Part 4
How SIP Transforms
Enterprise Communications
In This Part
ᮣ Understanding how SIP and the PSTN work together
ᮣ Getting familiar with SIP trunks
ᮣ Federating SIP “islands”
ᮣ Matching up phone numbers to URIs
S
IP will fundamentally improve the efficiency of communi-
cations between enterprises and their partners, suppli-
ers, and customers. The initial wave of VoIP benefits has
been primarily limited to intra-enterprise communications.
Communications between enterprises, even those that are
VoIP-enabled, still require a circuit-switched handoff that
impacts voice quality, adds complexity, and introduces
unnecessary expense through intermediate carriers. But
SIP promises to change all of that.
This chapter discusses how the worlds of SIP and the
PSTN (public switched telephone network) will be intercon-
nected and how enterprise communications will change
through the introduction of SIP trunk services and federation
services.
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