Site-Code Dialing and Toll-Bypass
When you use site-code dialing, each site is assigned with a unique site code. For example,
a network with three sites could have the site codes 801, 802, and 803. If a user
wants to place a call to a remote site user, the dialed number would be the site code followed
by the actual extension. This form of abbreviated dialing greatly improves the enduser
experience because of shorter dialable numbers.
The calling-party number, also referred to as ANI, needs to include the appropriate site
code. This allows called users to call back directly using their missed-calls and receivedcalls
directory. You can use digit manipulation to support this as well.
You might also use site-code dialing to solve issues with overlapping numbering plans.
Because all extensions of a site are prefixed with a unique site code, an overlapping numbering
plan (where extensions in multiple sites overlap) can be turned into a unique
numbering plan.
Toll-Bypass Example
The example illustrated in Figure 7-23 and Example 7-21 shows the concepts of call routing
and path selection in a toll-bypass scenario.
Chapter 7: Configuring Advanced Dial Plans 407
IP WAN
PSTN
R1
192.168.1.1
Phone1-1
2001
Phone1-2
2002
Phone2-1
3001
Phone2-2
3002
Austin
San Jose
R2
V
2
If the WAN path is
not available, the
PSTN path is used.
1
WAN is the
preferred path with
preference 1.
Figure 7-23 Toll-Bypass Topology Example
Example 7-21 Toll-Bypass Configuration Example
408 Authorized Self-Study Guide Cisco Voice over IP (CVOICE)
R2(config)#dial-peer voice 21 voip
R2(config-dial-peer)#destination-pattern 2...
R2(config-dial-peer)#preference 1
R2(config-dial-peer)#session-target ipv4:192.168.1.1
R2(config-dial-peer)#exit
R2(config)#dial-peer voice 22 pots
R2(config-dial-peer)#destination-pattern 2...
R2(config-dial-peer)#prefix 14085552
R2(config-dial-peer)#preference 2
R2(config-dial-peer)#port 0/0/0:23
Figure 7-23 shows a scenario with two sites, San Jose and Austin. The Austin Cisco
Unified CME gateway is configured to route calls to San Jose primarily over the WAN,
and if the WAN link fails, the PSTN link should be used.
The first dial-peer configuration is used to route calls that match destination-pattern 2...
command to San Jose using the IP WAN. Because the dial peer is configured with a preference
of 1, it is preferred over the PSTN dial peer with a preference of 2.
The second dial-peer configuration is used to route calls that match destination-pattern
2... command to San Jose using the PSTN. The preference of 2 makes this dial peer inferior
to dial-peer 21 with a preference of 1.
Site-Code Dialing and Toll-Bypass Example
The example illustrated in Figure 7-24 and Examples 7-22 and 7-23 shows a scenario for
site-code dialing and toll-bypass.
Example 7-22 Site-Code Dialing and Toll-Bypass Example—R1’s Configuration
R1(config)#dial-peer voice 802 voip
R1(config-dial-peer)#destination-pattern 802....
R1(config-dial-peer)#session target ipv4:10.10.0.1
Example 7-23 Site-Code Dialing and Toll-Bypass Example—R3’s Configuration
R3(config)#dial-peer voice 801 voip
R3(config-dial-peer)#destination-pattern 801....
R3(config-dial-peer)#session target ipv4:10.10.0.2
San Jose
Site Code: 801
R3
1
User dials 801-2001.
2
Phone1-1 rings.
Calling number:
802-2002
Phone2-1
2001
Phone2-2
2002
IP WAN
PSTN
R1
10.10.0.2 10.10.0.1
Phone1-1
2001
Phone1-2
2002
Phone2-1
2001
Phone2-2
2002
Austin
Site Code: 802
San Jose
Site Code: 801
R3
Figure 7-24 Site-Code Dialing and Toll-Bypass Topology Example
Figure 7-24 shows a sample scenario for site-code dialing combined with toll-bypass. San
Jose has the site code 801, and Austin uses the site code 802. Also note that both sites
use extensions in the range of 2XXX. This is a typical overlapping numbering plan.
Following is the process the call goes through in this example:
1. A user in Austin wants to place a call to Phone1-1. Because Phone1-1 resides in San
Jose and has the site code 801, the user dials 801-2001 (that is, the site code 801 followed
by the extension 2001).
2. The call is routed over the IP WAN link to San Jose. Phone1-1 rings and displays the
calling number 802-2002 (that is, the site code 802 of Austin followed by the extension
of Phone2-2, which is 2002).