The Assignment of Partitions
Partition Name Devices Designated to Partition
SE-Users All office telephony devices
SE-PSTN All devices with routes destined for the PSTN
Table 9.7 The Assignment of Calling Search Space
Calling Search Space Partitions Devices Assigned
Unrestricted SE-Users All telephony devices
SE-PSTN that can make calls
SE-Internal SE-Users Telephony devices that cannot
call outside the local office
One of these calling search spaces would be labeled Unrestricted (to denote
the lack of restrictions on the calling device).This calling search space would
then have SE-Users and SE-PSTN associated with it.The second calling search
space (called SE-Internal) would then have only SE-Users associated with it.
Office users in the Unrestricted calling search space will be allowed to dial
anywhere, while telephony devices associated with the SE-Internal calling search
space will only be allowed to call internally.
From this basic configuration, you could add all sorts of calling features,
depending on the needs of your office.These include:
Limiting telephony devices to intrasite (local office) calling
Limiting telephony devices to intrasite calling, with emergency
calling ability (emergency calling is required for most, if not all, office
configurations)
Intrasite and intersite (external offices) calling
Intrasite and intersite calling, with emergency calling capability
Intrasite, intersite, emergency, and local PSTN calling
Intrasite, intersite, emergency, and national PSTN calling
Unrestricted calling (includes all the preceding, plus international calling)
These partitions and calling search spaces can allow autonomous dial ranges
on a partition basis. Extension and access codes located within different partitions
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AVVID Dial Plans • Chapter 9 309
can have overlapping number schemes, and still work independently of each
other.This is usually seen in the implementation of a centralized call processing
system. In this example, all sites that use the same Cisco CallManager can dial the
number 9 to access the PSTN, even if they are located on different WAN segments.
When using a centralized Cisco CallManager for call processing, certain conditions
apply to overlapping users and extensions located at other sites.These
include:
Overlapping internal dial plans are supported if there is an implementation
of, or need for, voice mail on those extensions.This prevents issues
with the Cisco CallManager sending calls to voice mail and having to
decide which partition the call is destined for.The Cisco CallManager is
not designed to be intuitive, so a call directed to ext. 3637 in Seattle
cannot be distinguished from a call directed to ext. 3637 in San
Francisco.Voice mail requires unique extensions for identification.
If you do not require voice mail, you can have multiple sites with the
same extension.These extensions can be reached via:
The PSTN, dial the area code (if necessary), local access (exchange)
code (747), followed by the full directory number (3637).
The WAN, through the implementation of translation tables.The
tables can allow prepending of a unique code (sometimes referred to
as a steering code) to occur on extensions that overlap.This steering
code is then removed from the call when the destination is reached.