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5.0 Reassembly Coprocessor
5.7 Reassembly Control and Status Structures
RS8234
Datasheet for RS8234 xBR ServiceSAR
N8234DS1B
Table 5-15. Reassembly VCC Table Descriptions (1 of 2)
Field Name
Description/Function
VC_EN
Enables the VCC Table entry. If disabled, the cell is discarded.
AAL_TYPE
When VC_EN is a logic high, configure channel to process specific AA; otherwise, when VC_EN is
a logic low, a value of “11” will cause the CELL_DSC_CNT counter not to be incremented.
00 - AAL5
01 - AAL0
10 - AAL3/4
11 - Reserved
DPRI
Discard Priority value. Compared against global priority in CLP and Frame Relay discard modes to
determine discard eligibility. In LANE-LECID echo suppression mode, this field is the index into the
LECID table that holds channel LECID values.
FF_DSC
FIFO Full Discard. When a logic high, cells will be discarded when the incoming DMA FIFO is
almost full. This includes OAM cells when RSM_CTRL1(OAM_QU_EN) is a logic low.
TO_INDEX
Selects one of eight INIT_TOCNT values in internal SRAM.
PM_INDEX
Pointer to a PM OAM processing word. Index with reference to top of VPI Index table.
AAL_EN
Enable various cell processes. The AAL_EN field contains the following control bits:
PM_EN - - - - - Enable PM OAM processing on this channel.
FIFO_EN - - - - - Enable Logical FIFO Mode.
LNK_EN - - - - - Enable writing of buffer descriptor NEXT field.
FW_EN - - - - - Enable firewall processing. Used in conjunction with FWALL_EN bit in RSM_CTR0.
M52_EN - - - - - If set high, all 52 octets of the cell are written to a cell buffer.
BINTR - - - - - Enable interrupt after BOM buffer filled in Message Mode.
STM_MODE - - - - - Enable Streaming Mode.
LECID_EN - - - - - Enable LANE-LECID echo suppression. Invalid in AAL3/4.
FRD_EN - - - - - Enable frame relay DE (Discard Eligibility) Mode. Invalid in AAL3/4.
CLPD_EN - - - - - Enable CLP Discard Mode. Invalid in AAL3/4.
PDU_FLAGS
Set various flags related to PDUs. The PDU_FLAGS field contains the following control bits:
CNT_ROVR - - - - - Indication that SERVICE_CNT counters have rolled over. The next status entry
will indicate this condition.
SFPD_PND - - - - - Status Full Packet Discard Pending. Set when status queue is full, and CPCS
needs to be discarded when status entries available.
EPD - - - - - Early Packet Discard Flag. Set when EPD occurs on a channel. Cleared when new
packet starts and error condition cleared.
CI - - - - - Congestion Indication. PTI[1] header bit ORed across the CPCS-PDU.
CLP - - - - - Cell Loss Priority. CLP header bit ORed across the CPCS-PDU.
BFR_LOCAL - - - - - Buffer Local. If high, the current cell buffer is located in local memory; other-
wise, host memory. SAR maintains this bit.
BD_LOCAL - - - - - Buffer Descriptor Local. If high, the buffer descriptors reside in local memory;
otherwise, host memory. SAR maintains this bit.
ACT_PDU - - - - - Active PDU. Indication that at least one buffer has been taken off of the free
buffer queue for the current PDU being received.
BOM_BUF - - - - - BOM buffer flag. Set high when filling the first buffer of a PDU.
FFPD_PND - - - - - DMA FIFO Full Packet Discard Pending.
PM_EN
FIFO_EN
LNK_EN
FW_EN
M52_EN
BINTR
STM_MODE LECID_EN FRD_EN CLPD_EN
CNT_ROVR SFPD_PND EPD
CI
CLP
BFR_LOCALBD_LOCAL
BOM_BUF
ACT_PDU
FFPD_PND