PacketCable Functional Components
Chapter 4 PacketCable Network Architecture
TA 102/202 Technical Support Guide
4-9
PSTN Gateway
A PacketCable Network must be able to send calls to, and receive calls from the Public
Switched Telephone Network (PSTN) — you know, the telephone company. But, because
the PSTN is so much different than a PacketCable Network (its based on circuit-
switched technology), the PacketCable Network must employ an interface device called
a PSTN Gateway.
A PSTN Gateway carries out all the necessary interface functions between the two net-
works for both call signaling and so-called bearer traffic (the actual contents of calls).
Figure 4-6
PSTN Gateway
To enable operators to minimize cost and optimize their PSTN interconnection arrange-
ments the PSTN Gateway is broken down into three functional components:
•
Media Gateway (MG): serves as the interface between the two networks for media.
•
Signaling Gateway (SG): serves as the interface between the two networks for signal-
ing.
•
Media Gateway Controller (MGC): controls the Media Gateway.
Figure 4-7
PacketCable/PSTN Interface Architecture
PSTN Gateway
Serves as an interface device between the PacketCable
Network and the Public Switched Telephone Network (PSTN).
Divided into 3 functional components:
Media Gateway Controller
Maintains call state and controlls overall behavior of the PSTN Gateway.
Signaling Gateway
Provides signaling interconnection functions between the PSTN SS7
signaling network and the IP network.
Media Gateway
Terminates bearer (telephone call) paths and transcodes media between
the PSTN and the IP network.
MEDIA GATEWAY
CONTROLLER
MEDIA
GATEWAY
SIGNALING
GATEWAY
CMTS
CMS
MTA
PSTN GATEWAY
PSTN
PSTN BEARER TRUNKS
PSTN SIGNALING TRUNKS
BEARER
