Cisco Systems 15454 11.13 Path Signal Label, C2 Byte

11-24
Cisco ONS 15454 Reference Manual, R7.0
78-17191-01
Chapter 11 Circuits and Tunnels
11.13 11.13 Path Signal Label, C2 Byte
If the string received at a circuit drop port does not match the string the port expects to receive, an alarm
is raised. Two path trace modes are available:
• Automatic—The receiving port assumes that the first string it receives is the baseline string.
• Manual—The receiving port uses a string that you manually enter as the baseline string.
11.13 Path Signal Label, C2 Byte
One of the overhead bytes in the SONET frame is the C2 byte. The SONET standard defines the C2 byte
as the path signal label. The purpose of this byte is to communicate the payload type being encapsulated
by the STS path overhead (POH). The C2 byte functions similarly to EtherType and Logical Link Control
Table 11-9 ONS 15454 Cards Capable of J1 Path Trace
J1 Function Cards
Transmit and Receive CE-Series
DS1-141
DS1N-14
DS1/EC1-56
DS3-12E
DS3i-N-12
DS3/EC1-48
DS3N-12E
DS3XM-6
DS3XM-12
FC_MR-4
G-Series
ML-Series
1. J1 path trace is not supported for DS-1s used in VT circuits.
Receive Only EC1-12
OC3 IR 4/STM1 SH 1310
OC3 IR 4/STM1 SH 1310-8
OC12/STM4-4
OC48 IR/STM16 SH AS 1310
OC48 LR/STM16 LH AS 1550
OC192 SR/STM64 IO 1310
OC192 LR/STM64 LH 1550
OC192 IR/STM SH 1550
OC192-XFP