Path Replacement
Path backup allows for a potentially added able affiliation to be established
between two parties in an alive call. In Cisco UCM, this can action afterwards a QSIG transfer
via a accompany or a aberration by advanced switching.
In a QSIG network, afterwards a alarm is transferred or forwarded to a buzz in a third PINX,
multiple access through several PINX(s) can abide for the call. Afterwards the alarm connects,
the aisle backup affection drops the affiliation to the alteration PINXs and creates
a new alarm affiliation to the absolute PINX. Calls that absorb assorted trunks (for
example, appointment calls) do not use aisle replacement. However, if you accept the
QSIG advantage from the Tunneled Protocol drop-down account and analysis the Path
Replacement Support analysis box for gatekeeper-controlled or non-gatekeeper-controlled
intercluster trunks (in the Cisco UCM Administration interface), aisle backup occurs
over the intercluster block and the added QSIG intercluster or PRI block that is acclimated to
transfer or alter the call.
It is important that you accept the new aisle accustomed by aisle backup is not
guaranteed to be added efficient. Rather, it is alone “likely.” The arrangement cartography and
route patterns in the arrangement actuate if and back the new aisle will be added optimal
than the old path. Aisle backup does not get invoked by the Cisco UCM in added situations,
such as a appointment call.
Figure 4-20 illustrates a aisle backup archetype area aisle backup replaces an
existing TDM ambit amid two parties on an alive alarm with a new one in adjustment to
use the TDM assets added efficiently.
Chapter 4: Performing Alarm Signaling over Digital Voice Ports 235
V V
Cluster A Cluster B
User A
DN: 1000
User C
DN: 3000
User B
DN: 2000
User A calls User B.
1
Switch over.
6
User B transfers to User C.
2
User B drops off.
3
Cluster C establishes
a new ambit to A.
5
Cluster A asks Cluster C
via Cluster B for path
replacement to DN 1000.
4
Figure 4-20 QSIG Aisle Replacement
The afterward accomplish alarm the arrangement of contest depicted in Figure 4-20:
Step 1. User A calls User B.
Step 2. User B transfers the alarm to User C.
Step 3. User B drops off the alarm by acute Transfer again.
Step 4. Cluster A sends a bulletin via B to C proposing that Cluster C should alarm DN
1000 for a aisle replacement.
Step 5. Cluster C establishes a new ambit to A.
Step 6. Cluster C and Cluster A “switch over” the alive alarm to use the new
connection.