Subject: [AAA-WG]: Accounting questions

From: "Guillermo Guardia-Lozano (ECE)" <[email-masked]>
Date: Fri, 6 Jul 2001 14:27:57 +0200

Hello,
 After reading the base draft  I have several question regarding "Accounting" and maybe 
somebody in the list can clarify them. First I have included the parts of the document that
all together lead me to confusion and, at the end, my questions.
Thanks in advance.

Chapter 10.0
When a service only makes use of the Accounting portion of the
Diameter protocol, even in combination with an application, the
Session-Id is still used to identify user sessions. However, the
session termination messages are not used, since a session is
signaled as being terminated by issuing an accounting stop message.

Chapter 11.5
A particular value of Accounting-Session-Id MUST appear only in one
sequence of accounting records from a DIAMETER client, except for the
purposes of retransmission. The one sequence that is sent MUST be 
either one record with Accounting-Record-Type AVP set to the value
EVENT_RECORD, or several records starting with one having the value
START_RECORD, followed by zero or more INTERIM_RECORD, and a single
STOP_RECORD. 

Chapter 11.6
However, there are certain applications that require multiple
accounting sub-sessions. Such applications would send messages with a
constant Session-Id AVP, but a different Accounting-Session-Id AVP.

Chapter 13.3
The Accounting-Record-Number AVP (AVP Code 485) is of type Unsigned32
and identifies this record within one session. As Session-Id AVPs are
globally unique, the combination of Session-Id and Accounting-
Record-Number AVPs is also globally unique, and can be used in
matching accounting records with confirmations.  An easy way to
produce unique numbers is to set the value to 0 for records of type
EVENT_RECORD and START_RECORD, and set the value to 1 for the first
INTERIM_RECORD, 2 for the second, and so on until the value for
STOP_RECORD is one more than for the last INTERIM_RECORD.

Chapter 13.4
The Accounting-Session-Id AVP (AVP Code 44) is of type UTF8String,
following the format specified in section 10.7. The Accounting-
Session-Id is not used by the Diameter protocol, since the Session-Id
defined in [1] is used for both authentication/authorization and
accounting purposes. 

Q1-
If the service only makes use of the Accounting portion, but besides,
it requires multiple accounting sub-sessions ( constant Session-Id but
a different Accounting-Session-Id ), how is this session signaled as 
being terminated ? 
Is still applicable the "Accounting Session State Machine" in chapter 10.2 ?

Q2-
Are Accounting-Record-Numbers unique within the session ( Session-Id )
or unique within the accounting sub-session (Accounting-Session-Id ) ? 

Q3-
In the message format of <Accounting-Request> and <Accounting-Answer> 
the Accounting-Session-Id AVP appears as mandatory, but the AVP description
(chapter 13.4 ) says : "The Accounting-Session-Id is not used by the Diameter
 protocol, since ...." 
Is it coherent ?