Avaya S8700 - Page 2232

Maintenance-Object Repair Procedures
555-233-143
8-1510 Issue 1 May 2002
This creates a hierarchy where the master EPN receives timing from the public
network, and every other EPN derives its timing from the master through the CSS.
See Figure 8-86.
Figure 8-86. Traditional Sync Operation
Typically, a pair of interfaces from the public network are configured — one as a
primary and one as a secondary. The IPSI/Tone-Clock in the Master PN can:
■ Lock onto either interface
■ Switch between them in the event of a failure
In the event of a dual failure, the Tone-Clock in the master PN can generate its
own timing and keep every PN synchronized. However, these PNs would not be
synchronized with any other public-network interfaces that exist in any of the PNs.
When a center stage is implemented via an ATM network, it is possible to obtain
timing from the ATM network. For more information, See ‘‘ATM-SYNC (ATM
Synchronization)’’ on page 8-264.
Clock Synchronization
NOTE:
Stratum-3 clocking is not available for an EPN where the Tone-Clock
function is supplied by either a:
■ TN2312 IPSI circuit pack’s Tone-Clock circuit
■ TN2182 Tone-Clock circuit pack
This section discusses synchronization with Stratum-3 and -4 clocking devices.
Master
PN
Center
Stage
Switch
Slave
PN
Slave
PN
Slave
PN
Public
Network
Primary
Secondary