cn8236 Mindspeed Technologies, cn8236 Datasheet - Page 207

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

CN8236
ATM ServiceSAR Plus with xBR Traffic Management
Figure 6-22. ER Reduction Mapping
28236-DSH-001-B
15
HC_Shift
RS
VD
15 14 13
RSM VCC ENTRY
ER_HC_RATE Table Entry (16 bits)
NZ
12 11
ER_SHIFT Table Entry (16 bits)
HC_EXP (5)
HC_Index
9 8
ERS_INDEX
HC_MANT (9)
Explicit ER Modification
Added to word 10 of the RSM VCC table entry and AAL3/4 head VCC entry are
EN_EXP_CNG and EXP_TA_ER.
ABR block compares the ER value in the RM cell with EXP_TA_ER and writes
the lower value to TA_ER field of the SEG VCC table entry.
Explicit CI and NI Modification
Added to word 10 of the RSM VCC table entry and AAL3/4 head VCC table
entry are EXP_TA_CI and EXP_TA_NI.
cell are asserted. When EXP_TA_CI is a logic low the value of CI in the
turnaround RM cell is as it has been; that is, it reflects the EFCI field of the last
data cell OR’d with the CI value from the FWD RM cell.
cell are logic high; otherwise, the FWD RM cell value of NI is reflected in the
turned around BCK RM cell.
ER_SHIFT_B
When EX_EXP_CNG is a logic high and a forward RM cell is received, the
When EXP_TA_CI is a logic high, the value of CI in the turned-around RM
When EXP_TA_NI is a logic high, the value of NI in the turned around RM
HC_Index
Mindspeed Technologies
0
0
Rate Entry n-2
Rate Entry 1
Rate Entry n
Entry 29
Entry 31
Entry 29
Entry 31
Entry 1
Entry 1
Mantissa Shift
™
Rate Entry n-3
Rate Entry n-1
Rate Entry 0
Entry 28
Entry 30
Entry 28
Entry 30
Entry 0
Entry 0
6.3 ABR Flow Control Manager
6.0 Traffic Management
ER_SHIFT
Table 0
ER_SHIFT
Table 63
ER_HC_RATE
Table
8236_053
6-39