# Convert PHB AF to DSCP Decimal and Vise Versa: It’s So Easy!

April 23, 2010 19 Comments

If you are searching any transformation formula from AF to DSCP decimal value and the vise versa then stop here! I have the solution for you! The rules are simple:

**From PHB AF to DSCP Decimal**

Decimal from **AFxy=(8*x)+(2*y)**

So, let’s have some example, let’s calculate decimal value from AF13, AF31 and AF43.

AF13 = (8*1)+(2*3) = DSCP 14

AF31 = (8*3)+(2*1) = DSCP 26

AF43 = (8*4)+(2*3) = DSCP 38

**From DSCP Decimal to PHB AF**

And the formula is tricky to calculate the vise versa, i mean, from DSCP value to PHB AF. The formula is:

*AFxy* where, *x = Floor Value [(DSCP Value)/8], y = [(Remainder)/2]*

So, let’s revert back those DSCP values to AF value.

DSCP 14 = AFxy where, x = Floor Value of (14/8) = 1, y = (Remainder)/2 = 6/2 = 3, so AFxy = AF13

DSCP 26 = AFxy where, x = Floor Value of (26/8) = 3, y = (Remainder)/2 = 2/2 = 1, so AFxy = AF31

DSCP 38 = AFxy where, x = Floor value of (38/8) = 4, y = (Remainder)/2 = 6/2 = 3, so AFxy = AF43

So you will never forget it, right? π

Nice formula

What about odd numbered DSCP values in the context of converting AF to DSCP

Great thanks. This is a very simple but powerful conversion you presented with extreme clearity.Kudos.

Hansen Kannie

hey what about DSCP46 ?

Thanks for this post- i used it @ https://www.facebook.com/groups/164049120368581/

if u have any objection i will remove it.

This is one of the most helpful tips ever. I was still using the “match dscp ?” under a bogus class-map, and the calculator. Not for the usal EF, or CSx, but to avoid being confused on the run. I can remember two simple formulas. REALLY Good. Thanks

This is great – thanks for sharing.

You made it easy…good on you mate, thanks

brilliant stuff … thanks

very nice and simple π thanks

Thanks!! Very usefull!

Very simple and great to remember, thanks a lot

Nice explanation. So easy to understand.

Thanks

Sriram

Thanks this has helped me a lot – preparing for the CCIE Written and was looking for a simple forumula and I found it here!

lovely Its great

My pleasure guys! π

Awesome summary, prepping to write Cvoice so it’s a great reference. Kudo’s sir.

Stephan

top way of doing it, needed a refresher. thanks again.

tnks soooo much π