Configuring Sip Trunk - HP FlexNetwork MSR Series Configuration Manual

Configuring SIP trunk

This chapter describes how to configure SIP trunk.
Background
As shown in
through the internal PBX, and external calls are placed over a PSTN trunk.
Figure 58 Typical telephone network
With the development of IP technology, many enterprises deploy SIP-based IP-PBX networks as
Figure
shown in
calls are still placed over a PSTN trunk. The problem is that the enterprises have to maintain both the
SIP network and PSTN trunk, which increases the difficulty of network management.
Figure 59 SIP+PSTN network
As more enterprise IP-PBX networks run SIP and more ITSPs use SIP to provide basic voice
communication structures, enterprises urgently need a technology that can connect the enterprise
IP-PBX network to the ITSP over SIP. This technology is called SIP trunk. A typical network diagram
of SIP trunk is shown in
The SIP trunk function can be embedded into the voice gateway or the firewall deployed at the edge
of an enterprise private network. The device providing the SIP trunk function is called the SIP trunk
device, or the SIP trunk gateway.
Figure 58, on a typical telephone network, internal calls of the enterprise are made
59. Internal calls of the enterprise are made by using the SIP protocol, and external
Figure 60.
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