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MERLIN LEGEND Communications System Release 6.1 | Issue 1 |
Network Reference | August 1998 |
5 Network Management |
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General Programming in Private Networks | Page |
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source is a Digital Signal 1 (DS1) facility connected to a
Clock synchronization derived from the PSTN, either via PRI or BRI facilities, is always preferable to a clock source that is provided by a digital tandem facility that is not connected to the PSTN. Private networked systems, however, may not have an
In a private network with three or more systems, it is best if all clock sources for the private network are on either a hub system (star configuration) or a system that connects two other switches (series configuration). If the primary clock source is not functioning, then a secondary or tertiary source on such a system can serve either all other systems in the private network or two other systems in a private network. The following examples illustrate how clock synchronization can be implemented in a private network.
PSTNPSTN
| 100D |
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| tandem | |
System A | ||||
PRI |
100D
100D100D
tandem 100D
100D
PRI
Primary: Loop | System B | System C |
Secondary: Local | Primary: PSTN Loop | Primary: Loop B |
Tertiary: ______ | Secondary: Local C | Secondary: PSTN Loop |
| Tertiary: Local A | Tertiary: Local B |
1.If tandem digital facilities link the systems in a private network and a non- local system is connected to functional digital PSTN facilities, a system with no digital PSTN facilities assigns its digital tandem lines as loop to derive the clock source from the system connected at the other end of the link. Synchronization is derived from the PSTN connection on one private networked system. The system connecting to the PSTN also assigns its clock source as loop because its clock source is at the far end of the PSTN