Adhoc Resource Lists using SUBSCRIBE

1
Ad-hoc Resource Lists using SUBSCRIBE
58th IETF Meeting SIMPLE WG

• draft-levin-simple-adhoc-list-00.txt
• by Orit Levin
• oritl_at_microsoft.com

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.

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.)

4
The Proposed Solution

• Option Tag Name adhoclist
• MIME Media Type Name application
• MIME subtype name adrlxml

5
The Proposed Solution

• Watcher Server
  PUA
• F1 SUBSCRIBE ADRL
  
• -------------------------------------gt
  
• F2 200 OK
  
• lt-------------------------------------
  
• F3 NOTIFY RLMI
  
• lt-------------------------------------
  
• F4 200 OK
  
• -------------------------------------gt
  
• 
  F5 Update presence
• 
  lt----------------------------------
• F6 NOTIFY RLMI
  
• lt-------------------------------------
  
• F7 200 OK
  
• -------------------------------------gt
  
• F8 SUBSCRIBE ADRL
  
• -------------------------------------gt
  

6
Example Messages Flow

• Watcher Server
  PUA
• F1 SUBSCRIBE
• --------------------------gt
  
• F2 200 OK
  
• lt--------------------------
  
• F3 NOTIFY
  
• lt--------------------------
  
• F4 200 OK
  
• --------------------------gt
  
• F5
  Update presence
• 
  lt---------------
• F6 NOTIFY
  
• lt--------------------------
  
• F7 200 OK
  
• --------------------------gt
  
• F8 SUBSCRIBE
• --------------------------gt
  

F1 SUBSCRIBE sipuser_at_pres.example.com SIP/2.0
To ltsipuser_at_pres.example.comgt From
ltsipuser_at_example.comgttag22222 Call-ID
2345_at_terminal.example.com Event presence
Require adhoclist Accept application/cpim-pidf
xml Accept application/rlmixml Contact
ltsipuser_at_terminal.example.comgt Content-Type
application/adrlxml Content-Length ... ADRL
Document F2 SIP/2.0 200 OK Toltsipuser_at_pres.e
xample.comgttag33333 From ltsipuser_at_example.com
gttag22222 Call-ID 2345_at_terminal.example.com
Event presence Accept application/adrlxml
Contact sippres.example.com Content-Length 0
7
Detailed Example Messages Flow

• Watcher Server
  PUA
• F1 SUBSCRIBE
• --------------------------gt
  
• F2 200 OK
  
• lt--------------------------
  
• F3 NOTIFY
  
• lt--------------------------
  
• F4 200 OK
  
• --------------------------gt
  
• F5
  Update presence
• 
  lt---------------
• F6 NOTIFY
  
• lt--------------------------
  
• F7 200 OK
  
• --------------------------gt
  
• F8 SUBSCRIBE
• --------------------------gt
  

F3 NOTIFY sipuser_at_terminal.example.com SIP/2.0
From ltsipuser_at_pres.example.comgttag33333 To
ltsipuser_at_example.comgttag22222 Call-ID
2345_at_terminal.example.com Event presence
Subscription-State activeexpires750 Contact
sippres.example.com Content-Type
application/rlmixml Content-Length ... RLMI
Document F4 SIP/2.0 200 OK From
ltsipuser_at_example.comgttag33333 To
ltsipuser_at_pres.example.comgttag22222 Call-ID
2345_at_terminal.example.com Content-Length 0
8
Detailed Example Messages Flow
(Cont.)
F5 Resources information on the RLS is updated
by SIP or non-SIP means. (Details are out of
scope. ) F6 NOTIFY sipuser_at_terminal.example.com
SIP/2.0 Fromltsipuser_at_pres.example.comgttag33333
To ltsipuser_at_example.comgttag22222 Call-ID
2345_at_terminal.example.com Event presence
Subscription-State activeexpires750 Contact
sippres.example.com Content-Type
application/rlmixml Content-Length ... RLMI
Document F7 SIP/2.0 200 OK To
ltsipuser_at_pres.example.comgttag33333 From
ltsipuser_at_example.comgttag22222 Call-ID
2345_at_terminal.example.com Event presence
Require eventlist Contact sippres.example.com
Content-Length 0

• Watcher Server
  PUA
• F1 SUBSCRIBE
• --------------------------gt
  
• F2 200 OK
  
• lt--------------------------
  
• F3 NOTIFY
  
• lt--------------------------
  
• F4 200 OK
  
• --------------------------gt
  
• F5
  Update presence
• 
  lt---------------
• F6 NOTIFY
  
• lt--------------------------
  
• F7 200 OK
  
• --------------------------gt
  
• F8 SUBSCRIBE
• --------------------------gt
  

9
Detailed Example Messages Flow
(Cont.)
F8 SUBSCRIBE sipuser_at_pres.example.com SIP/2.0
To ltsipuser_at_pres.example.comgt From
ltsipuser_at_example.comgttag22222 Call-ID
2345_at_terminal.example.com Event presence
Require adhoclist Accept application/cpim-pidf
xml Accept application/rlmixml Contact
ltsipuser_at_terminal.example.comgt Content-Type
application/adrlxml Content-Length ... ADRL
Document F9 SIP/2.0 200 OK To
ltsipuser_at_pres.example.comgttag33333 From
ltsipuser_at_example.comgttag22222 Call-ID
2345_at_terminal.example.com Event presence
Accept application/adrlxml Contact
sippres.example.com Content-Length 0

• Watcher Server
  PUA
• F1 SUBSCRIBE
• --------------------------gt
  
• F2 200 OK
  
• lt--------------------------
  
• F3 NOTIFY
  
• lt--------------------------
  
• F4 200 OK
  
• --------------------------gt
  
• F5
  Update presence
• 
  lt---------------
• F6 NOTIFY
  
• lt--------------------------
  
• F7 200 OK
  
• --------------------------gt
  
• F8 SUBSCRIBE
• --------------------------gt
  

10
Detailed Example Messages Flow
(Cont.)

• Watcher Server
  PUA
• F1 SUBSCRIBE
• --------------------------gt
  
• F2 200 OK
  
• lt--------------------------
  
• F3 NOTIFY
  
• lt--------------------------
  
• F4 200 OK
  
• --------------------------gt
  
• F5
  Update presence
• 
  lt---------------
• F6 NOTIFY
  
• lt--------------------------
  
• F7 200 OK
  
• --------------------------gt
  
• F8 SUBSCRIBE
• --------------------------gt
  

F10 NOTIFY sipuser_at_terminal.example.com SIP/2.0
Fromltsipuser_at_pres.example.comgttag33333 To
ltsipuser_at_example.comgttag22222 Call-ID
2345_at_terminal.example.com Event presence
Subscription-State activeexpires650 Contact
sippres.example.com Content-Type
application/rlmixml Content-Length ... RLMI
Document F11 SIP/2.0 200 OK From
ltsipuser_at_example.comgttag33333 To
ltsipuser_at_pres.example.comgttag22222 Call-ID
2345_at_terminal.example.com Content-Length 0
11
Relation todraft-camarillo-sipping-exploders-solu
tion-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

12
Our Case Ad-hoc Resource Lists using SUBSCRIBE

• Classification
• B2BUA
• Uninvolved exploders
• Inside a dialog

13
Our Case Ad-hoc Resource Lists using SUBSCRIBE

• It is an Excellent Study Case
• Longtime identified requirements
• Technically straightforward
• No new security risks

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!

15
Points for Further Discussionon 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?

16
Thank you!