PXF4336 Datasheet, PDF (94/425 Pages) Infineon Technologies AG – ABM Premium ATM Buf fer Manager

ABM-P
PXF 4336 V1.1
Functional Description
is re-adjusted continuously to obtain maximum switch throughput without overloading
the switch port output rate. This principle is called Preemptive Congestion Control, that
is, congestion due to overload is avoided.
•
Ingress Port 1 (ABM-P)
SB
1
SB
n
Switch
Fabric
R1,1
Rn,1
Egress Port 1
Switch Fabric
Egress Port
Bottleneck
622 Mbps
SB
1
SB
n
Ingress Port n (ABM-P)
Switch Fabric
Ingress Port
Bottlenecks
R1,n
Switch Fabric
Egress Port
Rn,n
Bottleneck
622 Mbps
Egress Port n
Ri,j Rate through Switch from
Fabric Ingress Port i to
Fabric Egress Port j
Figure 3-33 Scheduler Block Usage at Switch Input
There are three options for scheduler block rate adjustment:
• After each connection setup or trade-in (static bandwidth allocation).
• Dynamic bandwidth allocation using input scheduler buffer fill information to assign
scheduler rates dynamically.
• Backpressure controlled.
3.4.4 Scheduler Block Scheduler (SBS)
The SBS performs a weighted round robin scheduling among the active SBs. As long as
the sum of the configured SB rates is below the service rate of the SBS, each SB
receives bandwidth up to the configured rate, depending on the load in the SB.
The SBS is said to be overbooked if the sum of the configured SB rates is above the
service rate of the SBS. In this case, the SBS behaves like an RR scheduler for the
overbooked SBs, which all receive an equal amount of bandwidth.
The SBS supports up to 128 Scheduler Blocks per direction. In addition to this, a
common real-time bypass queue (with fixed QID = 0) is supported.
Data Sheet
94
2001-12-17