[Serusers] more about record route

Maxim Sobolev sobomax at FreeBSD.org
Sat Jan 3 19:10:40 CET 2004


Juha Heinanen wrote:

> Maxim Sobolev writes:
>  > 
>  > Well, IMO absence or presence of tag in the To header field should be 
>  > the definite difference between the two. INVITE which creates a dialg 
>  > would be To-tag-less, while one that refreshes a dialog would usually 
>  > have one. And if my memory serves according to the RFC INVITE is the 
>  > only type of message which can create a dialog.
> 
> also subscribe and even notify can create a dialog.

I said "according to the standard". ;)

Nevertheless, absence/presence of To tag rule would likely apply to any 
other requests creating a dialog.

-Maxim

12.1 Creation of a Dialog

    Dialogs are created through the generation of non-failure responses
    to requests with specific methods.  Within this specification, only
                                        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    2xx and 101-199 responses with a To tag, where the request was
    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    INVITE, will establish a dialog.  A dialog established by a non-final
    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    response to a request is in the "early" state and it is called an
    early dialog.  Extensions MAY define other means for creating
    dialogs.  Section 13 gives more details that are specific to the
    INVITE method.  Here, we describe the process for creation of dialog
    state that is not dependent on the method.

    UAs MUST assign values to the dialog ID components as described
    below.





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