View the Exhibit.

You administer the VoIP network shown in the diagram above.
The IP phone user that has been assigned dn 5545 dials 6045 and receives a busy signal.
Which of the following is most likely the problem?

A.
The dn 6045 is listed in the <None> search space.

B.
The IP phone at 5545 is using a device search space.

C.
The IP phone at 5545 is using a line search space.

D.
The IP phone at 5545 is using a search space that does not include NY60xxPT.

E.
The IP phone at 5545 is using a search space that does not include NY50xxPT.

F.
The IP phone at 5545 is using a search space that does not include LA65xxPT.

G.
The IP phone at 5545 is using a search space that does not include LA55xxPT.

Explanation:
The problem is most likely that the IP phone at extension 5545 is using a search space that does not include
the NY60xxPT partition. A partition is a logical grouping of Voice over IP (VoIP) route patterns and directory
numbers (dns). A search space is an ordered list of partitions that a device is allowed to search for patterns thatmatch a dialed number. A device that is not able to match a dialed number in any of the search spaces that are
assigned to the device will generate a busy signal. For example, an administrator could segregate local and
long distance route patterns into two partitions named LocalPT and LongDistancePT, respectively. The
administrator could then assign devices that should not be able to make long distance calls to a search space
named Local that includes only the LocalPT partition. Thus devices that have been assigned to only the Local
search space could not make long distance calls.
In the network shown above, the NY60xxPT partition contains an IP phone that has been assigned the dn 6045.
When the user at the IP phone that has been assigned the extension 5545 attempts to dial 6045, the user
receives a busy signal. Therefore, it is most likely that the IP phone that has been assigned extension 5545 has
not been assigned a search space that includes the NY60xxPT partition.
It is not likely a problem that the IP phone at 5545 is using a device search space. It is also not likely a problem
that the IP phone at 5545 is using a line search space. A device search space is a search space that is
assigned to a device itself. The information in a device search space will be searched no matter which line on a
device is chosen for the outgoing call. A line search space, on the other hand, is a search space that is
assigned to a single line on a device, not to the device itself. The information in a line search space will be
searched when the user chooses the line to which the search space is assigned as the outgoing line for the
call.
If a device is configured with both a device search space and a line search space, the device will combine the
two search spaces and search the information that is contained in the line search space first. For example, if
you assign the Local search space to a device and the LongDistance search space to a line on the same
device, the LongDistance search space will be searched first, even if the user dials a local extension. If the
same route pattern or dn exists in both search spaces, the LongDistance search space will be used to break
the tie.
It is not likely that dn 6045 is listed in the <None> search space. Any VoIP endpoint can match the route pattern
or dn that is contained within the <None> search space because every VoIP endpoint is assigned the <None>
search space by default. The <None> search space contains the <None> partition. The <None> partition
initially contains all the dns that are configured in the VoIP network. Therefore, you should move dns from the
<None> partition to a custom partition to limit specific pattern matching to specific endpoints. The IP phone at
5545 would be able to call the IP phone at 6045 if 6045 were listed in the <None> search space.
It is not likely that the IP phone at 5545 is using a search space that does not include the NY50xxPT partition,
does not include the LA55xxPT partition, or does not include the LA65xxPT partition. Nothing in the scenario
indicates that the IP phone at 5545 is receiving a busy signal when the user attempts to dial extensions that are
included in those partitions.

Cisco: Partitions and Calling Search Spaces: Understanding Partitions and Calling Search Spaces