Because SIP can determine through the Session Description
Protocol (SDP) what type of media stream the answering UA
can support, SIP can make intelligent choices on what type of
modality to use. (Part 2 explains more about SIP and SDP.)
However, IM is just the beginning. SIP has the unique and nat-
ural ability to support multiple media types within a single
communication session. This broad support creates a natural
solution for providing communications that adapt to the
user based on his or her situation and communication device
being used.
The term multimodality refers to the ability for a user (or
device or application) to communicate through more than
one mechanism. For example, a user may be able to input
text via voice or typing on a keyboard. An application such as
the Avaya SIP Softphone may be able to deliver either a text
or a voice message.
New SIP-enabled converged communications solutions will
enable users to interact with each other or with an appli-
cation in a variety of ways: input with speech, keyboard,
telephone keypad, mouse, and/or stylus, and output such as
synthesized speech, audio, plain text, motion video, and/or
graphics. Here are some examples that SIP-enabled solutions
can facilitate:
ߜ Voice/IM/video: A common interface provides access
to instant messaging, voice, and video services, tied
together with presence. Initiating communications is the
same for all modalities, and users can switch from one
communication method to another on the fly to best
meet their needs, perhaps within the context of a single
communication session!
ߜ Inline translation services: A SIP request, originating
with an English-speaking user, might contain a Web
Services request to translate a message into another
language for a non-English-speaking recipient.
ߜ Multimodal messaging: A SIP-enabled voice messaging
system could provide additional features such as:
• Voice-mail headers to the end-user via text.
• Display-enhanced voice-mail by delivering text or
graphics menus instead of voice-based menus.
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