Inbound versus Outbound Dial Peers
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 Voice over IP connections.
Establishing communication using Voice over IP is similar to configuring an IP static route: you are establishing a specific voice connection between two defined endpoints. As shown in Figure 8, for outgoing calls (from the perspective of the POTS dial peer 1), the POTS dial peer establishes the source (via the originating telephone number or voice port) of the call. The VoIP dial peer establishes the destination by associating the destination phone number with a specific IP address.
Figure 8 | Outgoing Calls from the Perspective of POTS Dial Peer 1 |
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Dial peer 1 | Dial peer 2 |
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S6613
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POTS call leg
VoIP call leg
To configure call connectivity between the source and destination as illustrated in Figure 8, enter the following commands on router 10.1.2.2:
port 1/0/0
session target ipv4:10.1.1.2
In the previous configuration example, the last four digits in the VoIP dial peer’s destination pattern were replaced with wildcards. This means that from access server 10.1.2.2, calling any number string that begins with the digits “1310555” will result in a connection to access server 10.1.1.2. This implies that access server 10.1.1.2 services all numbers beginning with those digits. From access server 10.1.1.2, calling any number string that begins with the digits “1408555” will result in a connection to access server 10.1.2.2. This implies that access server 10.1.2.2 services all numbers beginning with those digits. For more information about stripping and adding digits, see the “Outbound Dialing on POTS Peers” section.
Figure 9 shows how to complete the end-to-end call between dial peer 1 and dial peer 4.
Configuring Voice over IP for the Cisco 3600 Series