Calculating Random Early Detect Parameter Values
This appendix describes the means of calculating Random Early Detect (RED) min-th, max-th, and max-mark-spacing parameter values.
min-th to max-th Conversion
You can enter RED minimum threshold and maximum threshold values as a range, but IPriori translates the entered value into one of a set of discrete values associated with the parameter. If you do not enter one of the discrete values supported for the parameter, IPriori always rounds up to the nearest supported value. Minimum threshold can be configured for one of 15 fixed values. These values entered in kilo-bits are:
| min-th supported values in bits
|
16k = 16384 bits
|
32k = 32768 bits
|
65k = 65536 bits
|
131k = 131072 bits
|
262k = 262144 bits
|
524k = 524288 bits
|
1048k = 1048576 bits
|
2097k = 2097152 bits
|
4194k = 4194304 bits
|
8388k = 8388608 bits
|
16777k = 16777216 bits
|
33554k = 33554432 bits
|
67108k = 67108864 bits
|
134217k = 134217728 bits
|
268435k = 268435456 bits
|
For each fixed min-th value a set of 15 max-th can be calculated using the following formula:
(actual min-th value in kilobits) + (16384 * 2diff-th) where diff-th is an integer between 0 - 14.
The following example calculates the fourth differential (diff-th = 3) for a min-th of 16K:
16384 + (16384 * 23) = 147456
You configure max-th for 147k to get an actual value of 147456. Because the third differential value (diff-th = 2) is 81920, attempting to configure max-th for any value between 82k and 147k will provide and actual maximum threshold value of 147k (147456).
The following tables provide the actual max-th value given a min-th and diff-th:
Table A-1. max-th values from 16kb min-th
| diff-th
|
Actual min-th
|
Actual max-th
|
0
|
16 kb
|
32 kb
|
1
|
16 kb
|
49 kb
|
2
|
16 kb
|
81 kb
|
3
|
16 kb
|
147 kb
|
4
|
16 kb
|
278 kb
|
5
|
16 kb
|
540 kb
|
6
|
16 kb
|
1064 kb
|
7
|
16 kb
|
2113 kb
|
8
|
16 kb
|
4210 kb
|
9
|
16 kb
|
8404 kb
|
10
|
16 kb
|
16793 kb
|
11
|
16 kb
|
33570 kb
|
12
|
16 kb
|
67125 kb
|
13
|
16 kb
|
134234 kb
|
14
|
16 kb
|
268451 kb
|
Table A-2. max-th values from 32kb min-th
| diff-th
|
Actual min-th
|
Actual max-th
|
0
|
32 kb
|
49
|
1
|
32 kb
|
65 kb
|
2
|
32 kb
|
98 kb
|
3
|
32 kb
|
163 kb
|
4
|
32 kb
|
294 kb
|
5
|
32 kb
|
557 kb
|
6
|
32 kb
|
1081 kb
|
7
|
32 kb
|
2129 kb
|
8
|
32 kb
|
4227 kb
|
9
|
32 kb
|
8421 kb
|
10
|
32 kb
|
16809 kb
|
11
|
32 kb
|
33587 kb
|
12
|
32 kb
|
67141 kb
|
13
|
32 kb
|
134250 kb
|
14
|
32 kb
|
268468
|
Table A-3. max-th values from 65kb min-th
| diff-th
|
Actual min-th
|
Actual max-th
|
0
|
65 kb
|
81
|
1
|
65 kb
|
98 kb
|
2
|
65 kb
|
131 kb
|
3
|
65 kb
|
196 kb
|
4
|
65 kb
|
327 kb
|
5
|
65 kb
|
589 kb
|
6
|
65 kb
|
1114 kb
|
7
|
65 kb
|
2162 kb
|
8
|
65 kb
|
4259 kb
|
9
|
65 kb
|
8454 kb
|
10
|
65 kb
|
16842 kb
|
11
|
65 kb
|
33619 kb
|
12
|
65 kb
|
67174 kb
