cn8237 Mindspeed Technologies, cn8237 Datasheet - Page 195

• Manufacturer Part Number: cn8237
• Description: Atm Oc-12 Servicesar Plus With Xbr Traffic Management
• Manufacturer: Mindspeed Technologies

CN8237
ATM OC-12 ServiceSAR Plus with xBR Traffic Management
Figure 6-22. ER Reduction Mapping
28237-DSH-001-C
15
HC_Shift
RS
VD
15 14 13
Explicit ER Modification
RSM VCC ENTRY
ER_HC_RATE Table Entry (16 bits)
NZ
12 11
ER_SHIFT Table Entry (16 bits)
Explicit CI and NI
HC_EXP (5)
Modification
HC_Index
9 8
ERS_INDEX
HC_MANT (9)
Added to word 10 of the RSM VCC table 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.
Added to word 10 of the RSM VCC table entry are EXP_TA_CI and
EXP_TA_NI.
cell is asserted. When EXP_TA_CI is a logic low, the value of CI in the
turned-around RM cell remains the same; that is, it reflects the EFCI field of the
last data cell ORed with the CI value from the FWD RM cell.
cell is 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
8237_077
6-39