
>  18X missing a Contact header means a target refresh has not happened. In
>  this case, address the PRACK to
>  the original remote target( mostly the one used for  INVITE).
>
>  If all goes well, PRACK reaches the intended UAS and  call goes through;

I don't agree here. The purpose of an-indialog request is to arrive
just to the UAS in that dialog, not to others UAS with same AoR.

If you send a PRACK (in-dialog request) with the same RURI as the
initial INVITE then the proxy between UAC and UAS must do again a
lookup to change the RURI and possibly do parallel forking. This will
cause an in-dialog request arriving to other UAS registered with same
AoR, each of them will reply "482 Call/Leg doesn't exist".

IMHO that is not the purpose SIP was designed, maybe it's just a black
hole, "legal", but incorrect. If we keep as "valid" any exotic
possibility not strictly defined in the RFC's then SIP would become a
pain.


-- 
Iñaki Baz Castillo
<[EMAIL PROTECTED]>

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