■ A local call is handled entirely by the router and does not travel over an external network.
■ On-net calls can be routed through one or more voice-enabled routers, but the calls remain on the same network.
■ An off-net call occurs when a user dials an acces code from a telephone directly connected to a voice-enabled router or PBX to gain access to the PSTN.
■ Voice port call types include local, on-net, off-net, PLAR, PBX to PBX, intercluster trunk, and on-net to off-net calls.
■ Voice ports on routers and access servers emulate physical telephony switch connections.
■ Analog voice port interfaces connect routers in packet-based networks to analog tow-wire or four-wire analog circuits in telephony networks.
■ FXS, FXO, and E&M ports have several configuration parameters.
■ CAMA is used for 911 and E911 services.
■ DID service enalbes callers to dial an extension directly on a PBX or packet voice system.
■ You can set a number of timers and timing parameters for fine-tuning a voice port.
■ The show, debug, and test commands are used for monitoring and troubleshooting voice functions in the networks.
■ Dial peers are used to identify call source and destination endpoints and to define the characteristics applied to each call leg in the call connection.
■ An end-to-end voice call consists of four call legs.
■ A dial peer is an addressable call endpoint.
■ POTS dial peers retain the characteristics of a traditional telephony network connection.
■ When a matching inbound dial peer is not found, the router resorts to the default dial peer.
■ The destination pattern associates a telephone number with a given dial peer.
■ When determining how inbound dial peers are matched on a oruter, it is important to note whether the inbound call leg is matched to a POTS or VoIP dial peer.
■ Outbound dial-peer matching is completed on a digit-by-digit basis.