MC92500ZQ Ver la hoja de datos (PDF) - Motorola => Freescale

Número de pieza

componentes Descripción

Fabricante

MC92500ZQ

ATM Cell Processor

Motorola => Freescale 

1.2 ATM Network Applications

The MC92500, an Asynchronous Transfer Mode cell-

processing device, is ideally suited for use in the inter-

face between a PHY-layer device and an ATM switch

fabric. The primary application of the MC92500 is ATM-

layer cell processing and routing.

Figure 3 illustrates a typical ATM line card using the

MC92500 device. The MC92500 uses an external

memory for storing the ATM virtual connections of the

cells it processes. In addition, the MC92500 offers an

option to utilize an external address compression de-

vice accessed via the same external memory bus.

The microprocessor is used for configuration, control

and status monitoring of the MC92500 and is responsi-

ble for initializing and maintaining the external memory.

The MC92500 is the master of the external memory

bus. At regular intervals the MC92500 allows the micro-

processor to access the external memory for updating

and maintenance.

System RAM can also be located on the line card. The

MC92500 can support a DMA device to allow efficient

data transfer to this RAM without processor interven-

tion.

The physical interface (PHY-IF) implements the physi-

cal layer functions of the B-ISDN Protocol Reference

Model.This includes the physical medium dependent

functions required to transport ATM cells between the

ATM user and the ATM switch (UNI) or between two

ATM switches (NNI). The cells are transferred between

the physical interface and the MC92500 using the

UTOPIA standard.

The MC92500 implements B-ISDN UNI/NNI ATM-layer

functions required to transfer cells to and from the

switch over virtual connections. These functions

include usage enforcement, address translation, and

Operation and Maintenance (OAM) processing.The

MC92500 provides context management for up to 64K

Virtual Connections (VCs). The VCs can be either

Virtual Path Connections (VPCs) or Virtual Channel

Connections (VCCs). ATM cells belonging to a

particular VCC on a logical link have the same unique

Virtual Path Identifier/Virtual Channel Identifier,

(VPI/VCI) value in the cell header. Similarly, cells

belonging to a particular VPC on the same logical link

share a unique VPI.

RRAAMM

µµPP

DDMMAA

EMExextmte-rMonrEayMl

ExtEexrntal

AdAddredsrs

ComCporemspsion

Microprocessor

Bus

Clock

Recovery

LINE CARD

PPPHHHYY-YI-FI-FIF

External

Memory

Bus

MC92500

to switch

from switch

MOTOROLA

4

Figure 3. Typical MC92500 Line Card Application

MC92500

Share Link: