Figure 20 Linking PBXs over the IP Network (Remote Dial Peers)

Configuring Voice-over-IP

Both PBXs in this example use E&M interface Type 2, with four-wire operation and immediate-start signaling. The values for your configuration depend on your PBX and are available from your telecommunications department or the PBX manufacturer. For more information about E&M interface configuration commands, refer to the “VoIP Commands” chapter of the Cisco 1751 Router Software Configuration Guide.

In this example, West users can dial 5 and a four-digit extension to reach telephones in the East Office. East users can dial 5 and a four-digit extension to reach telephones in the West office.

The West router connects to the PBX through an E&M VIC port 0/0. This port is associated with a POTS dial peer for incoming calls. But you no longer need to associate every telephone number with its own port. Instead, you can configure a local dial peer as if all the West telephones (represented by a wildcard destination pattern) are connected directly to this port, as shown in the following commands:

West> enable

Password:

West# configure terminal

West(config)# dial-peer voice 111 pots

West(config-dial-peer)#destination-pattern 1408555....

West(config-dial-peer)# port 0/0

Configure VoIP dial peers for outgoing calls and associate destination phone numbers on the East router with that router IP address, as shown in Figure 20, and in the following commands:

West(config)# dial-peer

voice 121 voip

West(config-dial-peer)#

destination-pattern 1919555....

West(config-dial-peer)#

session target ipv4:192.168.11.3

West(config-dial-peer)#

exit

West(config)#

 

Figure 20 Linking PBXs over the IP Network (Remote Dial Peers)

408 555-xxxx

PBX

E&M VIC

0/0192.168.11.3

West

IP cloud

East

 

919 555-xxxx

PBX

 

dial-peer voice 121 voip

 

destination-pattern 1919555….

 

session target ipv4:192.168.11.3

 

num-exp 5…. 1919555….

Source

Destination

22343

Now configure number expansion so that numbers beginning with 5 (belonging to the East office) and sent by the West PBX to the West router are expanded into the full destination pattern:

West(config)# num-exp 5....

1919555....

Note You do not need to configure number expansion for calls from one West telephone to another West telephone because the PBX switches those calls.

Finally, enter the following global configuration voice-portcommand to configure the E&M port:

West(config)# voice-port 0/0

West(config-voice-port)# signal immediate

West(config-voice-port)# operation 4-wire

West(config-voice-port)# type 2

Cisco 1751 Voice-over-IP Quick Start Guide

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78-11259-05

 

 

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Cisco Systems CISCO1751 quick start Linking PBXs over the IP Network Remote Dial Peers