1. SESSION-ID Backward COMPATIBILITY
SESSION-ID Backward COMPATIBILITY
Christer Holmberg
INSIPID Interim, October 4th 2012
© Ericsson AB 2012

2. TERMINOLOGY KAPLAN ENTITY INSIPID ENTITY
Implementing draft-kaplan-dispatch-session-id
Draft-00 referenced by 3GPP
Transfer case not covered (introduced in -02)
Draft-03 latest
Must decide which version to use as base for backward compatibility
INSIPID ENTITY
Implementing the to-be-defined INSIPID mechanism
“2 part” session identifier value
Both endpoints contribute to the session identifier value

3. ABNF KAPLAN ENTITY INSIPID ENTITY
Session-ID = "Session-ID" HCOLON sess-id *( SEMI generic-param )
sess-id = 32(DIGIT / %x61-7A) ; 32 chars of [0-9a-z] draft-00
sess-id = 32(DIGIT / %x61-66) ; 32 chars of [0-9a-f] draft-03
INSIPID ENTITY
Re-usage of KAPLAN syntax:
Part 1: sess-id
Part 2: generic-param
Session-ID:f81d4fae7dec11d0a76500a0c91e6bf6;param=dd5tder11d0a76500a0c91e6bf6

4. ABNF: RETRIEVED REQUIREMENTS
REQ-SYN-1: The INSIPID session identifier syntax MUST be backward compatible with the syntax in draft-kaplan-session-id-XX.
Header field name and value
REQ-SYN-2: An INSIPID entity MUST be prepared to receive a session identifier generated by a KAPLAN entity.
No remote part added in the SIP response.

5. UA Behavior: KAPLAN UAC UAS
“The UAC MUST re-use the same Session-ID for in-dialog messages, and for any out-of- dialog request it retransmits or re-generates in response to a 3xx, or it re-formulates due to failure responses.”
Draft-03: same Session-ID value:
Out of dialog REFER
Refer-To header field must contain Session-ID value as embedded header field
Out of dialog INVITE with Replaces header field
Reason: retain value during transfer
Multiple SIP dialogs with same value
UAS
“A UAS compliant with this document MUST copy a received Session-ID value in a request, into responses and subsequent upstream requests sent within the dialog.”

6. UA: RETRIEVED REQUIREMENTS
REQ-UA-1: It MUST be possible for an INSIPID entity to detect that it is communicating with a KAPLAN entity.
The INSIPID entity does not add its own part to a received session identifier
REQ-UA-2: An INSIPID entity, when communicating with a KAPLAN entity, MUST NOT modify the Session-Id value within a dialog.
Not in a response, nor in a mid-dialog request

7. NEXT STEP
BASED ON OUTCOME OF DISCUSSIONS, SUBMIT NEW VERSION OF ”DRAFT-KAPLAN”.

8. THANK YOU!