1. Ad-hoc Resource Lists using SUBSCRIBE
58th IETF Meeting SIMPLE WG
Ad-hoc Resource Lists using SUBSCRIBE
draft-levin-simple-adhoc-list-00.txt
by Orit Levin
IETF58 / SIMPLE WG

2. Motivation
The ietf-simple-event-list-04 solves an acute problem of BATCHED notifications by introducing the RLMI schema.
This mechanism cannot be deployed in an interoperable manner without standard creation of “soft” or “hard” lists.
“Soft” list is required by many Presence applications.
IETF58 / SIMPLE WG

3. Problem Definition
The ad-hoc list is dynamically created and modified by a Watcher
The list creates a “soft state” in the Server (RLS)
The list exists only for the life-time of a SUBSCRIBE dialog
Notifications are being sent in any dynamically agreed format (PIDF, RLMI, etc.)
IETF58 / SIMPLE WG

4. The Proposed Solution Option Tag Name: adhoclist
MIME Media Type Name: application
MIME subtype name: adrl+xml
IETF58 / SIMPLE WG

5. The Proposed Solution IETF58 / SIMPLE WG Watcher Server PUA
| F1 SUBSCRIBE [ADRL] | |
| >| |
| F2 200 OK | |
|< | |
| F3 NOTIFY [RLMI] | |
| F4 200 OK | |
| | F5 Update presence |
| |< |
| F6 NOTIFY [RLMI] | |
| F7 200 OK | |
| F8 SUBSCRIBE [ADRL] | |
| F9 200 OK | |
| F10 NOTIFY [PIDF] | |
| F OK | |
IETF58 / SIMPLE WG

6. Example Messages Flow IETF58 / SIMPLE WG F1
Watcher Server PUA
| F1 SUBSCRIBE | |
| >| |
| F2 200 OK | |
|< | |
| F3 NOTIFY | |
| F4 200 OK | |
| | F5 Update presence
| |< |
| F6 NOTIFY | |
| F7 200 OK | |
| F8 SUBSCRIBE | |
| F9 200 OK | |
| F10 NOTIFY | |
| F OK | | F1
SUBSCRIBE SIP/2.0
To:
From:
Call-ID:
Event: presence
Require: adhoclist
Accept: application/cpim-pidf+xml
Accept: application/rlmi+xml
Contact:
Content-Type: application/adrl+xml
Content-Length: ...
[ADRL Document] F2
SIP/ OK
Accept: application/adrl+xml
Contact: sip:pres.example.com
Content-Length: 0
IETF58 / SIMPLE WG

7. Detailed Example Messages Flow
Watcher Server PUA
| F1 SUBSCRIBE | |
| >| |
| F2 200 OK | |
|< | |
| F3 NOTIFY | |
| F4 200 OK | |
| | F5 Update presence
| |< |
| F6 NOTIFY | |
| F7 200 OK | |
| F8 SUBSCRIBE | |
| F9 200 OK | |
| F10 NOTIFY | |
| F OK | | F3
NOTIFY SIP/2.0
From:
To:
Call-ID:
Event: presence
Subscription-State: active;expires=750
Contact: sip:pres.example.com
Content-Type: application/rlmi+xml
Content-Length: ...
[RLMI Document] F4
SIP/ OK
From:
To:
Content-Length: 0
IETF58 / SIMPLE WG

8. Detailed Example Messages Flow (Cont.)
Resources’ information on the RLS is updated by SIP or non-SIP means. (Details are out of scope. ) F6
NOTIFY SIP/2.0
To:
Call-ID:
Event: presence
Subscription-State: active;expires=750
Contact: sip:pres.example.com
Content-Type: application/rlmi+xml
Content-Length: ...
[RLMI Document] F7
SIP/ OK
To:
From:
Require: eventlist
Content-Length: 0
Watcher Server PUA
| F1 SUBSCRIBE | |
| >| |
| F2 200 OK | |
|< | |
| F3 NOTIFY | |
| F4 200 OK | |
| | F5 Update presence
| |< |
| F6 NOTIFY | |
| F7 200 OK | |
| F8 SUBSCRIBE | |
| F9 200 OK | |
| F10 NOTIFY | |
| F OK | |
IETF58 / SIMPLE WG

9. Detailed Example Messages Flow (Cont.)
SUBSCRIBE SIP/2.0
To:
From:
Call-ID:
Event: presence
Require: adhoclist
Accept: application/cpim-pidf+xml
Accept: application/rlmi+xml
Contact:
Content-Type: application/adrl+xml
Content-Length: ...
[ADRL Document] F9
SIP/ OK
To:
Accept: application/adrl+xml
Contact: sip:pres.example.com
Content-Length: 0
Watcher Server PUA
| F1 SUBSCRIBE | |
| >| |
| F2 200 OK | |
|< | |
| F3 NOTIFY | |
| F4 200 OK | |
| | F5 Update presence
| |< |
| F6 NOTIFY | |
| F7 200 OK | |
| F8 SUBSCRIBE | |
| F9 200 OK | |
| F10 NOTIFY | |
| F OK | |
IETF58 / SIMPLE WG

10. Detailed Example Messages Flow (Cont.)
Watcher Server PUA
| F1 SUBSCRIBE | |
| >| |
| F2 200 OK | |
|< | |
| F3 NOTIFY | |
| F4 200 OK | |
| | F5 Update presence
| |< |
| F6 NOTIFY | |
| F7 200 OK | |
| F8 SUBSCRIBE | |
| F9 200 OK | |
| F10 NOTIFY | |
| F OK | |
F10
NOTIFY SIP/2.0
To:
Call-ID:
Event: presence
Subscription-State: active;expires=650
Contact: sip:pres.example.com
Content-Type: application/rlmi+xml
Content-Length: ...
[RLMI Document]
F11
SIP/ OK
From:
To:
Content-Length: 0
IETF58 / SIMPLE WG

11. Relation to draft-camarillo-sipping-exploders-solution-00.txt
The draft proposes the following:
Generalization of the requirements for any method
Inside a dialog / No dialog
Identifying the different possible Server modes
Involved / Uninvolved
IETF58 / SIMPLE WG

12. Our Case: Ad-hoc Resource Lists using SUBSCRIBE
Classification:
B2BUA
“Uninvolved exploders”
Inside a dialog
IETF58 / SIMPLE WG

13. Our Case: Ad-hoc Resource Lists using SUBSCRIBE
It is an Excellent Study Case
Longtime identified requirements
Technically straightforward
No new security risks
IETF58 / SIMPLE WG

14. Proposed Next Steps Define as a WG Working Item in SIMPLE
The first “exploder” application and study case
The mechanisms for AD-HOC LIST definition and maintenance MUST be general
Start polishing the specification details on the list
The standardization timing is crucial here!
IETF58 / SIMPLE WG

15. Points for Further Discussion on the List
List unique identification
Stand-alone identifier?
Bind to a dialog?
Version numbering
Required?
Reflects the notifications numbering
Full list always vs. deltas are allowed
Are refreshes of the list required?
IETF58 / SIMPLE WG

16. Thank you!
IETF58 / SIMPLE WG