DEFINITY Enterprise Communications Server Release 7
Maintenance for R7r
555-230-126 Issue 4
June 1999
Maintenance Object Repair Procedures
9-1077MMI-SYNC
9
MMI-SYNC
NOTE:
Refer to Chapter 5, ‘‘Alarms, Errors, and Troubleshooting’’ for MMCH
troubleshooting information.
Each Port Network (PN) must have a TN787D or later MMI circuit pack assig ned
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 circu it pack is
designated as the master s ynchronization source for all MMI circ uit 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 sy nchronizes to its internal clock , and there should be no servic e
disruption. A loss of sync hronization is usually the result of a circuit p ack failure.
The maintenance strategy is to switch the mast er 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 reporting 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 within th e PN are instructed to listen to this new signal, and the old
master stops providing the signal and now listens to the new mast er MMI. If an
MMI is physically removed from the system, 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 switc h is
not allowed for 15 minutes to avoid hyp eractive switching. I f all the MMIs have
alarms, then no switch is made.
MO Name (in
Alarm Log) Alarm
Level Initial Command to Run1
1. Where UU is the universal cabinet number (1 for PPN and 2-44 for EPN); C is the carrier designation
(for example, A, B, C, D, or E); SS is the address of the slot in the carrier where the circuit pack is
located (for example, 01, 02, ...); and pp is the two digit p ort number (01, 02, 03,...).
Full Name of MO
MMI-SYNC MINOR test board UUCSS l r# Multimedia Interface Circuit Pack