Clock Source Quality Level Definitions; Figure 15: Using Ieee 1588V2 For Time Distribution - Alcatel-Lucent 7450 ESS-12 Configuration Manual

Clock Source Quality Level Definitions

The following clock source quality levels have been identified for the purpose of tracking network
timing flow. These levels make up all of the defined network deployment options given in
Recommendation G.803 and G.781. The Option I network is a network developed on the original
European SDH model; whereas, the Option II network is a network developed on the North
American SONET model.
In addition to the QL values received over SSM of an interface, the standards also define
additional codes for internal use. These include the following:
•
•
Within the SR/ESS, there is also an internal quality level of QL-UNKNOWN. This is used to
differentiate from a received QL-STU code but is equivalent for the purposes of QL selection.
Table 23: Synchronization Message Coding and Source Priorities
SDH interface
SyncE interafce in
SDH mode
0010 (prc)
0100 (ssua)
1000 (ssub)
7450 ESS OS Basic System Configuration Guide
QL INVx is generated internally by the system if and when an unallocated SSM value is
received, where x represents the binary value of this SSM. Within the SR/ESS all these
independent values are assigned as the singled value of QL-INVALID.
QL FAILED is generated internally by the system if and when the terminated network
synchronization distribution trail is in the signal fail state.
SSM value received on port
SONET Interface
SyncE interface in
SONET mode
0001 (prs)
0000 (stu)
0111 (st2)
0100 (tnc)
1101 (st3e)
1010 (st3/eec2)
E1 interface T1 interface (ESF)
0010 (prc) 00000100 11111111
(prs)
00001000 11111111
(stu)
00001100 11111111
(ST2)
0100 (ssua) 01111000 11111111
(TNC)
01111100 11111111
(ST3E)
1000 (ssub)
00010000 11111111
(ST3)
System Management
Internal
Relative
Quality Level
1. Best quality
2.
3.
4.
5.
6.
7.
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