![](http://datasheet.mmic.net.cn/330000/PM7329-BI_datasheet_16444382/PM7329-BI_99.png)
PM7329 S/UNI-APEX-1K800
DATASHEET
PMC-2010141
ISSUE 2
ATM TRAFFIC MANAGER AND SWITCH
PROPRIETARY AND CONFIDENTIAL TO PMC-SIERRA, INC., AND FOR ITS CUSTOMERS’ INTERNAL USE
85
Discard Mode
cell
EPD/PPD
FCQ
VcGFRMode
x
x
x
0
1
x
x
0
1
Condition
Cell Type
x
pass
thru
OAM
redir
ect
OAM
user user pass
thru
OAM
redir
ect
OAM
user user
CLP0DiscardCnt
or
CLP1DiscardCnt
cell
cell
cell
cell
BOM cell
cell
OR
BOM
One reads the table vertically. Take the last column. A user cell arrives in a
connection configured for FCQ, VcGFRMode = 1, will have
-its discard decision made on a cell by cell basis;
-the CLP is defined by the BOM for discard purposes;
-the minimum CLP0 count will be incremented based on the BOM, if the frame is
not discarded;
-either VcCLP0TxCnt or VcCLP1TxCnt will be incremented based on the CLP of
the cell, if the frame is not discarded;
--either CLP0DiscardCnt or CLP1DiscardCnt will be incremented based on the
CLP of the BOM, if the frame is discarded.
10.9.6 Microprocessor Queue Buffer Re-allocation/Tear Down
The microprocessor has the option of engaging one of two macros that provide a
fast mechanism to tear down either a VC queue or a Class queue for non-
shaped port class. Specified and initiated through registers, the macro will go to
the specified queue, reclaim the buffers in the queue, and reset the appropriate
congestion counters. The number of cells that were in the queue are added to
the general discard count. The VC queue or Class queue remain enabled after
the re-allocation. Invoking of these functions may reduce general throughput of
the device.
10.10 Context Memory SSRAM Interface
The context memory SSRAM interface stores and retrieves context data from
one of two SSRAM devices: pipelined ZBT or register-to-register late write. Up to
4 banks and 4 SSRAM devices are supported, with 1M addressing capability for
a total of 4MB data capacity. 2 parity bits are provided to protect the 34-bit data
bus. If a parity error occurs, an interrupt is sent to the microprocessor.