pxf4333 Infineon Technologies Corporation, pxf4333 Datasheet - Page 88

• Manufacturer Part Number: pxf4333
• Description: Abm 3g Atm Buf Fer Manager
• Manufacturer: Infineon Technologies Corporation

3.4.3
The ABM-3G allows arbitrary assignment of connections to queues and of queues to
scheduler blocks. A scheduler block can be assigned to any UTOPIA PHY. Usage of a
scheduler differs in switch input (upstream) or output (downstream). For the Mini-Switch
application the upstream case does not exist.
At a switch output, the scheduler blocks provide constant cell streams to fill the payloads
of the PHYs. Either the entire cell stream of a PHY is provided or it is disassembled into
several VPCs as shown in
nections. This is the case for a VPC which connects two corporate networks (virtual
private networks), for example. The scheduler block concept has the advantage that
data traffic is automatically adjusted after setup or teardown of a real-time connection.
The output rate of a scheduler block in both applications is usually constant.
The scheduler blocks always react to UTOPIA backpressure or can be controlled com-
pletely by backpressure instead of shaping. All scheduler blocks whose physical outputs
are asserting backpressure hold on serving. Scheduler blocks serving time slots which
are lost due to temporary backpressure are maintained and served later, if possible.
Therefore, the rate with some CDV will be maintained. The maximum number of stored
time slots which can be configured is equal to the maximum burst possible for that port
or path.
Figure 3-32 Scheduler Block Usage at Switch Output
At a switch input, each scheduler block is assigned to a switch output
switch with n ports needs n
Data Sheet
Switch
Fabric
Scheduler Block Usage
Queue and Scheduler
ABM-3G for Port 1
Block Assignment
Figure
2
scheduler blocks. The output rate of each scheduler block
SB
SB
SB
3-32. A VPC may contain both real-time and data con-
88
VPC 1
VPC m
Virtual Paths, PHYs and Ports
PHY 1
PHY n
Functional Description
PXF 4333 V1.1
(Figure
Port 1
2001-12-17
ABM-3G
3-33). A