cn8237 Mindspeed Technologies, cn8237 Datasheet - Page 170

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

6.0 Traffic Management
6.2 xBR Cell Scheduler Functional Description
Figure 6-7. Assigning CBR Cell Slots
6-14
6.2.3.2 Available Rates
Assigning CBR Cell Slots
Minimum Rate
A
A
A
A
A
A
A
A
A
A
00
10
20
30
40
50
60
70
80
90
C
01
11
21
31
41
51
61
71
81
91
02
12
22
32
42
52
62
72
82
92
Once a maximum rate
determines the rate granularity and minimum rate. The system designer specifies
the number of table slots in SCH_SIZE(TBL_SIZE). The available CBR rates are
as follows:
The minimum rate available is therefore R
Figure 6-7
CBR channels, each with a different rate. In this example, TBL_SIZE = 100 and
SLOT_PER = 47. VCC_INDEX A occupies every tenth schedule slot; therefore,
it transmits at R/10, or 141.28 K cells/second. VCC_INDEX B occupies a slot
every 25 cell slots and transmits at a rate of R/25, or 56.512 K cells/second.
VCC_INDEX C occupies only one schedule slot and therefore transmits at the
minimum rate, R/TBL_SIZE, or 14.128 K cells/second. Not all cell slots have
been assigned to CBR channels. During these slots, the CN8237 dynamically
schedules traffic from the other service classes. However, the total bandwidth of
channels A, B, and C is reserved.
03
13
23
33
43
53
63
73
83
93
SCHEDULE TABLE
Mindspeed Technologies
B
B
R
displays an example of a Schedule table with slots assigned to various
04
14
24
34
44
54
64
74
84
94
max
, R
05
15
25
35
45
55
65
75
85
95
max
TBL_SIZE,... ..., R
x(TBL_SIZE –1) / TBL_SIZE, R
(R
06
16
26
36
46
56
66
76
86
96
ATM OC-12 ServiceSAR Plus with xBR Traffic Management
max
)
has been selected, the size of the Schedule table
07
17
27
37
47
57
67
77
87
97
08
18
28
38
48
58
68
78
88
98
max
B
B
™
09
19
29
39
49
59
69
79
89
99
max
/ TBL_SIZE
/ TBL_SIZE.
SCHEDULE SLOT
B
max
29
VCC_INDEX = B
x(TBL_SIZE – 2)/
28237-DSH-001-C
CN8237
8237_062