SIP vs. API

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(No Transcript)
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SIP vs. API

• How Will You Be Developing Your Next
  Application?(SIP-01)

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Competing methods
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Development Building Blocks
Your Application
Compiled
XML
Graphical
C/C
Java
VoiceXML
NETANN
API
MSCML
MSML/MOML
Drivers
SIP
Hardware
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API What is it?

• If all else fails, refer to Wikipedia
• API
• An application programming interface (API) is a
  source code interface that a computer system or
  program library provides to support requests for
  services to be made of it by a computer program.

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Legacy API Architecture
Application
Proprietary
Proprietary
API
API
Proprietary
Proprietary
Device Driver
Device Driver
H.100
T1 Interface Hardware
Resource Hardware
PSTN
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API Development

• Key Attributes
• Powerful
• Feature Rich
• Highly Efficient
• Highly Complex
• Slow to Develop
• Hard to Debug
• Proprietary (mostly)

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Development Building Blocks
Your Application
Compiled
XML
Graphical
C/C
Java
VoiceXML
NETANN
API
MSCML
MSML/MOML
Drivers
SIP
Hardware
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SIP What is it?

• Wikipedia
• SIP
• The Session Initiation Protocol (SIP) is an
  application-layer control (signalling) protocol
  for creating, modifying, and terminating sessions
  with one or more participants. These sessions
  include Internet telephone calls, multimedia
  distribution, and multimedia conferences. (cit.
  RFC 3261).

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SIP Where does it fit?
RTP
SIP
HTTP
SMTP
L5
TCP
UDP
L4
IP
L3
L2
Ethernet
PPP
Copper
Fiber
Wireless
L1
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SIP Development

• Key Attributes
• Open
• Standard
• Interoperable
• Easy to Debug
• Inefficient
• Moving Target
• Slow to evolve

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SIP Architecture
Application
Service CreationEnvironment
SIP Protocol Stack
SIP
LAN
Media Gateway Resource
MediaResource
PSTN
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Two Classes of Resources

• Media Gateways
• Provide connectivity to existing TDM
  infrastructure
• 90 of installed base is still TDM
• Media Resources
• IVR Play / Record / DTMF
• Conferencing
• Fax
• Tone Detection/Generation
• Announcements
• Transcoding

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Speeds Development Time
Customer A Just over 3 Man-years to integrate
and test with a Legacy PCI Blade
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PCI
Same customer using SIP based hardware, 88 less
time to market!
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Integration Time in Man-Years
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SIP
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Development Building Blocks
Your Application
Compiled
XML
Graphical
C/C
Java
VoiceXML
NETANN
API
MSCML
MSML/MOML
Drivers
SIP
Hardware
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NetAnn What is it?

• NetAnn
• RFC 4240 as of December of 2005
• Predecessor to MSCML.
• Basic announcements
• Simpler conference model (no control dialog)
• Doesnt provide for mid-call requests and
  responses.

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MSCML What is it?

• MSCML Media Server Control Markup Language
• RFC 4722 in November 2006
• Provides services to users at an application
  level
• Services specified in user part of URI.
• For example Conf service implies a star
  connection topology with a mixer at the center,
  or PlayCollect connects a player and a
  dtmf-receiver to the call
• Conf, IVR (Play, PlayCollect, PlayRecord,
  FaxPlay, FaxRecord)
• Command oriented protocol (vs scripted)
• MSCML IVR syntax is modeled on the H.248 and MGCP
• Includes the composite PlayCollect and PlayRecord
  functions

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MSCML - Sample

• Example of a Play command
• lt?xml version"1.0" encoding"utf-8"?gt
• ltMediaServerControl version"1.0"gt
• ltrequestgt
• ltplay id"234"gt
• ltpromptgt
• ltaudio url"http//10.3.0.2/hello.wav"/gt
• ltvariable type"date" subtype"ymd"
  value"19760102"/gt
• ltvariable type"silence" value"5"/gt
• ltvariable type"duration" value"2"/gt
• lt/promptgt
• lt/playgt
• lt/requestgt
• lt/MediaServerControlgt

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MSCML Conferencing Create
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MSCML Conferencing Play
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MSML / MOML What is it?

• MSML Media Sessions Markup Language
• Device Control Protocol that focuses on internal
  media server resources
• SIP is normally concerned with the behavior
  external to the media server
• Provides a mechanism for invoking MOML or VXML
  scripts.
• Provides a mechanism for creating conferences and
  modifying their topologies.
• Does not provide for IVR control
• MOML Media Objects Markup Language
• MOML is a scripting languages that provides a
  defined set of useful IVR primitives play,
  generate dtmf, recognize dtmf, record, recognize
  speech, and others
• Primitives can be combined into groups, and
  multiple groups can be established concurrently.
  Lots of flexibility at the cost of complexity
• It is a scripting language with an internal state
  machine, but only 2 primitives have state, and
  they only have 2 states (stop/go).
• Absence of flow control limits scripts to
  functions rather than applications (eg VXML)
• IETF Draft (no RFC)

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MSCML vs MSML/MOML

• Application Level Services vs Device Control
• MSML provides explicit internal connection
  topology.
• MSCML provides predefined services with implicit
  internal connection topologies
• Provides a less complex interface for 99 of
  whats required.
• Scripting
• MOML provides a script execution capability to
  build composite functions.
• State Machines within primitives are so limited
  as to be of little general use.
• Requires a script execution framework.
• MSCML provides defined composite functions
• For example PlayCollect/Record provide
  integration between the Play and the
  Collect/Record functions. Much simpler for 99
  of use cases
• No script engine required provides performance
  advantages as well as simplicity

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Who supports what?
MSCML / NetAnn
MSML / MOML
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Media Control -Bottom Line

• Neither MSCML nor MSML/MOML are likely to be the
  Final Answer.
• Both rely on INFO messages which the IETF SIP
  arbiters do not like
• Both will allow you to do what you need to get
  done
• MSCML is our favorite
• Greater standards coverage (RFC vs not RFC)
• Easier to use (Operates at application level vs
  device control)
• More widely adopted
• Better adapted to 3GPP MRF (IVR mapping to H.248
  used in MRFC-to-MRFP)
• Discussion is carried out in the mediactrl -
  Media Control BOF Discussion List
• Final Answer likely 2 to 3 years out.

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Will we need APIs and SIP?
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How do they compare
Capability / Feature API SIPNetAnn SIPMSCML
TDM Bus Switching (H.100) Yes No No
Industry Standard (RFC?) No Yes Yes
Basic IVR Yes Yes Yes
Complex IVR Yes No Yes
Mixing/Recording Yes No No
Simple Conference Yes Yes Yes
Complex Conference Controls Yes No Yes
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The Future

• Expect many new applications to leverage SIP
• With one of the media server control protocols
• APIs will continue, but only for very complex
  apps.
• Secret our SIP and MSCML uses our API under the
  covers!
• Expect continued refinement
• of SIP and related media server protocols

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Questions?
?
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More information
Booth 115