Telephony Devices
Any IP end device that can be entered into a route group can be considered
a telephony device. For example, a device that is configured to use H.323
gateways, such as an IP SoftPhones or Microsoft NetMeeting can be considered
a telephony device.
The route pattern dialing structures are usually used to connect IP phone
calls destined for external gateways or external Cisco CallManagers using H.323.
What this allows for is the ability to use alternate paths if the primary is unable
to accept or admit calls. For example, intraoffice calls that use WAN connections
as the primary path and the PSTN as the secondary path can choose the secondary
path to complete the call if the WAN is saturated. On the other hand,
devices that reside on the same Cisco CallManager are unable to use alternate
routes, so if there is a problem within the LAN, the phones are unable to reroute
to the PSTN to complete the call.