Matching Variable-Length Dial Peers
Routers are configured by default to match variable-length dial peers. As long as
the digits dialed match the pattern on the dial peer, it will continue to filter.
Once you are processing digits beyond the matching point, however, the router
will ignore them during the filtering process. For example, the dial string for
information, 5551212, would be properly matched with the following dial peers:
dial-peer voice 1 voip
destination-pattern 555
session target ipv4:10.1.100.1
dial-peer voice 2 voip
destination-pattern 5551212
session target ipv4:10.1.100.2
In order to disable the matching of variable-length dial peers, you would add
the $ character at the end of the destination-pattern.The $ character will stop the
dial peer from matching the digits that would come after it, even if they were
able to be processed by another destination-pattern, as in the following example:
dial-peer voice 1 voip
destination-pattern 555$
session target ipv4:10.1.100.1
dial-peer voice 2 voip
destination-pattern 5551212
session target ipv4:10.1.100.2
With the $ at the end of the destination pattern, the dial peer for 5551212
would not be matched.The pattern would only match up to the 555 configured
for dial peer 1.
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306 Chapter 9 • AVVID Dial Plans
As noted earlier, two-stage dialing collects digits that are dialed. It actually
collects them one by one and will attempt to match a dial peer after each digit is
dialed and processed. Once a match is found, the call will be routed. So, dialing
5551212 and using the following configuration:
dial-peer voice 1 voip
destination-pattern 555
session target ipv4:10.1.100.1
dial-peer voice 2 voip
destination-pattern 5551212
session target ipv4:10.1.100.2
you would see that the router would match the digits immediately to dial peer 1
and route the call.
In order for the digits to match the second dial peer, you would need to use
the timeout character (T) at the end of the destination pattern, in this case 555.
This would allow the digits a time limit with which to dial all numbers, and that
would allow the pattern to be matched to the best fit.This configuration would
look something like this:
dial-peer voice 1 voip
destination-pattern 555T
session target ipv4:10.1.100.1
dial-peer voice 2 voip
destination-pattern 5551212T
session target ipv4:10.1.100.2
Be aware that the router will also select dial peers based on whether the call
is inbound or outbound.