Alcatel-Lucent 7950 XRS Series, Configuration Manual

Page: 247 / 502

System Management
7950 SR OS Basic System Configuration Guide Page 247
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:
• 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 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.
Within the , 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.