Subject: [Sipping] Comments on draft--calhoun-sip-aaa-reqs-03.txt

From: "Harri Hakala (LMF)" <[email-masked]>
Date: Tue, 29 Jan 2002 09:59:28 +0100

Hi,

I have a few comments on the draft-calhoun-sip-aaa-reqs-03.
http://search.ietf.org/internet-drafts/draft-calhoun-sip-aaa-reqs-03.txt

Since this draft describes the AAA requirements for IP 
telephony/Multimedia, I would like to add a few accounting requirements
to the draft.
I think also that it would be good state what kind of events may
trigger generation of accounting records and what kind of information
needs to be reported.

I made a proposal for introductory text for body of the draft describing
the accounting mechanism and listed some accounting requirements
in the requirement section.

I have not been following the Sipping list discussions so far, so please
excuse me if some of my points have been discussed already or if
some of my points are out of scope of this list. 

Section 2.3 Invitation
----------------------
Sections 2.3.1 Invitation terminating in the mobile node and
         2.3.2 Invitation originating from the mobile node
------------------------------------------------------------
I would like to change the description of accounting in these
chapters in the following way:

During the SIP session establishment, the SIP serves MAY initiate
accounting session towards Accounting server in the home or visited
network. SIP servers MAY generate several accounting records during
the SIP session. At the end of the SIP session, a final accounting 
record should be issued that includes a summary of the SIP session. 

The accounting records should include accounting information that is
necessary for billing and inter-network settlement purpose. Accounting
information such as user identities (called and calling party Ids),
SIP call Id, used media types, request-URI, QoS parameters (requested/
negotiated quality of service), accounting correlation Id, SIP session
duration should be recorded.

Any change during the SIP session that MAY affect the charge of SIP 
session (e.g. change of media type, additional service requested,
call redirection) should be recorded as an accounting
record. For example during session forwarding, the initial calling party
(A) MAY incur the charges from A to B while the forwarding party MAY incur
charges due to the 'forwarded' session. Also, if the called party requests
additional media components with regard to the initial request from calling
party then called party MAY be charged for these additional components.

AAA server MAY also return at the SIP session establishment the 
accounting-interim-information to the SIP server, which advices the SIP 
server when to generate the interim accounting records and if cumulative or
non-cumulative accounting model MUST be used. The traditional telco world
currently makes use of, and prefers, non-cumulative accounting information,
therefore any interim accounting information MAY be non-cumulative. 

If the SIP extensions (for example Instant messaging, presence service) are
used some of the request or response messages in these extension MAY trigger 
generation of accounting information. For example SUBSCRIBE MAY trigger 
generation of one time event accounting record, session based instant messaging
MAY trigger generation of accounting session and INFO message MAY trigger 
generation of interim message. It MUST be configurable in the SIP servers or 
AAA server MAY inform the SIP servers when to generate accounting records or
which SIP messages triggers generation of accounting information.

Accounting data related to bearer payload (e.g. number of transmitted
packets, used bandwidth) is assumed to be handled by other mechanisms
than SIP and is not included in these requirements. However a unique 
accounting correlation Id MAY exist, which correlates the SIP session with 
specific bearer(s)in the access network. If the unique correlation Id exist,
it MUST be included in all accounting records to be able to correlate the
accounting information from SIP session to used bearer in the access network.

3.0 Requirements
----------------
Here is my proposal for requirements. 

XX. SIP servers MUST be able to provide relevant accounting information
    for billing and inter-network settlement purpose to home and visited
    AAA servers. Both one time event accounting records and session base
    (START, INTERIM, STOP records) accounting MUST be supported.  

XX. Any change during the SIP session that affects the charge of SIP session
    MUST be recorded over AAA accounting protocol. 

XX. It MUST be possible to divide the accounting of the SIP session into 
    different parts, so that different parties can incur charges for different
    parts of the SIP session. 

XX. The AAA accounting protocol MUST support accounting per media component 
    (e.g. voice, video). AAA accounting Protocol MUST enable different parties
    to be charged per media component. 

XX. Both cumulative and non-cumulative accounting model MUST be supported.

XX. It MUST be option to configure the SIP servers when to generate accounting
    records. Alternatively the AAA server MAY inform SIP servers when to 
    generate accounting records.

XX. If possible the accounting for SIP session MUST be correlated to the 
    bearer in the access network.
 
XX. There MUST be support for real-time and non-real time accounting. 

Regards............Harri

_______________________________________________
Sipping mailing list  https://www1.ietf.org/mailman/listinfo/sipping
This list is for NEW development of the application of SIP
Use [email-masked] for questions on current sip
Use [email-masked] for new developments of core SIP