S/UNI®-JET Data Sheet
Released
Figure 11 E1 PLCP Frame Format
A1
A1
A1
A1
A1
A1
A1
A1
A1
A1
A2
A2
A2
A2
A2
A2
A2
A2
A2
A2
P9
P8
P7
P6
P5
P4
P3
P2
P1
P0
Z4
Z3
Z2
Z1
F1
B1
G1
M2
M1
C1
ATM Cell
ATM Cell
ATM Cell
ATM Cell
ATM Cell
ATM Cell
ATM Cell
ATM Cell
ATM Cell
ATM Cell
PLCP
Frame Rate
2.375 ms
Framing
POH
53 octets
(3 octets)
The E1 PLCP frame provides the transmission of 10 ATM cells every 2.375 ms. Thirty of the
thirty-two available E1 channels are used for transporting the PLCP frame. The remaining two
channels are reserved for E1 framing and signaling functions. The PLCP frame is octet aligned to
the channel boundaries in the E1 frame. The PLCP frame is aligned to the 125 µs E1 frame (the
A1 octet of the first row of the PLCP frame is inserted in timeslot 1 of the E1 frame).
13.3.1
PLCP Path Overhead Octet Processing
Table 34 PLCP Overhead Processing
Overhead Field
A1, A2:
Transmit Operation
Receive Operation
Inserts the PLCP frame alignment
Searches the receive stream for the PLCP
frame alignment pattern. When the pattern has
been detected for two consecutive rows, along
with two valid, and sequential path overhead
identifier octets, the S/UNI-JET declares in-
frame.
pattern (F628H)
Frame Alignment
Pattern
Note: The ATM cell boundaries are implicitly
known when the PLCP frame is located, thus
cell delineation is accomplished by locating the
PLCP frame. When errors are detected in both
octets in a single row, or when errors are
detected in two consecutive path overhead
identifier octets, the S/UNI-JET declares an
OOF defect. The LOF defect is an integrated
version of the OOF defect state.
PO-P11:
Inserts the path overhead identifier Identifies the PLCP path overhead bytes by
codes in accordance with the
PLCP frame alignment. See Table
35.
monitoring the sequence of the POI bytes.
Path Overhead
Identifier
Z1-Z6:
These octets are unused and are
These octets are ignored and are extracted on
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