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Hierarchy Level


For ACX Series routers operating with Synchronous Ethernet, configure the quality level (QL) for a timing source so that the router can know the best available source with which to synchronize. The QL specifies the expected accuracy level of the clock and is transmitted across the network through Synchronization Status Messages (SSMs) over the Ethernet Synchronization Message Channel (ESMC).

The quality level options are valid depending on the configured network-option; option-1 or option-2 at the [edit chassis synchronization] hierarchy level.

Both option-1 and option-2 SSM quality levels (QL) are supported:

  • For option-1, QL must be configured for external clocks (gps or bits) whether or not QL is enabled.

  • For option-2, the default QL for external clocks is QL_STU whether or not QL is enabled.


prc—Timing quality of a primary reference clock (option-1 only).

prs—Clock traceable to a primary reference source (option-2 only).

sec—Timing quality of an SDH equipment clock (option-1 only).

smc— Clock traceable to a self-timed SONET (option-2 only).

ssu-a—Timing quality of a type I or IV client clock (option-1 only).

ssu-b—Timing quality of a type VI client clock (option-1 only).

st2—Clock traceable to Stratum 2 (option-2 only).

st3—Clock traceable to Stratum 3 (option-2 only).

st3e—Clock traceable to Stratum 3E (option-2 only).

st4—Clock traceable to Stratum 4 free-run (option-2 only).

stu—Clock traceable to an unknown quality (option-2 only).

tnc—Clock traceable to a transit node clock (option-2 only).

Required Privilege Level

interface—To view this statement in the configuration.

interface-control—To add this statement to the configuration.

Release Information

Statement introduced in Junos OS Release 12.2.