Trunk Types; Sip Registrations - Snom ONE IP Technical Manual

Deploying the snom ONE IP Telephone System
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Trunks can be dedicated to incoming, outgoing, or two-way traffic. Incoming trunks
carry calls into the system from an external network (i.e., PSTN, cellular, ITSP). Out-
going trunks carry calls away from the system to external networks. Two-way trunks
can be used for both sending and receiving calls. Figure 4-2 shows a SIP gateway trunk
connecting to the PSTN and a SIP registrations trunk connecting to the ITSP.
Cell Phone
Access
Figure 4-2. Using SIP Trunks for Communicating with External Networks
The snom ONE telephone system has three types of trunks: SIP registrations, SIP gate-
way, and SIP proxy. All act as an entry and exit point to an external network. The type
of network you are connecting to will determine which type of trunk you will need.

Trunk Types

SIP Registrations

When connecting to an ITSP (Internet telephone service provider), you may be re-
quired to use a SIP registration trunk due to the fact that the ITSP does not need to
PSTN
SIP
Gateway Registration
Trunk
LAN
SIP Phones
ITSP
(data router)
External
SIP
Trunk
Internal