User to user key signaling protocols
Download
1 / 22

User to User Key Signaling Protocols - PowerPoint PPT Presentation


  • 89 Views
  • Uploaded on

User to User Key Signaling Protocols. Ellis K Cave Sr. Principal Engineer InterVoice-Brite. DTMF - is it Signaling or Media?. DTMF was designed to provide address signaling at start of call network address signaling DTMF originally turned off during conversation part of call

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'User to User Key Signaling Protocols' - tallis


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
User to user key signaling protocols

User to User Key Signaling Protocols

Ellis K Cave

Sr. Principal Engineer

InterVoice-Brite


Dtmf is it signaling or media
DTMF - is it Signaling or Media?

  • DTMF was designed to provide address signaling at start of call

    • network address signaling

    • DTMF originally turned off during conversation part of call

    • Left on during call because of tip-ring polarity administration issues

SIP WG


Dtmf is it signaling or media1
DTMF - is it Signaling or Media?

  • PSTN service and application vendors discovered DTMF control in late 70s

  • Vendors standardized on the use DTMF for application control during call

    • simple user input mechanism

    • standard across all PSTN terminal device

  • Accidental provision of a standard user input model by the Telco made possible most of today’s complex telephony applications

SIP WG


The infamous octothorpe pound sign
The Infamous Octothorpe (pound sign)

  • Illustrates the confusion between network signaling and user signaling

  • VRU vendors use pound ‘#’ for application control

    • Input field termination

    • “Press pound when you complete your entry”

  • Network vendors use pound ‘#’ as call re-originate

    • “Press pound to disconnect the current LD call, and place another”

SIP WG


Network vs user signaling confusion
Network vs User Signaling Confusion

  • To differentiate between network and application functions, network providers had to require that the pound be held for over 2 seconds for network alerts

  • VRU vendors may still interpret a 2-second pound as an application function

SIP WG


Address signaling in a packet network
Address Signaling in a Packet Network

  • Current packet session protocols thoroughly deal with address signaling

    • DTMF is not required for address signaling on packet terminals

  • Packet network address signaling standards

    • H.323 - Q.931, H225

    • SIP Invite

  • Smart terminal aggregates address data input from caller

    • Terminal transmits aggregated address data in the call setup signaling message when user presses terminate (OK) key.

SIP WG


Dtmf replacement in a packet network
DTMF replacement in a packet network

  • DTMF-type address signaling is not required in a packet network

  • However, some type of user input keystroke signaling IS a requirement in a packet network for interactions with applications and other users

  • What will replace DTMF as application control in a packet network?

SIP WG


Most services in the packet network will require standardized user input
Most services in the packet network will require standardized user input.

  • Examples

    • voicemail

    • meet-me conferencing

    • recording/logging services

    • language translation services

    • hearing impaired service

  • To keep these applications simple, user input should be standardized across all terminal types

SIP WG


Questions
Questions standardized user input.

  • What do you want to have happen when a user presses a button on the keypad of a SIP desk phone during a SIP call ?

  • A cell phone?

    Answer

  • The same thing that happens when you press a key on the keyboard of a computer during a SIP call.

SIP WG


User signaling in a packet network
User Signaling in a Packet Network standardized user input.

  • H.323 defines user input indication - H.245

    • Intended specifically for DTMF

    • Assumes 16-key device 0-9, *, #, and A-D

  • SIP doesn’t address user input issue

  • Schulzrinne made H.323 to SIP proposal

    • Left out user input indication translation

SIP WG


Current proposals for sip dtmf
Current Proposals for SIP DTMF standardized user input.

  • http://www.ietf.org/rfc/rfc2833.txt.

  • http://www.ietf.org/internet-drafts/draft-ietf-sip-info-method-05.txt.

  • draft-kuthan-sip-infopayload-00.txt (expired).

  • http://www.ietf.org/internet-drafts/draft-choudhuri-sip-info-digit-00.txt.

