DS3181/DS3182/DS3183/DS3184
177
Figure 10-45. MA Byte Format
RDI - Remote Defect Indicator
REI - Remote Error Indicator
SL - Signal Label
MI - Multi-frame Indicator
TM - Timing Marker
RDI
REI
SL
MI
TM
MSB
1
LSB
8
Table 10-36 shows the function of each overhead bit in the DS3 Frame.
Table 10-36. G.832 E3 Frame Overhead Bit Definitions
BYTE
DEFINITION
FA1, FA2
Frame Alignment bytes
EM
Error Monitoring byte
TR
Trail Trace byte
MA
Maintenance and Adaptation
byte
NR
Network Operator byte
GC
General-Purpose
Communication Channel byte
FA1 and FA2 are the Frame Alignment bytes. EM is the Error Monitoring byte used for path error monitoring. TR is
the Trail Trace byte used for end-to-end connectivity verification. MA is the Maintenance and Adaptation byte used
for far-end path status and performance monitoring.
NR is the Network Operator byte allocated for network operator maintenance purposes. GC is the General-Purpose
Communications Channel byte allocated for user communications purposes.
10.10.8.2 Transmit G.832 E3 Frame Generation
G.832 E3 frame generation receives the incoming payload data stream, and overwrites all of the E3 overhead byte
locations.
The first two bytes of the first row in the frame are overwritten with the frame alignment bytes FA1 and FA2, which
have a value of F6h and 28h respectively.
The first byte in the second row of the frame is overwritten with the EM byte which is a BIP-8 calculated over all of
the bytes of the previous frame after all frame processing (frame generation, error insertion, overhead insertion,
and AIS generation) has been performed. The first byte in the third row of the frame is overwritten with the TR byte
which is input from the transmit trail trace controller.
The first byte in the fourth row of the frame is overwritten with the MA byte (see
Figure 10-45), which consists of the
RDI bit, REI bit, payload type, multiframe indicator, and timing source indicator.
The RDI (remote defect indicator) bit can be generated automatically, set to one, or set to zero. The RDI source is
programmable (automatic, 1, or 0). If the RDI is generated automatically, it is set to one when one or more of the
indicated alarm conditions are detected on the receive side, and set to zero when all of the indicated alarm
conditions are absent. Automatically setting RDI on LOS, LOF, or AIS is individually programmable (on or off).
The REI (remote error indicator) bit can be generated automatically or inserted from a register bit
(E3G832.TCR.TFEBE). The REI source is programmable (automatic or register bit). If REI is generated