pxf4336 Infineon Technologies Corporation, pxf4336 Datasheet - Page 105

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

3.5.1.4
ABR Mechanisms are classified depending on the way congestion information is
conveyed to the ABR source and the way switches make use of the information
contained in the RM cells passing through.
complexity increasing from top to bottom.
Table 3-43
ABR Mechanism
EFCI marking
Relative Rate Marking
Explicit Rate Marking
Reactive Switch
Control
VS/VD control
The implementation of the ABR mechanisms is mainly left to the manufacturer. It is
implicitly stated that the switch should update the RM cells in such a way that no cell
losses occur. The ABM-P supports all switch mechanisms mentioned above. The ABR
control loop with the different ABR mechanisms is shown below for one direction.
Figure 3-44 ABR Mechanisms
Data Sheet
Source and
sink RM cells
Source
ABR Mechanisms
adjust
ACR
ABR Mechanisms Supported in the ABM-P
BRM
EFCI marking
user cell flow
RM cell flow
Switch
ä ä ä ä
Description
“congestion experienced”
Setting CI and/or NI bits of forward or
backward RM cells to 1 (binary feedback)
Updating the ER field of forward or
backward RM cells
Explicit rate marking and additional
reduction of the forward transmission rate in
switches to the ER in received BRM cells
switch by building a virtual source (VS) and
virtual destination (VD)
Setting the PT bits in the user cell header to
Segmentation of the ABR control loop in a
set
PTI
FRM
update
Relative rate
or explicit rate
marking
Switch
BRM
ä ä ä ä ä ä ä ä
105
ä ä ä ä
Table 3-43
traffic measurement
Reactive switch control
update
Switch
BRM
ä ä ä ä
shows this classification with
adjust
ACR
BRM
Functional Description
BRM
FRM
Turn-around
RM cells
Destination
ABM
yes
yes
no
no
no
PXF 4336 V1.1
ä ä ä ä
update
2001-12-17
ABM-P
yes
yes
yes
yes
yes
ABM-P