sip and instant messaging. sip summit 2001 5.01.01 sip and instant messaging what does presence...
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SIP and Instant Messaging
www.dynamicsoft.comSIP Summit 2001 5.01.01SIP and Instant Messaging
What Does Presence Have to Do With SIP? How to Deliver Presence
Need a network that can identify users independent of location
Need a way to forward subscription requests to server handling that user
Need a way for user to tell server its location and other presence data
Need a network which can forward notifications to subscribers
Needs to scale Needs to deliver messages in
real time
What Does a SIP Network Do? Identifies users independent of
location Forwards requests (INVITE or
otherwise) to server handling user REGISTER allows network to tell
server its location and other information
Can forward messages back to originators in reverse direction
Scales Delivers messages in real time
(call setup delays)
www.dynamicsoft.comSIP Summit 2001 5.01.01SIP and Instant Messaging
Session Initiation and Presence/IM Share Other Requirements
Security Privacy Access controls Authentication
Carriage of MIME Data
Extensibility
www.dynamicsoft.comSIP Summit 2001 5.01.01SIP and Instant Messaging
SIP Already Provides Publication Capability REGISTER is a Publication Message
for Locations
Allows for SIP and Other URL Types
Multiple Entities Can Publish for the Same Address
SIP Caller Preferences Extension Allows for Attributes for Locations Mobile, landline Home, business Preferences Audio,video - MIME capability
Registrar
Registrar
www.dynamicsoft.comSIP Summit 2001 5.01.01SIP and Instant Messaging
Advantages of Using SIP for Presence and IM
Unifies Major Communications Services Voice/video IM Presence
Shared Databases
Shared Proxies
Shared Servers
www.dynamicsoft.comSIP Summit 2001 5.01.01SIP and Instant Messaging
Advantages of Using SIP For Presence and IM
Reduces Management Costs One infrastructure instead of two One NOC instead of two One set of managers instead of two
Enables New Combined Services Combined services integrate voice, video, IM, presence, web and email These new services will be a “killer app” for communications on
the Internet Delivery of combined services is greatly facilitated by alignment of
presence and communication signaling protocols Applications will be the clients of presence, not people
www.dynamicsoft.comSIP Summit 2001 5.01.01SIP and Instant Messaging
SIP Extension for Presence
New Entity: Presence Agent Purely logical entity Knows presence state of user Receives SUBSCRIBE requests Generates NOTIFY requests Co-located with proxy/registrar or User
Agent
Basic Operation Subscriber send SUBSCRIBE Routed to PA using normal SIP PA authorizes subscriber Acceptance contains presence state NOTIFY sent when state changes
Routed using SIP Record-Route
REGISTER
SUBSCRIBE
NOTIFY
Presence Agent +Proxy/Registrar = Presence Server
Proxy
Subscriber
Presentity
www.dynamicsoft.comSIP Summit 2001 5.01.01SIP and Instant Messaging
Important Details
Subscriptions Refreshed Expires mechanism, same as
with REGISTER, determines lifetime
Subscription Has “INVITE” Semantics for Record-route/ Contact Processing SUBSCRIBE creates a
“session” Refreshes have same Call-ID,
as do Notifications Intermediate entities can
record-route
Body of NOTIFY Contains Presence Data
Authorization and Access Controls Are Orthogonal Presence agent sends 200 OK
if subscription is accepted How it determines whether to
accept? DIAMETER Local policy database
configured via web CPL
www.dynamicsoft.comSIP Summit 2001 5.01.01SIP and Instant Messaging
Features of SIP For Presence Extension
End Users Can Perform Notifications Scalability
Presence Agent Function Can Migrate Network provides service when user is offline When user is online, subscriptions migrate to user
Offline Subscriptions Handled
Authorization from User Can Be Obtained by Presence Server
www.dynamicsoft.comSIP Summit 2001 5.01.01SIP and Instant Messaging
Features of SIP For Presence Extension continued
Multiple Entities Can Generate Presence Information for One Presentity Mobile phone, PDA, laptop and desktop PC
Multiple Presence Clients Can Be Online at Once
Traditional SIP Proxies Route SUBSCRIBE and NOTIFY
Presence Data is Orthogonal
www.dynamicsoft.comSIP Summit 2001 5.01.01SIP and Instant Messaging
SIP Extension for Instant Messaging
Operation of Extension Messages carried in SIP messages New method - MESSAGE Routed to recipient using normal SIP techniques Simple extension
Can also use SIP to establish “messaging” session On same level as RTP Can apply SIP tools – multiparty, transfers, etc.
Features Associates an IM with an existing call Any MIME data can be sent Routed by existing proxies and registrars Possible to have a different client for IM and communications
www.dynamicsoft.comSIP Summit 2001 5.01.01SIP and Instant Messaging
What Is Happening in the IETF? Instant Messaging and Presence Working Group (IMPP)
Could not come to consensus on a single proposal Chartered to develop CPIM – Common Presence and Instant Messaging –
common pieces across all protocols Presence data format Other groups will be chartered to do protocols
Application Exchange (APEX) Formerly IMXP Does IM and presence on top of a BEEP Mesh BEEP = Blocks Extensible Exchange Protocol
XML protocol for application frameworks
Presence and IM (PRIM) Not clear it will be chartered From scratch “TCP” protocol, much like SIP
SIMPLE
www.dynamicsoft.comSIP Summit 2001 5.01.01SIP and Instant Messaging
SIMPLE Group SIMPLE = SIP for Instant Messaging Leveraging Extensions
Working group approved February 2001 Co-chaired by Jon Peterson, Level(3) Co-chaired by Robert Sparks, dynamicsoft
Charter Encompasses SIP for presence specification
Built off of CPIM and SIP event framework May 01
SIP for IM specification May 01
www.dynamicsoft.comSIP Summit 2001 5.01.01SIP and Instant Messaging
Auto-Conference Web form with users POSTED
to controller
PresenceHTTPIMSIP Call
Application Server
Conference Server
Presence Server
Media Server
Controller initiates SUBSCRIBE session with presence server
On NOTIFYs update presence
When all online
Send IM to some with HTTP URL for accept
Use 3pcc to connect others to MS
HTTP POST of each accept/reject
Use 3pcc to connect each to same conference URL
MS fetches VoiceXML from AS
Information Resource Jonathan [email protected]