RS8234EBGC Mindspeed Technologies, RS8234EBGC Datasheet - Page 189

• Manufacturer Part Number: RS8234EBGC
• Description: RS8234EBGC ATM XBR SAR
• Manufacturer: Mindspeed Technologies

RS8234
ATM ServiceSAR Plus with xBR Traffic Management
6.3.7 Rate Decisions and Updates
28234-DSH-001-B
6.3.7.2 Rate Adjustment
6.3.7.1 ABR Traffic
Overview
Shaping
The RS8234 schedules ABR VCCs as a single leaky bucket GCRA channel, but
the rate is subject to continual adjustment. At initialization, the Host assigns flow
controlled VCCs I and L parameters corresponding to the negotiated ICR. The
Cell Scheduler rate-shapes the initial traffic according to these GCRA
parameters. This shaped cell stream includes in-rate Forward and Backward RM
cells.
ABR Flow Control Manager overwrites the I and L parameters in the
SCH_STATE of the VCC. The updated rates fall within the range of MCR and
PCR, which are specified on a per-connection basis.
The RS8234 dynamically adjusts the rate of transmission for ABR VCCs based
upon network feedback, individual VCC parameters, and the current transmission
rate. The ABR Flow Control Manager uses all of these inputs to calculate the
ACR of the connection. This ACR corresponds to I and L GCRA parameters. The
RS8234 updates the I and L parameters of the VCC with the new ACR I and L
values.
types of events—the reception of a Backward RM cell or the transmission of a
Forward RM cell. The decision process is unique for each event type.
NOTE:
When feedback from the network results in flow control rate adjustments, the
The Flow Control Manager updates the transmission rate in response to two
Note that both of these event types may occur in one cell slot. In this case,
the RS8234 makes both decisions before updating ACR.
Mindspeed Technologies
™
6.3 ABR Flow Control Manager
6.0 Traffic Management
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