Clock Source Quality Level Definitions - Alcatel-Lucent 7450 Basic System Configuration Manual

Network Synchronization
If the port is a fixed copper Ethernet port and in 1000BASE-T mode of operation, there is a
dependency on the 802.3 link timing for the Synchronous Ethernet functionality (refer to
ITU-T G.8262). The 802.3 link Master-Slave timing states must align with the desired
direction of Synchronous Ethernet timing flow. When a fixed copper Ethernet port is
specified as an input reference for the node or when it is removed as an input reference for
the node, an 802.3 link auto-negotiation is triggered to ensure the link timing aligns properly.
The SSM of Synchronous Ethernet uses an Ethernet OAM PDU that uses the slow protocol
subtype. For a complete description of the format and processing see ITU-T G.8264

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:
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.
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• 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. All of 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.
Basic System Configuration Guide