Typical Applications - HP FlexNetwork MSR Series Configuration Manual

Figure 60 All IP-based network
Features
SIP trunk has the following features:
•
Only one secure and QoS guaranteed SIP trunk link is required between a SIP trunk device and
the ITSP. The SIP trunk link can carry multiple concurrent calls, and the carrier only
authenticates the link instead of each SIP call carried on this link.
•
The internal calls of the enterprise are placed by the enterprise IP-PBX. The outbound calls of
the enterprise are forwarded by the SIP trunk device to the ITSP, and are finally routed to the
PSTN by the device in the ITSP. Enterprises do not need to maintain the PSTN trunk, which
reduces the costs of hardware and maintenance.
•
By setting destination addresses, the enterprise can connect to multiple ITSPs, making full use
of ITSPs all over the world, and save on call costs.
•
With the SIP trunk device deployed, the entire network can use the SIP protocol to better
support IP communication services, such as voice, conference, and instant messaging.
•
A SIP trunk device differs from a SIP proxy server. The SIP trunk device initiates a new call
request to the ITSP on behalf of the user after receiving a call request from the user, and both
the user and the ITSP communicate only with the SIP trunk device. During the forwarding
process, the SIP trunk device forwards both signaling messages and RTP media messages.

Typical applications

The SIP trunk device is deployed between the enterprise IP-PBX and the ITSP. All internal calls are
placed by the enterprise IP-PBX. All outbound calls are forwarded by the SIP trunk device to the
ITSP through the SIP trunk link.
technology.
Figure 61
shows a typical network diagram for the SIP trunk
196