pxf4336 Infineon Technologies Corporation, pxf4336 Datasheet - Page 149

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

4.2.5
Due to the WFQ Scheduler concept of the ABM-P, the Connection Acceptance Check
(CAC) is very simple:
• Check if the Guaranteed Rate of the connection fits within the spare bandwidth of the
For the definition of the Guaranteed Rate, see
be reduced to the following formulas:
For all connections make sure that no overbooking of the configured scheduler output
rate CCR
For real-time connections, (CBR, rt-VBR)
For non-real-time connections or connections using the WFQ scheduler, additional con-
ditions must be fulfilled.
VBR, ABR and UBR+ connections must be setup in per VC queueing configurations, that
is, an empty queue must be found for the connection. The Guaranteed Rate determines
the weight of the queue.
4.2.5.1
As an example, an access network multiplexer is assumed with ADSL lines and an E3
uplink. CBR and UBR+ connections are supported. A minimum Guaranteed Rate of
GR
ularity for higher values.
This behavior is well suited to the Guaranteed Rates which are minimum or sustainable
rates. The values for MCR and SCR will be well below 10 Mbit/s for public networks. In
high speed LANs with high MCR and SCR values, a higher minimum rate could be
selected.
Additionally, it is assumed that three types of line interfaces (PHY) exist in the system:
34 Mbit/s for the uplink, ADSL rates of 8 Mbit/s downstream, and 0.6 Mbit/s upstream.
For each PHY, a maximum possible weight factor 1/n exists: n
= 524, respectively.
Two types of non-real-time connection are defined with Guaranteed Rates of 100 kbit/s
and 20 Kbps with the weight factors 1/n, n
100 Kbps connections would be used for the downstream direction, and the 20 Kbps
connections for the upstream direction.
nections possible on each PHY.
Data Sheet
Scheduler.
min
= 19.2 Kbps is selected. This allows GR up to 314.57 Mbit/s with increasing gran-
out
Bandwidth Reservation
Bandwidth Reservation Example
occurs, i.e.:
å
i
GCR
i
=
CCR
out
Table 4-8
Equation (30)
100
149
= 3146 and n
Table
provides the maximum number of con-
3-24. Mathematically, the CAC can
is the only condition required.
20
= 15730, respectively. The
max
Operational Description
= 9, n
PXF 4336 V1.1
max
= 39, and n
2001-12-17
ABM-P
(30)
max