Agilent Technologies J3972A - Manual (Page 171)

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Payload Type Indicator (PTI)
The Payload Type Indicator (PTI) is a 3-bit field that defines the contents of an
ATM cell. The first bit determines if the cell is user data (0) or network signaling
information (1). The second bit determines if there is no congestion (0) or
congestion (1). The third bit identifies the SDU type (if it is a user cell) or the
OAM type (if it is a control cell).
PTI - Explanation
000 - User data cell - no congestion - SDU Type 0
001 - User data cell - no congestion - SDU Type 1
010 - User data cell - congestion - SDU Type 0
011 - User data cell - congestion - SDU Type 1
100 - Segmented OAM F5 flow related cell
101 - End-to-End OAM F5 flow related cell
110 - reserved for future use
111 - reserved for future use
PDH
Plesiochronous Digital Hierarchy
PFEBE
Path Far End Block Error
Physical Layer (PL)
Level 1 of the seven level OSI reference model defined by ISO. The physical
layer provides for the physical transportation of cells across the network. It
consists of physical medium dependent (PMD) and transmission convergence
(TC) sublayers. Important categories are PDH, SDH and the physical media used
on local premises for LANs.
Physical Layer Convergence Protocol (PLCP)
The Physical Layer Convergence Protocol (PLCP) is used to map cells into the
DS3 bit stream. There are 12 cells in a PLCP frame. Each cell is preceded by a 2-
byte framing pattern (A1,A2) to enable the receiver to synchronize to the cells.
After the framing pattern is an indicator consisting of one of 12 fixed bit patterns
used to identify the cell location within the frame (POI). This is followed by a