Information Technology Reference
In-Depth Information
Tip:
If you create multiple dial peers with exactly equal destination patterns and prefer-
ences, the router will randomly choose a dial peer to use.
Looking at the Arizona router in Example 6-17, you can see that dial peer 10 is the more
preferred path to the Texas router. Because the connection uses VoIP dial peers, no auto-
matic digit stripping occurs and no digit-manipulation commands are required. (Keep in
mind that the no digit-strip, forward-digits, and prefix commands are only valid under
POTS dial peers anyhow.)
If the IP connection between Arizona and Texas fails, the Arizona router begins using the
next most preferred dial peer, which is dial peer 11. To overcome the automatic digit-strip-
ping feature of POTS dial peers, the
no digit-strip
command is used. (Otherwise, the
router would strip the 6 digit from the dialed number.) Because a four-digit number is in-
valid on the PSTN, the prefix 1512555 command adds the necessary prefix information to
get the call across the PSTN.
Note:
If the IP WAN fails, all the active calls established during the WAN failure will dis-
connect and be required to redial. There is no “dynamic failover” mechanism for calls
already established.
Practical Scenario 2: Directing Operator Calls to the Receptionist
This practical scenario is fairly simple. The organization shown in Figure 6-13 wants to di-
rect all calls to the operator number 0 to the receptionist at extension 5000.
FXO 1/0/1
PSTN
Receptionist
5000
Figure 6-13
Redirecting Operator Calls
Because this is a “universal” transformation (you always want to change the dialed number
0 to 5000), you can accomplish this objective using the
num-exp
global configuration
command, which is shown in Example 6-18.
