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T1/E1 Digital Voice Port Adapter Installation and Configuration
OL-3592-02
Chapter 4 Configuring the PA-VXA, PA-VXB, and PA-VXC
Configuring Voice over IP
Figure 4-4
Dial Peer Call Legs from the Perspective of the Destination Router
Inbound Versus Outbound Dial Peers
Dial peers are used for both inbound and outbound call legs. It is important to remember that these terms
are defined from the router’s perspective. An inbound call leg originates outside the router. An outbound
call leg originates from the router.
For inbound call legs, a dial peer might be associated with the calling number or the port designation.
Outbound call legs always have a dial peer associated with them. The destination pattern is used to
identify the outbound dial peer. The call is associated with the outbound dial peer at setup time.
POTS peers associate a telephone number with a particular voice port so that incoming calls for that
telephone number can be received and outgoing calls can be placed. VoIP peers point to specific devices
(by associating destination telephone numbers with a specific IP address) so that incoming calls can be
received and outgoing calls can be placed. Both POTS and VoIP peers are needed to establish VoIP
connections.
Establishing communication using VoIP is similar to configuring an IP static route: you are establishing
a specific voice connection between two defined endpoints. As shown in
, for outgoing calls
(from the perspective of the POTS dial peer 1), the POTS dial peer establishes the source (through the
originating telephone number or voice port) of the call. The VoIP dial peer establishes the destination by
associating the destination telephone number with a specific IP address.
Figure 4-5
Outgoing Calls from the Perspective of POTS Dial Peer 1
10354
IP cloud
Destination router
Call leg for POTS
dial peer 4
Call leg for VoIP
dial peer 3
Destination
Source
10355
(408) 526....
(310) 520....
10.1.2.2
Source
Destination
10.1.1.2
Voice port
0:D
Voice port
0:D
IP cloud
Source router
VoIP call leg
POTS call leg