Agilent Technologies J3972A, J3919A Payload Type Indicator PTI, Pdh, Pfebe, Physical Layer PL

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

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