pxf4336 Infineon Technologies Corporation, pxf4336 Datasheet - Page 83

• Manufacturer Part Number: pxf4336
• Description: Abm Premium Atm Buf Fer Manager
• Manufacturer: Infineon Technologies Corporation

3.4.2.2.2 Round Robin Scheduler
The round robin scheduler keeps all of its input queues, which have cells to send in a
FIFO structured list. The queue at the head of the list is allowed to send one cell and is
then rescheduled at the end of the list. Thereby, the available bandwidth is divided
equally among those queues which have cells to send.
3.4.2.2.3 Weighted Fair Queueing Scheduler
Rate guarantees for non real-time connections are achieved with the WFQ scheduler.
The WFQ scheduler has an arbitrary number of input queues with a weight factor
assigned to each of them. The absolute values of the weights are irrelevant, only the
relative values count. See
weight factors.
The WFQ scheduler has the following important properties:
• It is work conserving, i.e. the available bandwidth is always used completely as long
• It provides a fair distribution of the available bandwidth in proportion to the assigned
• It guarantees minimum rates to queues as long as the sum of the configured minimum
The properties above make the WFQ scheduler particularly useful for bursty connections
with start/stop behavior. The WFQ scheduler automatically deals with the varying load
situations and always distributes the bandwidth according to the weight factors.
Figure 3-23 Behavior of Different Scheduler Types
Data Sheet
as any of the attached queues has cells to send.
weights under any load condition.
rates fits into the available bandwidth.
Arrival Rate
Chapter 4.2.2.7
Priority
83
for a discussion on appropriate selection of
Multiplexer Rate
Round
Robin
Functional Description
WFQ
PXF 4336 V1.1
2001-12-17
ABM-P