Re: use of CS in qos?

Hey,

IPP uses the most significant 3 bits in the ToS field in the IP
header. With DSCP the CS values essentially do the same thing. In order to
be backwards compatible with IPP it only uses the 3 most significant bits.
Maybe this will help you visualize:

CSx Dec. IPP Binary

CS1 8 1 001 000
CS2 16 2 010 000
CS3 24 3 011 000
CS4 32 4 100 000
CS5 40 5 101 000
CS6 48 6 110 000
CS7 56 7 111 000

HTH

On Fri, Jul 3, 2009 at 5:04 PM, abderrahim sadki <a_sadki1_at_hotmail.com>wrote:

> Hi all.
>
> I understand that CS is used for backward compatibility with IP precedence.
>
> My question is :
> if a device only understands the IP precedence and it receives a packet
> with
> the dscp marking isnt it going to ignore the last 3 bits anyway?
>
> Thanks,
> Abderrahim
>
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