Building a Foundation for
Standardized, Intelligent
Communications
SIP, defined in IETF standards, is a structured, text-based pro-
tocol that is modeled after HTTP, or HyperText Transport
Protocol, the language that powers the World Wide Web.
Because SIP is text-based and similar to HTTP, application
developers and system engineers will have an easier time
developing and integrating applications with communica-
tions systems.
SIP’s architecture consists primarily of SIP endpoints and
SIP servers. Endpoints are also called user agents — the pro-
grams and devices that actually perform the communications
between end-users. In small organizations, the user agents
can be smart enough to communicate to one another without
the need for servers. In large enterprises, centralized SIP
servers such as proxies, registrars, and presence servers,
facilitate user agent communications. SIP components, and
even an example call scenario, are found in Part 2.
SIMPLE (SIP for Instant Messaging and Presence Leveraging
Extensions) is an important standard that facilitates instant
messaging communication. SIMPLE is essentially a standardi-
zation of SIP’s presence features. We describe SIMPLE in more
detail in Part 2.
Where Will SIP Take
Communications
in the Future?
SIP, extensible and versatile as it is, continues to grow and
evolve. In the near future, you’ll likely see SIP become inte-
grated into business applications with several types of
functionality — far beyond simple click-to-call hyperlinks.
Applications will be able to make communications routing
and other decisions based upon interaction with users.
Part 1: The Case for SIP
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