RS8234 Mindspeed Technologies, RS8234 Datasheet - Page 9

• Manufacturer Part Number: RS8234
• Description: Atm Servicesar Plus With Xbr Traffic Management
• Manufacturer: Mindspeed Technologies

28234-DSH-001-B
1.0 RS8234 Product Overview
1.1 Introduction
The RS8234 Service Segmentation and Reassembly Controller (ServiceSAR)
delivers a wide range of advanced ATM, AAL, and service-specific features in a
highly integrated CMOS package.
capabilities of accelerating specific protocol interworking functions. These
features include, for example, Virtual FIFO segmentation of circuit-based
Constant Bit Rate (CBR) traffic, and Frame Relay Early Packet Discard (EPD)
based on the Discard Eligibility (DE) field.
Two examples of these features include Generic Flow Control (GFC), and echo
suppression of multicast data frames on Emulated LAN (ELAN) channels.
complies with ATM Forum Traffic Management specification TM 4.1. The
RS8234 provides traffic shaping for all service categories:
The internal xBR Traffic Manager automatically schedules each VCC according
to user assigned parameters.
congestion. The host manages the RS8234 terminal using an efficient architecture
employing write-only control and status queues. For example, the host submits
data for transmit by writing buffer descriptor pointers to one of 32 Transmit
Queues. These entries can be thought of as task lists for the ServiceSAR to
perform. The RS8234 reports segmentation and reassembly status to the host by
writing entries to segmentation and reassembly status queues, which the host then
further processes. This architecture lessens the control burden on the host system
and minimizes Peripheral Component Interconnect (PCI) bus utilization by
eliminating reads across the PCI bus from host control activities.
Some of the RS8234 service-level features provide system designers with
Other service-level functions enable network level functionality or topologies.
In addition to meeting the requirements contained in UNI 3.1, the RS8234
• CBR, Variable Bit Rate (VBR) — both single and dual leaky bucket
• Unspecified Bit Rate (UBR)
• Available Bit Rate (ABR)
• GFC — both controlled and uncontrolled flows
• Guaranteed Frame Rate (GFR), i.e., guaranteed Minimum Cell Rate
The RS8234’s architecture is designed to minimize and control host traffic
(MCR) on UBR Virtual Channel Connections (VCCs)
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