Cisco Unified CallManager Express Dial Plan
This chapter describes the key elements of your Cisco Unified CallManager Express (Cisco Unified CME) dial plan:
•POTS Dial Peers
•VoIP Dial Peers
•Digit Manipulation Features
•Other Cisco Unified CME Dial Plan Features
Note For additional information, see the "Related Documents and References" section.
POTS Dial Peers
POTS dial peers are router configuration structures that point calls to a particular voice interface based on whether the dialed number matches certain criteria (as specified in the dial peer's destination-pattern). The voice interface can be a PSTN trunk, an analog phone, a fax machine, or an IP phone. The following example shows several sample POTS dial peers, including some for PSTN trunks and one for an analog phone or fax machine.
!11-digit long-distance PSTN dialing with an access code of 9
!7-digit local PSTN dialing with an access code of 9
!Analog phone or fax machine
dial-peer voice 2701 pots
VoIP Dial Peers
VoIP dial peers are router configuration structures that point calls to a particular IP interface based on the same criteria that are used for POTS dial peers (that is, matching the dialed number to the dial peer's destination-pattern). IP interfaces can be H.323 or Session Initiation Protocol (SIP). The following example shows an H.323 dial peer that directs calls to another site where all the extensions start with three.
dial-peer voice 3000 voip
session target ipv4:172.19.153.41
You can configure the extensions defined for your IP phones either by using the GUI or directly on the router using the ephone-dn command. As covered in "Cisco Unified CallManager Express Call Transfer and Forward,"an ephone-dn has two components:
•A virtual POTS dial peer for directing calls to the phone
•A virtual voice port
Note The voice ports and dial peers automatically generated by ephone-dns do not appear on the Cisco Unified CME running configuration. They can be seen only using more specific show commands.
The following example shows the definition on an ephone-dn and its associated POTS dial peer and
router# show running-config
call-forward noan 3105 timeout 10
router# show telephony-service dial-peer
dial-peer voice 20001 pots
router# show telephony-service voice-port
progress_ind setup enable 3
Digit Manipulation Features
Having an internal dial plan such as calling from one IP phone to another using a short extension of three or four digits, while also calling the outside world through the PSTN using fully qualified E.164 numbers, requires a certain amount of digit manipulation to add or subtract leading digits to or from an extension.
Typically, you have a trunk access code for an IP phone user to specify that a call should be routed to the PSTN as opposed to another extension. This access code must be translated to a PSTN-recognizable number before delivering the call to the PSTN. In a previous example you saw 9 used as the PSTN access code. Because this number matches the dial peer destination-pattern explicitly, it is deleted from the digit string forwarded to the PSTN. You can also see forward-digits commands in those POTS dial peers. These control how many of the numbers dialed by the IP phone user are forwarded to the PSTN, thereby offering simple digit manipulation within the dial peer statement itself.
"Voice Gateways,"covered more sophisticated digit manipulation features available in Cisco Unified CME, such as Cisco IOS translation rules.
Other Cisco Unified CME Dial Plan Features
Various other types of DNs or extensions also make up part of your dial plan in the sense that defining these features requires the definition of digits to dial to activate the feature. These features include speed dial, intercom, call park, and paging.
There are also other special types of numbers, such as the AA and voice mail pilot numbers, as well as MWI DNs. The transfer-pattern feature also plays a role in your dialing plan, because this definition determines what numbers your IP phone users can transfer calls to.
Class of Restriction (COR) and call blocking are features that determine which numbers might not be dialed on the system.
Note Dial plans are a wide topic that extends well beyond the scope of Cisco Unified CME. Visit the Cisco.com website and search for "Cisco Unified CME dial plans" for more information.