pxf4336 Infineon Technologies Corporation, pxf4336 Datasheet - Page 91

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

3.4.2.5
Any queue can be configured (mutually exclusive) to participate in a VC-merge group or
as a ‘dummy queue’. A detailed description of enabling/disabling those special queue
functions is provided in the description of
Registers QCT0..6” on Page
3.4.2.5.1 VC-Merge
Several logical queues carrying AAL5 packets may be grouped together into one of a
maximum of 128 merge groups. Functionally, a Packet Round-Robin (PRR) scheduler
stage is inserted between the queues of the merge group and the first scheduling stage
of the scheduler block. Whenever a complete packet is queued in a QID of a merge
group, this QID is enabled to the PRR. The PRR schedules a QID to the SB until all cells
of the current packet are transmitted. Then it switches to the next enabled QID.
Hence, viewed from the Scheduler Block, a merge group appears like a single queue
with the additional benefit that the output VC maintains AAL5 packet boundaries. See
Figure
Figure 3-31 VC Merge Scheduling
Any queue can be configured to be member of one of the 128 merge groups in the QCT
by setting ’RSall’ = 0 in
DQsch’ = 1 and ’MGID’ to the desired merge group identifier in
Page
If the queue is the first queue of the merge group, then its QID must be written into field
’Head_Pointer’ in
Assigning a queue to a VC-merge group already enables the packet boundary aware
scheduling of all queues within the same group.
Data Sheet
VCx
VCy
VCz
x x x
x x x
x x x
ATM cell
optional shaper
264.
3-31.
Packet b
VC-Merge and Dummy Queue
Packet c
Packet a
Register 57 "MGT2" on Page
Register 44 "QCT1" on Page 261
Merge
QIDx
QIDy
QIDz
Group
258.
Packet-RR
Active QIDx
x x x
x x x
x x x
SB
91
“Queue Configuration Table Transfer
281.
Packet b
Output with VC merge function
Packets destroyed
Output without VC merge function
Packet c
and then setting ’MGconf/
Functional Description
Register 45 "QCT2" on
PXF 4336 V1.1
Packet a
2001-12-17
ABM-P
VC