RS8234 Mindspeed Technologies, RS8234 Datasheet - Page 93

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

RS8234
ATM ServiceSAR Plus with xBR Traffic Management
28234-DSH-001-B
Table 4-6. Segmentation VCC Table Entry - AAL3/4, 5, and 0 Field Descriptions (1 of 2)
PM_INDEX
ACK_PM
FWD_PM
LAST_PNTR
UU
BOM_PNTR
ATM_HEADER
PDU_LEN
BUFFER_LEN
CRC_REM
BETAG
SN
MID
STM_MODE
STAT
PM_EN
LAST_CLP
Field Name
Performance Monitoring index. 128 VCCs may be selected for automatic OAM PM generation.
Each monitored VCC has a unique performance monitoring index.
If this field is changed while the VCC is active, only the byte containing the field should be written.
(See
Toggled after each backward reporting PM cell is sent. Used to prevent PM information in PM
table from being overwritten before cell is sent.
Indicates that next cell should be a forward monitoring PM cell.
Points to last buffer descriptor currently linked to the VCC. The two least significant bits of the
pointer are assumed to be zero (word-aligned). The address of the buffer descriptor is
(LAST_PNTR << 2) or (LAST_PNTR * 4).
AAL5 User-to-User indication. This field is copied from the buffer descriptor UU field. The RS8234
inserts the UU field in the CPCS-PDU trailer contained in the EOM cell.
In Message mode (STM_MODE=0), points to the first buffer descriptor of a message composed
of more than one buffer descriptor. The RS8234 returns the corresponding USER_PNTR from this
buffer descriptor in the status queue.
address of the buffer descriptor is (BOM_PNTR << 2) or (BOM_PNTR * 4).
Used for each ATM cell for the VCC. The transmitted header may be modified by option bits in the
current buffer descriptor.
CPCS-PDU Trailer Length field. This field is generated by the SAR and inserted in the Length field
of the EOM cell.
Buffer Length. The number of bytes of data read from the current segmentation buffer.
Accumulated value of AAL5 32-bit CRC, calculated on-the-fly by the SRC and appended to the
PDU at EOM.
AAL3/4 Btag and Etag fields.
AAL3/4 Sequence Number field.
AAL3/4 Message Id field.
Streaming Status Mode.
Identifies the Segmentation Status Queue used for all status entries.
Enables performance monitoring for the VCC. If this bit is changed while the VCC is active, only
the byte containing the bit should be written. (See
Last transmitted CLP bit for VCC. This bit is updated by the SRC after each transmitted cell. This
bit is in the same word as the PM_EN bit, and is copied by the SAR from the current buffer
descriptor. The bit is used to select the correct VBR bucket for certain VBR VCCs.
In Streaming mode (STM_MODE=1) it is not used.
The two least significant bits of the pointer are assumed to be zero (word-aligned). The
0 = Message Mode: a status entry is written (with a corresponding maskable interrupt) only
1 = Streaming Mode: a status entry is written (with a corresponding maskable interrupt) for
Chapter
when the last buffer in a message completes segmentation. The status entry written
corresponds to the first buffer descriptor in the message.
each buffer as it completes segmentation.
6.0).
Mindspeed Technologies
Description
Chapter
™
4.3 Segmentation Control and Data Structures
6.0.)
4.0 Segmentation Coprocessor
4-15