EXFO IQS-8100 Series Transport Blazer for IQS-600 - Manual (Page 636)

Glossary
622 IQS-8100 Series Transport Blazer
SONET - Section Overhead (SOH)
SONET - Section Overhead (SOH)
The section contains overhead information (SOH) used by all SONET
equipment along a network path, including signal regenerators.
A1 and A2: Framing
A1 and A2 provide frame alignment of each STS-1 frame within a
composite signal (STS-1 to STS-n). They must appear in every STS-1 of a
composite signal. The value is hexadecimal F628.
J0: Trace
The J0 (Trace) byte is used to trace the origin of an STS-1 frame as it travels
across the SONET network. This byte is only defined for the first STS-1
frame of a composite signal STS-1 to STS-n (STS-1 of an electrical or OC-N
signal).
Z0: Growth
The Z0 (Growth) byte was used to uniquely identify the STS in question.
This byte had to be defined in every STS-1 to STS-n frame of a composite
signal. For speed reasons, a Section Trace is a much better use of this byte.