S/UNI®-JET Data Sheet
Released
The DS1 PLCP frame provides the transmission of 10 ATM cells every 3 ms. The PLCP frame is
octet aligned to the framing bit in the DS1 frame; there is no relationship between the start of the
PLCP frame, and the start of the DS1 frame. A trailer is inserted at the end of each PLCP frame.
The number of octets inserted is always six, and cannot be varied.
Figure 10 G.751 E3 PLCP Frame Format
A1
A1
A1
A1
A1
A1
A1
A1
A1
A2
A2
A2
A2
A2
A2
A2
A2
A2
P8
P7
P6
P5
P4
P3
P2
P1
P0
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
PLCP
Frame Rate
125 µs
Trailer
Framing
17,18,19,20, or 21
octets
POH
53 octets
(3 octets)
The G.751 E3 PLCP frame provides the transmission of 9 ATM cells every 125 µs. The PLCP
frame is octet aligned to the 16 overhead bits in the ITU-T Recommendation G.751 E3 frame;
there is no relationship between the start of the PLCP frame, and the start of the E3 frame. A
trailer is inserted at the end of each PLCP frame. The number of octets inserted is nominally 18,
19, or 20, and is based on the number of E3 overhead octets (4, 5, or 6) that have been inserted
during the PLCP frame period. The nominal octet stuffing can be varied by ±1 octet to allow the
E3 PLCP frame to be locked to an external 8 kHz reference. Thus the trailer can be 17, 18, 19, 20,
or 21 octets in length.
Proprietary and Confidential to PMC-Sierra, Inc., and for its Customers’ Internal Use
Document ID: PMC-1990267, Issue 3
263
PMC [ PMC-SIERRA, INC ]
