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Network Synchronization

Introduction

Before running the CSP, synchronize T1, E1, and J1 spans to the network. Use the Synchronization Priority List Configure message to configure a prioritized list of clock sources. The CSP uses this list when it selects a synchronization clock source.

The default priority for synchronization resources is as follows:

1. External Reference Clock 1 (Primary)

2. External Reference Clock 2 (Secondary)

3. Loop Timing 1 (Primary)

4. Loop Timing 2 (Secondary)

5. Free Running clock (Internal)

The CSP continuously monitors all synchronization clock sources and uses the highest priority clock source currently available. For example, if you use the default configuration above, the CSP first determines if the Primary External Reference Clock is available. If it is not available, the CSP determines if the Secondary reference Clock is available. The CSP continues to check each source, in succession, until it finds an available source. When a higher priority source becomes available, the CSP automatically changes to the higher priority clock source.

Clock Sources

Descriptions of the synchronization sources are as follow:

External Reference Clock

Reference Timing is generated by an external clock source to the Matrix Controller card through the Matrix Controller I/O. One of the Matrix Controller I/O cards function is to take in a external reference clock and provide that timing to the Matrix Controller card which in turns uses that clock for system timing on the bus.The Matrix controller I/O card can sync to the following reference clocks 1.544 Mbps or 2.048 Mbps.

Loop Timing

Loop timing synchronizes the system to an incoming T1, E1, and J1 span. You must first designate which span you want to use to extrapolate the clock. Use the Loop Timing Configure message after you assign spans.

Free Running Clock

Free running timing is based on the internal clock source of 2.048 Mbps. Free running timing is for test environments only. Do not use this timing method for network operations. You can determine the current active timing by performing a synchronization priority list query.

System Time

You must use the Time Set message to set the system time. The CSP uses the system time to timestamp fault log entries.

Poll Interval

Two seconds is the default interval between Poll messages sent from the Matrix Controller to the host. You can use the Poll Interval Configure message to change the Poll interval.

Loop Timing

Configure Loop Timing to derive time from a T1 or E1 span.

Card Configuration

Card configuration includes the following:

• Line Cards

• DSP resources

• Common Channel Signaling Cards

Digital communications link - voice, data, and video at a 1.544 Mbps rate (24 64 Kbps channels)
A digital communications link - voice, data, and video at a 2.048 Mbps rate; 30B/2D or 31B/1D (ISDN); non-North American version of T1.
Digital Signal Processor
CCS. Network architecture using SS7 protocol for the exchange of information between telecommunications nodes and networks on an out-of-band basis.