In a QSIG network, after a call is transferred or forwarded
to a phone in a third PINX, multiple connections through several PINX(s) can
exist for the call. After the call connects, the path replacement feature drops
the connection to the transit PINX(s) and creates a new call connection to the
Cisco Unified Communications Manager provides
"cooperating" PINX messages only. If configured for QSIG,
Cisco Unified Communications Manager responds to third-party vendor PINX
"inviting" messages, although
Cisco Unified Communications Manager will not originate
Cisco Unified Communications Manager does not support path retention.
Cisco Unified Communications Manager initiates path replacement for calls
that are transferred by joining and for calls that are diverted by forward
switching only. Calls that involve multiple trunks, for example, conference
calls, do not use path replacement; however, if you choose the QSIG option for
the Tunneled Protocol drop-down list box and check the Path Replacement Support
check box for gatekeeper-controlled or non-gatekeeper-controlled intercluster
trunks, path replacement occurs over the intercluster trunk and the other QSIG
intercluster or PRI trunk that is used to transfer or divert the call.
When you use CTI applications with path replacement, the leg
of the call that uses path replacement has a different Global Caller ID than
the originating leg of the call. After a call is forwarded or transferred, if
the remaining parties use the same
Cisco Unified Communications Manager, two Global Caller IDs exist, one for each
party. The system deletes one of the Global Caller IDs, both parties in the
call have the same Global Caller ID.
This section provides information on a few path replacement service
parameters. For a complete list of service parameters and for detailed
information on the parameters, click the ? that displays in the upper corner of
the Service Parameter Configuration window.
Because the QSIG protocol passes the extension number or
directory number but does not pass translated or inserted numbers, use QSIG
features, such as path replacement, in a network with a uniform dial plan. When
a private network uses nonunique directory numbers in the dial plan, you must
reroute calls through a PINX ID, which is a unique directory number for every
PINX in the network. The path replacement feature uses the PINX ID, if
configured, instead of the called or calling party number that the
describes. To configure the PINX ID, perform the following tasks in
Cisco Unified Communications Manager Administration:
Configure the PINX ID service parameter(s) for the Path
Replacement feature. (The Path Replacement feature uses the Cisco CallManager
Create a call pickup group that includes only the PINX ID.
Reserve the PINX ID call pickup group for PINX ID usage. Do not add
other directory numbers to this call pickup group.
Cisco Unified Communications Manager provides the Path Replacement Calling
Search Space service parameter, so you can configure the calling search space
that the cooperating PINX uses to send the outbound SETUP message to the
requesting PINX. If you do not specify a value for the Path Replacement Calling
Search Space service parameter, the requesting PINX uses the calling search
space of the end user that is involved in the call.
You configure Path Replacement settings in the Service
Parameter window for the Cisco CallManager service. Path Replacement service
parameters include Path Replacement Enabled, Path Replacement on Tromboned
Trunks, Start Path Replacement Minimum Delay Time, Start Path Replacement
Maximum Delay Time, Path Replacement PINX ID, Path Replacement Timers, Path
Replacement Calling Search Space, and so on. To obtain information about these
parameters, click the ? that displays in the Service Parameter window.
Path replacement performance counters allow you to track
when path replacement occurs. For information on performance counters, see the
Cisco Unified Serviceability Administration Guide.
For each call, the system generates more than one CDR for
the path replacement feature. One CDR gets generated for the caller at the
originating PINX; another CDR gets generated for the called party at the PINX
where path replacement is initiated.
Cisco IP Softphone user chooses to perform a consultive transfer to move a
call to another PINX, path replacement can occur; if the user performs a direct
(blind) transfer, path replacement cannot occur. For more information about
Cisco IP Softphone, see the
Cisco IP Softphone documentation that supports your version of the