SIPPING Work Items

1
SIPPING Work Items

• Jonathan Rosenberg
• dynamicsoft

2
Registration Event Package Changes

• Add shortened event
• Indicates a decrease in registration interval
• Client should re-register before new expiration
• Includes an expiration parameter

3
Open Issues

• Default expiration matching default registration
  expiration
• Change to 4200s
• XML vs. sipfrag
• Why convert reg message to XML?
• Answer separate data from protocol
• There is data in XML not in registration

• Registration data can change through non-SIP
  means (administratively)
• Example shortening of registration
• Counter-arguments
• Size overhead
• No need for XML abstraction for simple data

4
App Interaction

• Who are we?
• Cullen Jennings, Eric Burger, Robert
  Fairlie-Cuninghame, Jonathan Rosenberg
• What are we doing?
• Stimulation with SIP!
• The way in which users interact with applications
  using stimulus
• Media
• Markups
• DTMF

5
What have we produced?

• Draft-rosenberg-sipping-app-interaction-00
• Overall framework
• Draft-burger-sipping-kpml
• Keypad Markup Language
• Think HTML for black phones
• Draft-jennings-sipping-app-info
• SIP extensions for the framework
• Draft-culpepper-sipping-app-interact-reqs
• Top level requirements

6
Open Issues

• The infamous SIP v. HTTP Debate
• Sending the results of a user keypress between a
  user interface and the application
• Interface between apps and UI dont depend on the
  type of UI (HTML, VoiceXML) -gt HTTP
• Security problem -gt SIP
• Quarantine -gt SIP?
• Routing argument -gt SIP
• This is a synchronous operation -gt HTTP, but do
  we care?

7
Focus Determination for KPML

• When a user enters a digit, which KPML amongst
  the ones from the various apps does it apply to?
• No way to know for sure
• Current draft says send it everywhere same as
  the PSTN
• Provides a central controller model to deal with
  cases where a single provider knows the rules
• Is that adequate?

8
KPML Post data in HTTP URI or Body

• ltassuming HTTPgt
• HTTP allows both. Does it matter.

9
Error Reporting for App-Info

• What if the App-Info URI is invalid?
• If the header appears in a request, you can
  reject the request with some error code
• But we allow it in responses.
• Options
• No error reporting
• Only send App-Info in requests
• Error reporting URI (infinite recursion problem)

10
Indicating Script Termination

• If the user dismisses a UI component, there is no
  way for the application to find out
• Same is true in the web, but
• Is this limitation OK for us?
• If not, we need to wrap app interactions in
  dialogs

11
Barge

• Framework has a very cool feature that allows IVR
  barging to be pushed to the endpoint
• KPML includes a barge parameter that causes media
  to be dropped when a regular expression is
  matched
• Means zero-latency barges in IVR better than
  PSTN
• Problem how to detect when its OK to start
  playing media again?
• Need some kind of media stream synchronization
• Marker bits -gt dont work
• PT changes -gt might work
• Others?

12
Too many solutions?

• Framework provides multiple ways to do the same
  thing
• Main one Composition Model
• Model I Pipe-and-filter
• Model II Central Server
• Model III Endpoint Controlled
• The ones that can be used depend on endpoint
  capabilities, introducing capability
  determination requirements

13
Hookflash

• Should hookflash be added to KPML as an event?
• Its been made historical in ISDN and other
  places
• If it knows enough to distinguish clear from
  hookflash, its functional and can send the right
  functional message
• This is a fallacy I think
• Opinions?