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Sunday, June 10, 2012

yet more dscp...

cribbed from ine, by scott morris http://ieoc.com/forums/p/5257/17674.aspx


AF11 is not a hex value...  So the calculator won't help you much.  :)

It means Class 1 Threshold 1.

Now, the class value = IP Prec value where is where we start with the backwards compatibility.

IP Prec 0 = DSCP 0 (000 vs 000000)
IP Prec 1 = DSCP 8 (001 vs 001000)
IP Prec 2 = DSCP 16 (010 vs 010000)
IP Prec 3 = DSCP 24 (011 vs 011000)
IP Prec 4 = DSCP 32 (100 vs 100000)
IP Prec 5 = DSCP 40 (101 vs 101000)
IP Prec 6 = DSCP 48 (110 vs 110000)
IP Prec 7 = DSCP 56 (111 vs 111000)

Now, the thresholds use the "2-bit" and "4-bit" positions for values (00 being the default class)

01 = Threshold 1 (therefore 001010 is AF 11 or DSCP 10)
10 = Threshold 2 (therefore 001100 is AF 12 or DSCP 12 (the ONLY overlap in numbers))
11 = Threshold 3 (therefore 001110 is AF 13 or DSCP 14)

Just change the first three bits for the remainder of the classes 1 through 4.

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