Table 10-1 Ssm Generation 1 Message Set; Table 10-2 Ssm Generation 2 Message Set - Cisco ONS 15454 Reference Manual

Chapter 10 Timing
10.3 Synchronization Status Messaging
Synchronization status messaging (SSM) is a SONET protocol that communicates information about the
quality of the timing source. SSM messages are carried on the S1 byte of the SONET Line layer. They
enable SONET devices to automatically select the highest quality timing reference and to avoid timing
loops.
SSM messages are either Generation 1 or Generation 2. Generation 1 is the first and most widely
deployed SSM message set. Generation 2 is a newer version. If you enable SSM for the ONS 15454,
consult your timing reference documentation to determine which message set to use.
Table 10-2 on page 10-3
Table 10-1
Message
PRS
STU
ST2
ST3
SMC
ST4
DUS
RES
Table 10-2
Message
PRS
STU
ST2
TNC
ST3E
ST3
SMC
ST4
DUS
RES
OL-9217-01
show the Generation 1 and Generation 2 message sets.
SSM Generation 1 Message Set
Quality Description
1 Primary reference source—Stratum 1
2 Synchronization traceability unknown
3 Stratum 2
4 Stratum 3
5 SONET minimum clock
6 Stratum 4
7 Do not use for timing synchronization
— Reserved; quality level set by user
SSM Generation 2 Message Set
Quality Description
1 Primary reference source—Stratum 1
2 Synchronization traceability unknown
3 Stratum 2
4 Transit node clock
5 Stratum 3E
6 Stratum 3
7 SONET minimum clock
8 Stratum 4
9 Do not use for timing synchronization
— Reserved; quality level set by user
10.3 10.3 Synchronization Status Messaging
Cisco ONS 15454 Reference Manual, R7.0.1
Table 10-1 and
10-3