VeEX MPA, User Manual

Page: 376 / 842

SONET Tab
376
Unit Reports Loss of Signal
A Loss of Signal (LOS) occurs when the unit detects an all-zeros pattern for 100
milliseconds or greater on the incoming SONET signal.
If an LOS is present, verify the receive signal strength as indicated by RX in the
LEDs/Quick Status area of the touch screen.
Refer to the SFP Info screen for minimum RX power level.
Related Topics:
Unit reports Loss of Signal (LOS)
What causes a B1 error?
What causes a B2 error?
What causes a B3 error?
What causes an AIS alarm?
What causes an RDI alarm?
How to Insert Errors
How to Insert Alarms
What Causes a B1 Error?
SONET uses the B1 byte of the Section Overhead to detect parity errors on the
incoming SONET signal.
A B1 error occurs when a parity error is detected at the Section layer of the incoming
SONET signal. The parity error is known as a Bit Interleaved Parity, 8-bit (BIP-8). The
B1 byte, which is part of the Section Overhead, contains 8 bits used to calculate even
parity. Any error that occurs within those 8 bits is considered to be a B1 error.
A B1 error is also known as a Section Code Violation (CV-S). It performs error
monitoring by running an even parity check on the previous SONET frame.
MPA_e_manual_D07-00-129P_RevA00