cn8236 Mindspeed Technologies, cn8236 Datasheet - Page 124

• Manufacturer Part Number: cn8236
• Description: Atm Servicesar Plus With Xbr Traffic Management
• Manufacturer: Mindspeed Technologies

5.0 Reassembly Coprocessor
5.3 CPCS-PDU Processing
5-14
Additional BOM/SSM
5.3.2.2 AAL3/4
5.3.2.3 AAL3/4
Additional COM
Processing
Processing
The CN8236 performs the following additional checks and functions on each
BOM or SSM cell received:
The CN8236 performs the following additional checks and functions on each
COM cell received:
• If the SN_EN bit in the AAL3/4 Head VCC table entry is a logic high, the
• When a BOM cell is received for an AAL3/4 CPCS-PDU (that is, with ST
• The CN8236 also checks if the BAH_EN bit in the RSM AAL3/4 Head
• If the CPI and BASIZE fields are correct in the BOM cell, the CN8236
• If the LI field in the SAR-PDU > (BASIZE+7), the SAR discards the cell,
• The CN8236 checks if the sum of the LI fields for the CPCS-PDU are
– If the cell received is an EOM, and the SAR was expecting a BOM or
SN field in the cell is checked. If the cell received is an COM or EOM, and
the SN field does not equal the NEXT_SN field in the VCC table entry, the
SAR discards the cell, terminates the current CPCS-PDU, and writes a
status queue entry with the SN_ERROR bit set, CPCS_LENGTH = 0, and
the BD_PNTR pointing to the partially reassembled PDU. The SAR also
increments the SN_ERR counter in the VCC Head table entry.
field set to b10), the CN8236 checks if the CPI_EN bit in the RSM
AAL3/4 Head VCC table entry is set to a logic high. If so, the CPI field in
the received cell is checked for a 0 value. If not a 0 value, the CN8236
treats this as an error condition and discards the cell, terminates the current
CPCS-PDU, writes a status queue entry with the CPI_ERROR bit set, and
the CPCS_LENGTH and BD_PNTR fields set to 0. Cells up to and
including the next EOM are discarded.
entry is set to a logic high. If so, it checks if the BASIZE field in the
CPCS-PDU header is less than 37 octets, and if so, the CN8236 discards
the current cell, terminates the current CPCS-PDU, and writes a status
queue entry with the BA_ERROR bit set, and the CPCS_LENGTH and
BD_PNTR fields set to 0. Cells up to and including the next EOM are
discarded.
copies the BASIZE and BTAG fields into the VCC table entry for that
MID, and sets the NEXT_ST and NEXT_SN values in the VCC table
entry. It also writes the CPCS-PDU header into the data buffer.
terminates the CPCS-PDU, and writes a status queue entry with the
LEN_ERROR bit set and CPCS_LENGTH = 0.
greater than (BASIZE + 7). If so, the CN8236 discards the cell, terminates
the CPCS-PDU, and writes a status queue entry with the LEN_ERROR bit
set high, CPCS_LENGTH set to 0, and BD_PNTR pointing to the partially
reassembled PDU.
Mindspeed Technologies
SSM, the SAR discards the cell, and increments the EOM_ERR
counter in the VCC Head table entry.
ATM ServiceSAR Plus with xBR Traffic Management
™
28236-DSH-001-B
CN8236