DEFINITY ECS Release 8.2 Maintenance for R8.2csi
555-233-119 Issue 1
April 2000
Maintenance Objects
3-851MMI-SYNC
3
MMI-SYNC
NOTE:
Refer to ‘‘Troubleshooting Multimedia Call Handling (MM CH)’’ in Chapter 1
for MMCH troubleshooting information.
Each Port Network (PN) must have a TN787D or later MMI circuit pack assi gned
as the Multimedia Interface (MMI) mast er synchronization source for that PN. If
one or more MMI circuit pac k is administered in a PN, one MMI circ uit pack is
designated as the master s ynchronization source for all MMI ci rcuit packs within
that PN.
The MMI circuit pack g enerates a synchronization signal and puts that signal on
the TDM bus. Other MMI packs or any other c ircuit pack within a PN can listen to
this signal and “sync hronize up” to it. The first MMI circ uit pack inserted in a PN
is normally designated as the master. As subsequent MMI p acks are inserted,
they are instructed to listen and synchronize to the time-slot of the master MMI. In
the unlikely case of an MMI losing this reference, an up link message is sent from
the MMI circuit pac k that lost the signal to maintenance, whic h also clears the
“event” counter on this MMI with a d ownlink message. This forces the MMI circ uit
pack to return the current state of th e synchronization signal. If the signa l is still
lost, then the recovery algorithm is entered . Note that during this time, the MMI
circuit pack synchronizes to its internal cloc k, and there should be no s ervice
disruption. A loss of sync hronization is usually the result of a circuit p ack failure.
The maintenance strategy is to switch the ma ster source away from the bad p ack
to another healthy MMI circuit pac k within the PN.
A synchronization switch takes p lace if half or more of the MMI circuit p acks in a
PN report a loss of synchronization. For example, a PN with two MMIs repor ting a
loss of sync source switc hes immediately, three and four MMIs switch if two
report the loss, and so forth. A healthy MMI circuit pack b ecomes the master
synchronization source provid ing the signal on a new timeslot. The other MMI
circuit packs withi n the PN are instructed to listen to this new signal, and the old
master stops providing the signal and now listens to the new ma ster MMI. If an
MMI is physically removed from the s ystem, then the remaining MMIs report the
loss of synchronization. The first MMI with no alarms present b ecomes the new
master of that PN. Once a synchronization switc h has occurred, another swit ch is
not allowed for 15 minutes to avoid hyp eractive switching . If all the MMIs have
alarms, then no switch is made.
MO Name (in
Alarm Log)
Alarm
Level Initial Command to Run1
1. Where P is the port network number (1 for PPN); C is the carrier designation (for example, A, B, or
C); and SS is the address of the slot in the carrier where the circuit pack is located (for example,
01, 02,..., and so forth).
Full Name of MO
MMI-SYNC MINOR test board PCSS l r# Multimedia Interface Circuit Pack