  • http://www.ietf.org/internet-drafts/draft-culpepper-sip-info-event-00.txt.

  • http://www.ietf.org/internet-drafts/draft-agrawal-sip-h323-interworking-reqs

SIP WG


Where should you put user input
Where should you put User Input? standardized user input.

  • Should it go in the signaling protocol (SIP)?

    • The current Info Method proposals propose this approach

    • Does an application protocol belong in the session set-up/teardown signaling?

    • SIP Info Method has the right transport characteristics

      • guaranteed delivery

      • single packet

  • Should it go in the session description protocol (SDP)?

    • SDP currently only sets up media sessions

SIP WG


Where should you put user input1
Where should you put User Input? standardized user input.

  • Perhaps User Input needs its own session specifically for user signaling.

  • If an application using SIP expects to need user input (and most will), the user agent should use SDP to set up a user input session

  • User input sessions will be as common as streaming media sessions

SIP WG


User key input transport protocol requirements
User Key Input Transport Protocol Requirements standardized user input.

  • Keystroke-based

  • Requires guaranteed delivery

    • no dropped packets

  • Requires guaranteed sequencing

    • receiver should be able to get transmitted input events in transmit order

  • Duration information should be an option

  • User input signaling protocol should be the same whether it is a SIP phone, a PC, or a cell phone!

SIP WG


What are the choices
What are the Choices? standardized user input.

  • RTP stream

  • Info Method

  • New SDP session protocol

SIP WG


Rtp streaming for user key input
RTP streaming for User Key Input standardized user input.

  • Pros

    • Existing protocol

    • Guaranteed Sequencing

  • Cons

    • User Input is not a streaming function

      • single keystroke events

    • RTP is not guaranteed delivery

    • Overly complex protocol for simple keystrokes

      • RTSP, stats, jitter buffers, etc

      • Simple text chat apps would require RTP stack

    • User Input needs to be a separate session from audio stream

SIP WG


Sip info method for user key input
SIP Info Method for User Key Input standardized user input.

  • Pros

    • Existing protocol

    • Guaranteed delivery

    • Simple mechanism (part of SIP)

  • Cons

    • Architecturally, application and user data should NOT be in the signaling channel

    • Future applications using redirection and replication of user input for multi-party conferencing would be prevented

      • How do you redirect or multicast the SIP session Info Messages?

SIP WG


New sdp session for user key input
New SDP Session for User Key Input standardized user input.

  • Pros

    • Allows selection of appropriate transport protocol for reliable keystroke delivery

    • Separate session for User Key Input

    • Allows redirect & multi-unicast, etc.

  • Cons

    • Need to define new SDP protocol for User Key Input

    • Must use SDP to set up User Key Input session

SIP WG


Sdp supports
SDP supports standardized user input.

  • Video

  • Audio

  • Application

  • Data

  • Control

  • Which type of session is most appropriate?

SIP WG


Gateway requirements
Gateway Requirements standardized user input.

  • Gateway is the intelligent proxy for the dumb black phone in a SIP call.

  • Gateway never sees PSTN address signaling from terminal, only user key input

  • Job of the gateway is to convert DTMF to the new SIP User Key Input protocol

  • Gateway sets up User Key Input SDP session

SIP WG


Avoid the wap wml hdml webclip debacle
Avoid the WAP/WML/HDML/WebClip Debacle standardized user input.

  • Different protocol for each type of device

  • To avoid chaos, the User Key Input protocol should be standardized for all packet terminal devices.

  • The “one” numeric key should produce the same message in the User Key Input session on all devices.

SIP WG


Conclusions
Conclusions standardized user input.

  • SIP architecture needs a User Key Input mechanism

  • Best choice is a separate SDP session

  • Could be “application’ or “control” session type

  • User Input should be standardized across all terminal devices

  • Keystroke/event message map defined in standard across all terminal device types

SIP WG


ad