RS8234EBGC Mindspeed Technologies, RS8234EBGC Datasheet - Page 118

• Manufacturer Part Number: RS8234EBGC
• Description: RS8234EBGC ATM XBR SAR
• 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 RS8234 performs the following additional checks and functions on each
BOM or SSM cell received:
The RS8234 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 (i.e., with ST
• The RS8234 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 RS8234
• If the LI field in the SAR-PDU > (BASIZE+7), the SAR discards the cell,
• The RS8234 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 RS8234 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 zero value. If not a zero value, the
RS8234 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 zero. 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 RS8234 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 zero. 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 = zero.
greater than (BASIZE + 7). If so, the RS8234 discards the cell, terminates
the CPCS-PDU, and writes a status queue entry with the LEN_ERROR bit
set high, CPCS_LENGTH set to zero, 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
™
28234-DSH-001-B
RS8234