|
13
|
65 kb
|
134283 kb
|
14
|
65 kb
|
268500 kb
|
Table A-4. max-th values from 131kb min-th
| diff-th
|
Actual min-th
|
Actual max-th
|
0
|
131 kb
|
147 kb
|
1
|
131 kb
|
163 kb
|
2
|
131 kb
|
196 kb
|
3
|
131 kb
|
262 kb
|
4
|
131 kb
|
393 kb
|
5
|
131 kb
|
655 kb
|
6
|
131 kb
|
1179 kb
|
7
|
131 kb
|
2228 kb
|
8
|
131 kb
|
4325 kb
|
9
|
131 kb
|
8519 kb
|
10
|
131 kb
|
16908 kb
|
11
|
131 kb
|
33685 kb
|
12
|
131 kb
|
67239 kb
|
13
|
131 kb
|
134348 kb
|
14
|
131 kb
|
268566 kb
|
Table A-5. max-th values from 262kb min-th
| diff-th
|
Actual min-th
|
Actual max-th
|
0
|
262 kb
|
278 kb
|
1
|
262 kb
|
294 kb
|
2
|
262 kb
|
327 kb
|
3
|
262 kb
|
393 kb
|
4
|
262 kb
|
524 kb
|
5
|
262 kb
|
786 kb
|
6
|
262 kb
|
1310 kb
|
7
|
262 kb
|
2359 kb
|
8
|
262 kb
|
4456 kb
|
9
|
262 kb
|
8650 kb
|
10
|
262 kb
|
17039 kb
|
11
|
262 kb
|
33816 kb
|
12
|
262 kb
|
67371 kb
|
13
|
262 kb
|
134479 kb
|
14
|
262 kb
|
268697 kb
|
Table A-6. max-th values from 524kb min-th
| diff-th
|
Actual min-th
|
Actual max-th
|
0
|
524 kb
|
540
|
1
|
524 kb
|
557 kb
|
2
|
524 kb
|
589 kb
|
3
|
524 kb
|
655 kb
|
4
|
524 kb
|
786 kb
|
5
|
524 kb
|
1048 kb
|
6
|
524 kb
|
1572 kb
|
7
|
524 kb
|
2621 kb
|
8
|
524 kb
|
4718 kb
|
9
|
524 kb
|
8912 kb
|
10
|
524 kb
|
17301 kb
|
11
|
524 kb
|
34078 kb
|
12
|
524 kb
|
67633 kb
|
13
|
524 kb
|
134742 kb
|
14
|
524 kb
|
268959 kb
|
Table A-7. max-th values from 1048kb min-th
| diff-th
|
Actual min-th
|
Actual max-th
|
0
|
1048 kb
|
1064 kb
|
1
|
1048 kb
|
557 kb
|
2
|
1048 kb
|
589 kb
|
3
|
1048 kb
|
655 kb
|
4
|
1048 kb
|
786 kb
|
5
|
1048 kb
|
1048 kb
|
6
|
1048 kb
|
1572 kb
|
7
|
1048 kb
|
2621 kb
|
8
|
1048 kb
|
4718 kb
|
9
|
1048 kb
|
8912 kb
|
10
|
1048 kb
|
17301 kb
|
11
|
1048 kb
|
34078 kb
|
12
|
1048 kb
|
67633 kb
|
13
|
1048 kb
|
134742 kb
|
14
|
1048 kb
|
269484 kb
|
Table A-8. max-th values from 2097kb min-th
| diff-th
|
Actual min-th
|
Actual max-th
|
0
|
2097 kb
|
2113 kb
|
1
|
2097 kb
|
2129 kb
|
2
|
2097 kb
|
2162 kb
|
3
|
2097 kb
|
2228 kb
|
4
|
2097 kb
|
2359 kb
|
5
|
2097 kb
|
2621 kb
|
6
|
2097 kb
|
3145 kb
|
7
|
2097 kb
|
4194 kb
|
8
|
2097 kb
|
6291 kb
|
9
|
2097 kb
|
10485 kb
|
10
|
2097 kb
|
18874 kb
|
11
|
2097 kb
|
35651 kb
|
12
|
2097 kb
|
69206 kb
|
13
|
2097 kb
|
136314 kb
|
14
|
2097 kb
|
270532 kb
|
Table A-9. max-th values from 4194kb min-th
| diff-th
|
Actual min-th
|
Actual max-th
|
0
|
4194 kb
|
4210 kb
|
1
|
4194 kb
|
4227 kb
|
2
|
4194 kb
|
4259 kb
|
3
|
4194 kb
|
4325 kb
|
4
|
4194 kb
|
4456 kb
|
5
|
4194 kb
|
4718 kb
|
6
|
4194 kb
|
5242 kb
|
7
|
4194 kb
|
6291 kb
|
8
|
4194 kb
|
8388 kb
|
9
|
4194 kb
|
12582 kb
|
10
|
4194 kb
|
20971 kb
|
11
|
4194 kb
|
37748 kb
|
12
|
4194 kb
|
71303 kb
|
13
|
4194 kb
|
138412 kb
|
14
|
4194 kb
|
272629 kb
|
Table A-10. max-th values from 8388kb min-th
| diff-th
|
Actual min-th
|
Actual max-th
|
0
|
8338 kb
|
8404 kb
