DEFINITY Enterprise Communications Server Release 7
Maintenance for R7r
555-230-126 Issue 4
June 1999
Maintenance Object Repair Procedures
9-246ATM-SYNC (ATM Synchronization)
9
ATM-SYNC (ATM Synchronization)
This section discusses intra-swit ch synchronization maintenanc e and the
hardware and software components that p rovide a common reference freq uency
for reliable digital c ommunication among the G3r system, the ATM switch, and
other PBXs, Central Offices (COs) or Customer-Premises Equipment (CPE).
Circuit packs involved in synchronization includ e:
■TN768, TN780, or TN2182 Tone/Clock
■TN722, TN767, and TN464 DS1 Interfaces (all suffixes)
■TN2305/6 (R7.1) and TN2238 (R6.3) ATM Expansion Interface (multimode
fiber)
Synchronization is achieved betwe en the Processor Port Network (PPN) and the
Expansion Port Networks (EPNs) through the ATM port network connectivity (ATM
PNC) between the networks. Depending on the network synchronization plan
and the status of synchronization sourc es, the system timing reference may be:
■The clock circuit p ack on the ATM switch
■A DS1 or UDS1 interface circuit pack-tap ped T1 input signal c onnected to
the ATM switch clock circuit
■An OC-3 interface circuit p ack on the ATM switch
Stratum 4 synchronization extracts timing infor mation directly from
■A DS1 or UDS1 reference
■An OC3 referenc e
■The ATM switch clock
For further information about synchronization inc luding network sync hronization,
see

AT&T Network and Data Connectivity

.

Stratum 4 Synchronization

Systems may have primary and sec ondary synchronization referenc es
(DS1/UDS1 interface circuit pac ks or ATM-Switch) when using Stratum 4
synchronization.
If the primary synchronization reference in Figure 9-12 is providing a valid timing
signal, then the flow of system synchronization wo uld travel from the DS1
interface circuit p ack in the EPN to the ATM switch. The primary DS1 interface
MO Name (in
Alarm Log) Alarm
Level Initial Command to Run Full Name of MO
ATM-SYNC MINOR d isplay errors ATM Synchronization
ATM-SYNC WARNING test synchronization ATM Synchronization