
a company can certainly gain cost savings and other effi-
ciencies, the real benefit is that these efforts also serve as a
steppingstone towards next-generation communications
applications powered by SIP.
Consider a business communications solution where SIP is
the common interface providing integration between enter-
prise networks and service provider networks. While roaming
in a service provider network, users can stay in touch with
their virtual enterprise anywhere, anytime, any place — as
though they had never left the premises.
⻬ Users in such an environment can instantly receive
enterprise voice message notifications while out of the
office.
⻬ Users, such as doctors, who work across multiple loca-
tions, don’t have to carry yet another phone, pager,
or PDA.
⻬ Services support improves because service manage-
ment can locate field technicians within a customer
location very quickly and provide better service to cus-
tomers.
⻬ Administrative assistants can use presence to quickly
locate their staff members to get attention to a matter
that requires immediate action.
⻬ SIP-enabled user devices can respond to a phone call by
responding with a short IM that lets the caller know
about the person’s availability.
SIP is well suited for mobile environments. SIP’s registration
function is similar to that in cell networks. When a user turns
on a SIP device, it registers the user and sends the device’s
URI to the registrar server, which routes calls to and from the
user. This system ties together multiple communication silos
(for example, e-mail, IM, desk phone, cell phone, and so on)
using a single address that can reach the user regardless of
location. Native mobility is one of the reasons that the Third-
Generation Partnership Project (3GPP), which is defining
specifications for third-generation (3G) mobile systems, has
adopted SIP as the primary signaling protocol.
Part 3: How SIP Transforms User Communications
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