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Cisco Transport Manager Release 6.0 User Guide
78-16845-01
Chapter 3 Building the Network
3.10.1 Synchronization Settings for the ONS 15310, ONS 15327, ONS 15454 SONET, and ONS 15600 SONET
Note Alarms relating to PM collection indicate that the load on the system is high. Reduce the load on the
system before proceeding.
3.10.1.1 Setting Up External or Line Timing for CTC-Based SONET NEs
Step 1 Select an ONS 15310, ONS 15327, ONS 15454 SONET, or ONS 15600 SONET NE and choose
Configuration > NE Explorer.
Step 2 In the node property pane, click the Timing tab. Fields shown depend on the NE that is selected.
Step 3 In the General Timing section of the General subtab, complete the following information:
• Timing Mode—Set to External if the NE derives its timing from a building integrated timing supply
(BITS) source wired to the backplane pins; set to Line if timing is derived from an OC-N card that
is optically connected to the timing node. A third option, Mixed, allows users to set external and
line timing references.
Caution Because mixed timing can cause timing loops, Cisco does not recommend its use. Use this mode with
care.
Note The Mixed option is not applicable to the ONS 15600 SONET.
• SSM Message Set—Choose the message set level supported by the network. If a Generation 1 node
receives a Generation 2 message, the message will be mapped down to the next available Generation
1. For example, an ST3E message becomes an ST3.
• Revertive—If checked, the NE reverts to a primary reference source after the conditions that caused
it to switch to a secondary timing reference are corrected.
• Reversion Time—If Revertive is checked, indicate the amount of time that the NE will wait before
reverting back to its primary timing source.
Table 3-19 SSM Generation 2 Message Set
Message Quality Description
PRS 1 Primary reference source—Stratum 1
STU 2 Sync traceability unknown
ST2 3 Stratum 2
TNC 4 Transit node clock
ST3E 5 Stratum 3E
ST3 6 Stratum 3
SMC 7 SONET minimum clock
ST4 8 Stratum 4
DUS 9 Do not use for timing synchronization
RES — Reserved; quality level set by user