cn8236 Mindspeed Technologies, cn8236 Datasheet - Page 98

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

4.0 Segmentation Coprocessor
4.3 Segmentation Control and Data Structures
Table 4-13. Segmentation Buffer Descriptor Field Descriptions (1 of 3)
4-20
UU
BASIZE_H
NEXT_PNTR
USER_PNTR
BUFFER_PNTR
LOCAL
SET_CI
SET_CLP
HEADER_MOD
RPL_VCI
OAM_STAT
GEN_PDU
CRC10
AAL_MODE
Field Name
AAL5 User-to-User indication. This field is copied to the VCC table entry UU field when BOM is set and
AAL_MODE is AAL5.
The high order bits used for the BASIZE field in the AAL3/4 header when the GEN_PDU option is
selected.
Pointer to next buffer descriptor for the VCC. The two least significant bits of the pointer are assumed
to be 0 (word-aligned). The host links segmentation buffer descriptors by writing this field to
[(ADDRESS of SDB)>>2] or [(ADDRESS of SBD)/4] before submitting the chain on the Transmit
Queue. The NEXT_PNTR of the last buffer descriptor in a chain is set to NULL (=0).
User data field returned in status entry. This field may equal BUFFER_PNTR. The SAR circulates this
field back to the host in the status entry without using it internally.
Pointer to segmentation buffer in host- or SAR-shared memory space. Host or SAR-shared memory
location is determined by the LOCAL bit.
0 = BUFFER_PNTR is a byte aligned PCI address.
1 = BUFFER_PNTR is a word-aligned address in SAR-shared memory instead of host memory.
0 = The CN8236 generates bit 1 of PTI[2:0] from the VCC table entry ATM_HEADER field.
1 = Sets bit 1 of the ATM header PTI[2:0] field for all cells in buffer to 1.
0 = The CN8236 generates the CLP bit from the VCC table entry ATM_HEADER field.
1 = Sets the ATM header CLP bit for all cells in buffer to 1.
Also used to control VBR CLP Dual Leaky Bucket mode.
0 = The CN8236 ignores the WR_GFC, WR_PTI, and WR_VCI bits in this buffer descriptor.
1 = Activates the WR_GFC, WR_PTI, and WR_VCI bits for this buffer descriptor.
0 = The CN8236 generates the VCI field from the VCC table entry ATM_HEADER field.
1 = The CN8236 generates the VCI field from the NEW_VCI for all cells in the buffer. NEW_VCI is also
Buffer reports status to the global OAM Status Queue SEG_CTRL(OAM_STAT_ID) instead of the STAT
specified in the VCC table entry.
For Message mode VCCs (VCC table entry STM_MODE = 0), the OAM_STAT bit of the last descriptor
for the CPCS-PDU determines which queue to use (even though the first descriptor is returned in
message mode).
See
1 = Generate AAL3/4 header and trailer, or AAL5 trailer. In AAL3/4 mode, the SAR-PDU is always gen-
Overwrite last ten bits of each cell with CRC10 calculation. Used for OAM and AAL3/4 cells.
Controls AAL segmentation mode.
00 = AAL5
01 = AAL0 Read 48-octet ATM cell payload from segmentation buffer. Only formatting is to set PTI[0]
10 = AAL3/4
11 = Reserved
erated internally.
copied in to the VCI portion of the ATM_HEADER field in the VCC entry.
Chapter
on last cell of an EOM buffer.
7.0—OAM for more details.
Mindspeed Technologies
ATM ServiceSAR Plus with xBR Traffic Management
Description
™
28236-DSH-001-B
CN8236