Technical data

TraverseEdge 2020 Applications and Engineering Guide, Chapter 8: Node Synchronization
Release 5.0.x Turin Networks Page 8-5
NOTE: The derived DS1 signals must be the same format (SF or ESF) as the external timing
(BITS) input. Also, the derived DS1 signals can not source timing derived from an OC-n interfaces
in an optical tributary shelf or the external timing (BITS) input.
8.2.4 Synchronization Status Messages
Synchronization status messages are passed via the upper nibble (bits 5 to 8) of the S1 byte of the SONET
line overhead and as bit-oriented messages in the Extended Superframe Format (ESF) data line of DS1 sig-
nals. These messages contain clock quality information that allows TE-2020s to select the most suitable
synchronization reference from the set of available references. The purpose of these messages is to allow
the TE-2020 to reconfigure its synchronization references autonomously while avoiding the creation of
timing loops. Table 8-1 lists the synchronization status messages that have been defined for the S1 byte
and the ESF DS1 format.
NOTE: The ESF synchronization status messages are transmitted right most bit first.
Table 8-1 Synchronization Status Message Definitions
Description Acro-
nym
Quality
Level
DS1 ESF Data Link
Code Word
S1 Bits
[5678]
Stratum 1 Traceable PRS 1 0000 0100 1111 1111 0001
Synchronized
Traceability Unknown
STU 2 0000 1000 1111 1111 0000
Stratum 2 Traceable ST2 3 0000 1100 1111 1111 0111
Transit Node Clock Traceable TNC 4 0111 1000 1111 1111 0100
Stratum 3E Traceable ST3E 5 0111 1100 1111 1111 1101
Stratum 3 Traceable ST3 6 0001 0000 1111 1111 1010
SONET Minimum Clock Traceable SMC 7 0010 0010 1111 1111 1100
Stratum 4 Traceable ST4 8 0010 1000 1111 1111 N/A
DO NOT USE for Synchronization DUS 9 0011 0000 1111 1111 1111
Reserved for Network
Synchronization Use
PNO Provisionable
by Network
Operator
0100 0000 1111 1111 1110