PM7347 datasheet(263/341 Pages) PMC

263 / 341 page

S/UNI®-JET Data Sheet

Released

Proprietary and Confidential to PMC-Sierra, Inc., and for its Customers’ Internal Use

263

Document ID: PMC-1990267, Issue 3

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

Trailer

17,18,19,20, or 21

octets

ATM Cell

PLCP

Frame Rate

125 µs

53 octets

POH

Framing

(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.

PM7347 Datasheet(PDF) 263 Page - PMC-Sierra, Inc