Itu Ssm Quality Level Definitions - Symmetricom TimeProvider 1000 User Manual

Chapter 1 Overview of the TimeProvider
Synchronization Status Messages (SSMs)
Table 1-4. ANSI SSM Quality Level Definitions (Continued)
SONET Minimum Clock traceable
(20 ppm clock)
Stratum 4 traceable (32 ppm clock)
Do Not Use for synchronization
Table 1-5. ITU SSM Quality Level Definitions
Primary Reference Clock
Transit Node
Local Node
Synchronization Equipment Clock
Do Not Use for synchronization
The TimeProvider handles SSMs in accordance with T1X1.3 TR33, T1.101-1999,
GR-253, and 379-CORE.
Input SSMs
The TimeProvider extracts and decodes the SSM (if present) on the available
inputs. Using this information, the TimeProvider can automatically select the input
with the higher quality level.
You can manually provision the input quality level for those signals that do not have
SSM information or you can provision INP1 and INP2 to read the SSM on the input;
in either case the quality level of the reference input becomes the system's quality
level, which is passed through to the outputs in the output SSM. If the IOC enters
the Free-run or Holdover mode, the system's quality level is determined by the
CLKTYPE parameter for the local oscillator on the selected IOC module. You can
provision the CLKTYPE parameter to Type I, Type II, ST2, or ST3E.
Output SSMs
You must provision the TimeProvider's outputs according to the type of SSM
operation you are using:
For ANSI SSM operation, set the output type to Extended SuperFrame (ESF) for
ANSI SSM operation
For ITU SSM operation, set the output type to Channel Associated Signaling
(CAS) with CRC4 framing (this setting is automatically set when you enable SSMs)
38 TimeProvider User's Guide
Description
Description
Quality Level Abbreviation
7 SMC
8 ST4
9 DUS
Quality Level Abbreviation
2 PRC
4 SSUT
8 SSUL
11 SEC
15 DNU
097-58001-02 Revision C – August 2005