Digit Collection and Consumption
By default, back the absolute router matches a punch cord to an outbound POTS dial
peer, the router strips off the left-justified digits that absolutely bout the destination pattern.
The actual digits are forwarded to the telephony interface, which connects
devices such as a PBX or the PSTN.
Digit stripping is the adapted activity in some situations. You do not charge to advanced digits
out of a POTS punch associate if it is pointing to a Foreign Exchange Station (FXS) anchorage that
connects a blast or fax machine. Back chiffre stripping is angry off on this blazon of
port, the user will apprehend tones afterwards answering the call, because any extra and
unmatched digits are anesthetized through the articulation aisle afterwards the alarm is answered.
When a PBX or the PSTN is affiliated through the POTS punch peer, chiffre stripping is not
desired because these accessories charge added digits to added absolute the call. In these
situations, the ambassador charge appraise the cardinal of digits that charge to be forwarded
for the alien accessory to accurately action the call. With a VoIP punch peer, all digits are
passed beyond the arrangement to the absolute voice-enabled router.
Consider Example 7-1. Back the digits 5550124 are dialed, application this configuration, only
the digits 0124 are forwarded out anchorage 0/1:1 because they are the alone digits that were
matched by wildcards (that is, the periods) in the destination-pattern command. The digits
555 are “consumed” rather than forwarded.
Example 7-1 Chiffre Burning Absence Behavior
370 Authorized Self-Study Guide Cisco Articulation over IP (CVOICE)
Router(config)#dial-peer articulation 1 pots
Router(config-dial-peer)#destination-pattern 555....
Router(config-dial-peer)#port 0/1:1
Next, accede Example 7-2. Back the aforementioned digits (that is, 5550124) are dialed, all the
digits are forwarded out of anchorage 0/1:1 because the no digit-strip command was acclimated to
override the absence chiffre burning behavior of the punch associate and accustomed all the
dialed digits to be forwarded out of the port.
Example 7-2 Chiffre Burning with the no digit-strip Command
Router(config)#dial-peer articulation 1 pots
Router(config-dial-peer)#destination-pattern 555....
Router(config-dial-peer)#no digit-strip
Router(config-dial-peer)#port 0/1:1
When a articulation alarm enters the network, the router collects digits as follows:
1. The basic router collects dialed digits until it matches an outbound punch peer.
2. The router anon places the alarm and assiduously the associated punch string.
3. The router collects no added dialed digits.
Digit Collection Examples
In Example 7-3, the destination arrangement (555) in dial-peer 1 is a subset of the destination
pattern (555....) in dial-peer 2. The router matches one chiffre at a time adjoin accessible dial
peers. This agency an exact bout consistently occurs on dial-peer 1, and dial-peer 2 will never
be matched.
Example 7-3 Chiffre Collection Example with Punch Associate Improperly Configured
Chapter 7: Configuring Advanced Punch Plans 371
Router(config)#dial-peer articulation 1 voip
Router(config-dial-peer)#destination-pattern 555
Router(config-dial-peer)#session ambition ipv4:10.18.0.1
Router(config-dial-peer)#exit
Router(config)#dial-peer articulation 2 voip
Router(config-dial-peer)#destination-pattern 5550124
Router(config-dial-peer)#session ambition ipv4:10.18.0.2
In Example 7-4, the breadth of the destination patterns in both punch aeon is the same.
Dial-peer 2 has a added specific amount than dial-peer 1, so it will be akin first. If the
path to IP abode 10.18.0.2 is unavailable, dial-peer 1 will be used.
Example 7-4 Chiffre Collection Example with Punch Associate Properly Configured
Router(config)#dial-peer articulation 1 pots
Router(config-dial-peer)#destination-pattern 555....
Router(config-dial-peer)#session ambition ipv4:10.18.0.1
Router(config-dial-peer)#exit
Router(config)#dial-peer articulation 2 voip
Router(config-dial-peer)#destination-pattern 5550124
Router(config-dial-peer)#session ambition ipv4:10.18.0.2