RS8234EBGC Mindspeed Technologies, RS8234EBGC Datasheet - Page 164

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

6.0 Traffic Management
6.1 Overview
6.1.2 ABR Flow Control Manager
Figure 6-2. ABR Flow Control
6-4
ABR Flow Control
Templates
Manager
ABR
UPDATE
RATE
The RS8234 implements the ATM Forum ABR flow control algorithms, referred
to in the aggregate as ABR by this document. The ABR service category
effectively allows zero cell loss transmission through an ATM network, by
regulating transmission based upon network feedback. The ABR algorithms
regulate the rate of each VCC independently.
diagram of the RS8234’s ABR feedback control loop.
ABR Flow Control Manager. This state machine processes the feedback
information according to per-VCC parameters and user programmable ABR
templates, both located in SAR shared memory. These templates define ABR
service parameters and policies for groups of VCCs.
Scheduler with an updated rate. Under the policy imposed by the template, the
rate complies with the TM 4.1 Source Behavior specifications. Until the next
update, the Cell Scheduler uses this rate to dynamically schedule the connection.
ABR algorithm in a hardware state machine. However, to provide flexibility
against minor changes in the immature TM 4.1 specification, the state machine is
programmable through Mindspeed-supplied ABR templates. These templates,
resident in SAR shared memory, also provide a policy tuning mechanism for
interoperability and performance. Separate groups of VCCs can be assigned to
application optimized templates according to their path through the network.
Network feedback is received by the reassembly coprocessor and routed to the
Once the feedback is processed, the Flow Control Manager provides the Cell
For optimal performance, the ABR Flow Control Manager implements the
Cell Scheduler
Parameters
and Priority
Schedule
Dynamic
Per-VCC
Table
Mindspeed Technologies
VCC_INDEX
ATM ServiceSAR Plus with xBR Traffic Management
Segmentation
Coprocessor
Coprocessor
Reassembly
™
Figure 6-2
Cell Stream
Feedback
ABR
RM Cell
shows a high level block
28234-DSH-001-B
Network
ATM
RS8234
100074_041