Call Flow - Cisco AS5350 - Universal Access Server Configuration Manual

Chapter 6 Configuring Voice over IP
Table 6-1
A call leg from...
Originating device
Originating gateway
IP network
Destination gateway
A gateway conferences two call legs—an inbound POTS with an outbound VoIP or an inbound VoIP with
an outbound POTS—to create an end-to-end call through the gateway. A call that passes through both
an originating gateway and a destination gateway has four call legs.

Call Flow

Table 6-2
gateway respectively.
Table 6-2
Event
User sends dialed digits via public switched telephone network to gateway.
Gateway does the following:
•
•
•
•
Table 6-3
Event
Gateway receives dialed digits.
Gateway does the following:
•
•
•
•
OL-3418-02 B0
Call Legs
and Table 6-3 detail the general call flow from the perspective of an originating and destination
VoIP Call Flow, Originating Gateway View
Processes information (maps dialed digits, per information stored in
dial-peer configuration tables, either to an IP host that connects directly to
the destination gateway or to a PBX at the destination that can complete the
call).
Initiates H.323 session across network.
Processes voice signals and sends packets over network. As appropriate,
sends call-progress and other in-band signals.
Ends session.
VoIP Call Flow, Destination Gateway View
Processes information (maps dialed digits, per information stored in
dial-peer configuration tables, to a destination device).
Gateway participates in H.323 session across network.
Processes voice signals and sends packets over network. As appropriate,
sends call-progress and other in-band signals.
Ends session.
Cisco AS5350 and Cisco AS5400 Universal Gateway Software Configuration Guide
To...
Originating gateway
IP network
Destination gateway
Destination device
VoIP Basics
Is of this type...
Inbound POTS
Outbound VoIP
Inbound VoIP
Outbound POTS
Leg Type
Inbound POTS
Outbound VoIP
Leg Type
Inbound VoIP
Outbound POTS
plus inbound VoIP
6-3