Information Technology Reference
In-Depth Information
If a user dials the number 5551234, both dial peers match, but the router chooses to use
dial peer 2 because it is a more specific match (5551... matches 1000 numbers while 555[1-
3]... matches 3000 numbers). Now, Example 6-16 shows what happens if you add a third
dial peer to this configuration.
Example 6-16
Sample Dial Peer Configuration 2
dial-peer voice 1 voip
destination-pattern 555[1-3]...
session target ipv4:10.1.1.1
dial-peer voice 2 voip
destination-pattern 5551...
session target ipv4:10.1.1.2
dial-peer voice 3 voip
destination-pattern 5551
session target ipv4:10.1.1.3
If the user again dials 5551234, the router uses dial peer 3 to route the call. Likewise, the
router processes only the 5551 digits and drops the 234 digits. This can be useful for
emergency patterns such as 911 or 9911 (in North America) because the call is immedi-
ately routed when a user dials this specific pattern.
Tip:
If you ever have a question of which dial peer will match a specific string, Cisco
routers include a handy testing feature. From privileged mode, enter the command
show
dialplan number
<
number>
, where
number
is the number you want to test. The router dis-
plays all the matching dial peers in the order in which the router will use them. The router
lists more specific matches first.
Tip:
Because the router immediately routes the call after it makes a specific match, it is
best to avoid overlapping dial-plans if possible.
Avoiding overlapping dial-plans may be impossible at times. In these cases, you need to
get creative with your dial peers to accomplish your objectives. For example, if you are re-
quired to have a dial peer matching the destination pattern 5551 while a second dial peer
has the destination pattern 5551..., you could use a configuration like this as a solution:
dial-peer voice 2 voip
destination-pattern 5551...
session target ipv4:10.1.1.2
dial-peer voice 3 voip
destination-pattern 5551T
session target ipv4:10.1.1.3
Notice the T wildcard after 5551, which matches 0-32 digits. Users dialing extension
5551 now have to press the pound key (#) after they finish dialing or wait the 10-second
