Datasheet

Cisco Preferred Architecture for
Midmarket Collaboration PAGE 17
Call Control
For endpoints without assigned PSTN-based direct inward dial (DID) numbers (no E.164 number representation exists),
create enterprise-wide unique endpoint addresses outside of the default +E.164 domain. These endpoint addresses
should be in line with the internal dialing habit defined to reach these endpoints. If, for example, the abbreviated inter-site
dialing habit to reach a set of non-DID endpoints in a given site is 84915XXX, then these non-DID endpoints should use
this numbering scheme for their endpoint addresses.
In addition to the primary numeric endpoint addresses, administrators can provision alphanumeric URIs (for example,
[e-mail]) in Cisco Unified CM to serve as aliases for the primary addresses, and users can enter the URI as an
alternate way to dial the destination endpoint.
Routing
The routing portion of the dial plan enables users to reach the correct destinations when they use the defined dialing
habits.
The primary numeric routing is based on +E.164 numbers. External routes to other transport networks such as the PSTN
also use the +E.164 scheme. Endpoint addresses in +E.164 format provide +E.164 on-net dialing without any further
configuration. All other numeric dialing habits, such as abbreviated inter-site and intra-site dialing, are implemented as
overlays by adding the appropriate translation patterns to the dial plan to map from the implemented dialing habit to the
+E.164 global routing address format. This allows users to reach the same endpoint by means of different dialing habits,
depending on user preference.
Alpha-numeric URIs, as aliases for numeric addresses, provide an alternative means of reaching endpoints. The benefits
of URI dialing and routing include:
•
Conformity with the native dialing habit on most video systems
•
Easier business-to-business connectivity
•
Direct mapping from instant messaging identifiers to addresses (easier escalation of business-to-business IM
sessions to voice and/or video), although technically IM identifiers and SIP URIs are not necessarily identical
If an endpoint is enabled for business-to-business calls over the Internet, Cisco recommends associating a SIP URI to the
device so that the business-to-business routing logic can be based on SIP URIs.
As with numeric routing, if an alias or SIP URI is recognized as an internal destination and is associated with a specific
device, then Cisco Unified CM sends the call to that device. However, if the dialed SIP URI does not match any registered
endpoint alias, Cisco Unified CM uses SIP route patterns to determine where to send the call. For example, if the dialed
alias [e-mail] does not exist internally, Cisco Unified CM uses a SIP route pattern (such as *.com) to send
the call to Expressway-C as a business-to-business call.
Directory Integration
To enable users to search contacts and dial from the directory, integrate Cisco Unified CM with the organization’s LDAP
directory. Although Cisco Unified CM allows the creation of local user contacts, LDAP directory integration is required
when using Cisco Jabber because it provides a single location for directory management and enables users to
authenticate to Cisco Unified CM and Cisco Jabber by using their LDAP directory credentials.
Cisco Unified CM pulls user and contact information from LDAP directories and synchronizes user parameters — name,
surname, username, telephone number, and SIP URI — when changes occur. For example, use the telephoneNumber
attribute to populate the Telephone Number field in the Cisco Unified CM directory. The format of phone numbers in the
corporate directory must be globally significant and must match one of the defined dialing habits. Corporate directories
typically should have all phone numbers in +E.164 format (leading “+” followed by the fully qualified global number) as
long as a DID exists. Only this format allows the phone number in the corporate directory to be used universally inside
and outside the enterprise. Non-DID numbers that are not in +E.164 format could be used to dial uses internally from the
directory, but they would have no significance outside the enterprise. Use the mail attribute to populate the Directory URI
field in the Cisco Unified CM directory if URI dialing is used.
The IM and Presence Service pulls user and contact information from Cisco Unified CM.