RS8234 Mindspeed Technologies, RS8234 Datasheet - Page 119

• Manufacturer Part Number: RS8234
• Description: Atm Servicesar Plus With Xbr Traffic Management
• Manufacturer: Mindspeed Technologies

RS8234
ATM ServiceSAR Plus with xBR Traffic Management
5.3.3 AAL0 Processing
28234-DSH-001-B
Additional EOM/SSM
5.3.3.1 Termination
5.3.2.5 AAL3/4 MIB
5.3.2.4 AAL3/4
Processing
Counters
Methods
Upon termination of a CPCS-PDU, the RS8234 performs the following additional
checks and functions on each EOM or SSM cell received:
Whenever an AAL3/4 MIB counter rolls over to all zeros, the RS8234 writes a
RSM status queue entry with the CNT_ROVR bit set to a logic high, and the
HEAD_VCC_INDEX field pointing to the AAL3/4 Head VCC entry which
contains the rolled-over counter. This processing step takes place for the
CRC10_ERR, MID_ERR, LI_ERR, SN_ERR, BOM_SSM_ERR, and
EOM_ERR counters.
AAL0 is a transparent adaptation layer, allowing for pass-through of raw data
cells during CPCS-PDU processing. AAL0 channels are intended to be used for
AAL proprietary adaptation layers.
EOM and PTI termination.
for each VCC.
• The Length field in the CPCS-PDU trailer is written to the
• The RS8234 performs a Pad length check to see if the sum of all LIs for
• The RS8234 performs a Modulo 32 bit check. If the sum of all LIs for the
• If the Alignment (AL) field in the CPCS-PDU trailer is not all zeros, it sets
• If the BTAG field in the RSM VCC table entry does not match the ETAG
• The RS8234 checks the BAT_EN bit in the AAL3/4 Head VCC table entry.
• The RS8234 writes the AAL3/4 CPCS-PDU trailer to the data buffer.
The RS8234 provides two methods of terminating an AAL0 PDU: Cell Count
The TCOUNT field in the RSM VCC state table entry determines the method
• If TCOUNT = nonzero, Cell Count EOM PDU termination is enabled.
• If TCOUNT = zero, then PTI termination is enabled. In this case, a
CPCS_LENGTH field of a RSM status queue entry written for the VCC.
the CPCS-PDU - LENGTH - 8 = [0 to 3] octets. If in error, it sets the
PAD_ERROR bit in the status queue entry.
CPCS-PDU is not modulo 32 bit, the SAR sets the MOD_ERROR bit in
the status queue entry.
the AL_ERROR bit in the status queue entry.
field in the CPCS-PDU trailer, it sets the TAG_ERROR bit in the status
queue entry.
If BAT_EN is high, it compares the BASIZE field to the Length field in
the CPCS-PDU trailer. If not a match, it sets the BA_ERROR bit in the
status queue entry. If BAT_EN is low, it checks if the Length field is >
BASIZE; and if so, sets the BA_ERROR bit in the status queue entry.
PDUs will terminate when a fixed number of cells (TCOUNT) have been
received. CCOUNT must be initialized to a value of one in this mode.
received cell with PTI[0] set to one indicates the end of the AAL0
message. The total maximum allowable length of an AAL0 PDU in this
mode is (CCOUNT * 2) bytes.
Mindspeed Technologies
™
5.0 Reassembly Coprocessor
5.3 CPCS-PDU Processing
5-15