
PRELIMINARY
INVERSE MULTIPLEXING OVER ATM
PM7341 S/UNI-IMA-84
DATASHEET
PMC-2000223
ISSUE 4
INVERSE MULTIPLEXING OVER ATM
PROPRIETARY AND CONFIDENTIAL TO PMC-SIERRA, INC., AND FOR ITS CUSTOMERS’ INTERNAL USE
304
RDAT Link Context Memory (MEM_SELECT=4)
Purpose: Contains IMA state information for each IMA Physical Link. For IMA
connections, RDAT uses this memory to maintain the IFSM, IESM, OSM, and the
DCB write pointer for each Physical Link. Note that for all IMA links, the group
tag must be initialized prior to link addition, with all other fields initialized to zero.
For TC Links, this memory is used for the external write pointer and should be
initialized to zero.
Usage: IMA Groups and TC Links
Maintained by: RDAT.
Record Size: Two 32-bit words.
MEM_ADDR = (Physical Link Number x 2) + Word Offset
Table 25
RDAT Link Context Record
Word Bits
Parameter
Description
0
31
lcd_latch
Loss of Cell Delineation Defect latched status.
This status is maintained by the RDAT to report
occurrences of LCD on this link. This bit will be
set when an LCD defect is detected (as reported
in the HEC field), and will be cleared by the RDAT
when a valid ICP cell is received. The bit may
remain set if the LCD condition persists.
30
overrun_latch
DCB Overrun latched status. This status is
maintained by the RDAT to report occurrences of
DCB overrun. This bit will be set when a DCB
overrun is detected, and will be cleared by the
RDAT when a valid ICP cell is received. The bit
may remain set if the overrun condition persists.