|
1
|
8338 kb
|
8421 kb
|
2
|
8338 kb
|
8454 kb
|
3
|
8338 kb
|
8519 kb
|
4
|
8338 kb
|
8650 kb
|
5
|
8338 kb
|
8912 kb
|
6
|
8338 kb
|
9437 kb
|
7
|
8338 kb
|
10485 kb
|
8
|
8338 kb
|
12582 kb
|
9
|
8338 kb
|
16777 kb
|
10
|
8338 kb
|
25165 kb
|
11
|
8338 kb
|
41943 kb
|
12
|
8338 kb
|
75497 kb
|
13
|
8338 kb
|
142606 kb
|
14
|
8338 kb
|
276824 kb
|
Table A-11. max-th values from 16777kb min-th
| diff-th
|
Actual min-th
|
Actual max-th
|
0
|
16777 kb
|
16793 kb
|
1
|
16777 kb
|
16809 kb
|
2
|
16777 kb
|
16842 kb
|
3
|
16777 kb
|
16908 kb
|
4
|
16777 kb
|
17039 kb
|
5
|
16777 kb
|
17301 kb
|
6
|
16777 kb
|
17825 kb
|
7
|
16777 kb
|
18874 kb
|
8
|
16777 kb
|
20971 kb
|
9
|
16777 kb
|
25165 kb
|
10
|
16777 kb
|
33554 kb
|
11
|
16777 kb
|
50331 kb
|
12
|
16777 kb
|
83886 kb
|
13
|
16777 kb
|
150994 kb
|
14
|
16777 kb
|
285212 kb
|
Table A-12. max-th values from 33554kb min-th
| diff-th
|
Actual min-th
|
Actual max-th
|
0
|
33554 kb
|
33570 kb
|
1
|
33554 kb
|
33587 kb
|
2
|
33554 kb
|
33619 kb
|
3
|
33554 kb
|
33685 kb
|
4
|
33554 kb
|
33816 kb
|
5
|
33554 kb
|
34078 kb
|
6
|
33554 kb
|
34603 kb
|
7
|
33554 kb
|
35651 kb
|
8
|
33554 kb
|
37748 kb
|
9
|
33554 kb
|
41943 kb
|
10
|
33554 kb
|
50331 kb
|
11
|
33554 kb
|
67108 kb
|
12
|
33554 kb
|
100663 kb
|
13
|
33554 kb
|
167772 kb
|
14
|
33554 kb
|
301989 kb
|
Table A-13. max-th values from 67108kb min-th
| diff-th
|
Actual min-th
|
Actual max-th
|
0
|
67108 kb
|
67125 kb
|
1
|
67108 kb
|
67141 kb
|
2
|
67108 kb
|
67174 kb
|
3
|
67108 kb
|
67239 kb
|
4
|
67108 kb
|
67371 kb
|
5
|
67108 kb
|
67633 kb
|
6
|
67108 kb
|
68157 kb
|
7
|
67108 kb
|
69206 kb
|
8
|
67108 kb
|
71303 kb
|
9
|
67108 kb
|
75497 kb
|
10
|
67108 kb
|
83886 kb
|
11
|
67108 kb
|
100663 kb
|
12
|
67108 kb
|
134217 kb
|
13
|
67108 kb
|
201326 kb
|
14
|
67108 kb
|
335544 kb
|
Table A-14. max-th values from 134217kb min-th
| diff-th
|
Actual min-th
|
Actual max-th
|
0
|
134217 kb
|
134234 kb
|
1
|
134217 kb
|
134250 kb
|
2
|
134217 kb
|
134283 kb
|
3
|
134217 kb
|
134348 kb
|
4
|
134217 kb
|
134479 kb
|
5
|
134217 kb
|
134742 kb
|
6
|
134217 kb
|
135266 kb
|
7
|
134217 kb
|
136314 kb
|
8
|
134217 kb
|
138412 kb
|
9
|
134217 kb
|
142606 kb
|
10
|
134217 kb
|
150994 kb
|
11
|
134217 kb
|
167772 kb
|
12
|
134217 kb
|
201326 kb
|
13
|
134217 kb
|
268435 kb
|
14
|
134217 kb
|
402653 kb
|
Table A-15. max-th values from 268435kb min-th
| diff-th
|
Actual min-th
|
Actual max-th
|
0
|
268435 kb
|
268451 kb
|
1
|
268435 kb
|
268468 kb
|
2
|
268435 kb
|
268500 kb
|
3
|
268435 kb
|
268566 kb
|
4
|
268435 kb
|
268697 kb
|
5
|
268435 kb
|
268959 kb
|
6
|
268435 kb
|
269484 kb
|
7
|
268435 kb
|
270532 kb
|
8
|
268435 kb
|
272629 kb
|
9
|
268435 kb
|
276824 kb
|
10
|
268435 kb
|
285212 kb
|
11
|
268435 kb
|
301989 kb
|
12
|
268435 kb
|
335544 kb
|
13
|
268435 kb
|
402653 kb
|
14
|
268435 kb
|
536870 kb
|
