RE: Calculating TOS Value

Yes - by definition - IP Precedence uses only the first three (leftmost) bits.

It is interesting to note that DSCP classifications were created to "mimic" this - these are the Class Selector (CS) PHBs and they ensure all 0s in those bit positions.

-----Original Message-----
From: nobody_at_groupstudy.com [mailto:nobody_at_groupstudy.com] On Behalf Of Edward John
Sent: Thursday, September 16, 2010 2:03 PM
To: Cisco certification
Subject: Calculating TOS Value

While calculating TOS value from a given precedence value, can we assume
that drop probability & reliability Bits as Zero?
ie
Precedence - 4 means
TOS = (100 *000* *00*)bin = 128

-- 
*Regards,*
*John*
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