TCP/IP Tutorial and Technical Overview - IBM Redbooks

► Communication context
This is similar to the presence service in VoIP convergence. The Internet TV
stream can be one element within a communication context. Consider two
teenagers watching the same movie (in their respective houses) and instant
messaging each other at significant moments during the show. An alternative
example is the TV stream as a picture-in-picture option within a multimedia
conferencing service.
► Nomadicity
For an Internet TV service, nomadicity normally is interpreted as the user
being able to access the same service profile from a different location.
Performance-to-cost ratio changes are likely to result in handheld devices or
portable terminals capable of participating in Internet TV sessions.
► Emergency services
IPTV needs to continue existing television services to provide content
overlays notifying of emergency conditions (for example, a thunderstorm
warning).
► Content and service discovery
Assisted by a centralized or distributed directory, the user is able to search
and locate the video content from the terminals. The search can be text-,
picture-, or video-based. The content and the service available based on the
content is reported back to the user as the result of search.
As the cable and phone service providers are moving into the content service,
they face integration of various content providers. For example, a new search
for a TV title results in multiple IP flows to various servers, some of which
might contain the same content with varying format, abbreviation, or
technology.
► Digital rights management
IP network security and application security support DRM technology that
allows certification of the legitimacy of the original source of the video content,
authentication and authorization of the user to view the content, and clear
accounting among content creators, producers, traders, and users.
► Session management
Standard session management control commands must be built on top of the
SIP or RTCP or other protocols in order for users to initiate and control a
content delivery. Examples include play, rewind, forward, pause, stop, fast
rewind, and fast forward.
To meet the IPTV service requirements, a set of enabling capabilities have to
provide middleware in the SP space. Those enabling technologies are directly
supported by a number of IETF protocols including Real-Time Protocol,
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