automatically rerouted over the service provider SIP
network to another enterprise location. For enterprises,
this system offers great flexibility in providing a local
presence in all their markets while routing calls to a
centralized call center for more efficient service.
ߜ Cost savings: For enterprises, SIP networking means
reducing the monthly recurring cost of separate PSTN
and data circuits to the premises. When you remove
voice circuits, you reduce the number of TDM T1 inter-
faces on the IP PBX, because hundreds of VoIP calls can
come from the same hardware footprint as a single T1
interface. Service providers may also offer reduced toll
charges to customers when SIP is used as the interface
to the PSTN.
Session Border Controllers (SBCs for short) are devices
that sit at the edge of a SIP enterprise network and a carrier
or ISP network cloud. Among the multiple functions these
devices can provide, some SBCs have been designed to sup-
port both inward and outward translation of URIs to E.164
(phone number addressing).
A simplified communications
Architecture
Enterprises can benefit from the simplification of enterprise
networks through the standardization on SIP — this is true
for both internal and external communications. As SIP
becomes ubiquitous in both service provider and enterprise
networks, it introduces a single standard interface for all con-
nectivity, whether for adding endpoints, deploying contact
center adjunct services, or even connecting trunk services
for external communications. Proprietary signaling protocols
and hardware-intensive digital/analog interfaces give way to a
simple, logical SIP interface that connects application servers
residing on industry-standard platforms. With SIP as a unifying
protocol, you can dramatically reduce the need for dedicated
hardware gateways and devices. Variants of voice-centric T1
and E1 standards will begin to diminish, as SIP globally stan-
dardizes the interface.
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