Cisco Exam Questions

What is the decimal equivalent of the DSCP value AF21?

What is the decimal equivalent of the DSCP value AF21?

A.
16

B.
17

C.
18

D.
21

Explanation:
Assured Forwarding (AF) is a means to offer different levels of forwarding
assurances for IP packets. Four AF classes are defined, where each AF class is in each DS node
allocated a certain amount of forwarding resources(buffer space and bandwidth). Within each AF
class IP packets are marked with one of three possible drop precedence values. A congested
node tries to protect packets with a lower drop precedence value from being lost by preferably
discarding packets with a higher drop precedence value. Classes 1 to 4 are referred to as AF
classes. The following table illustrates the DSCP coding for specifying the AF class with the
probability. Bits DS5, DS4 and DS3 define the class; bits DS2 and DS1 specify the drop
probability; bit DS0 is always zero.
he following table illustrates the DSCP coding for specifying the AF class with the probability. Bits
DS5, DS4 and DS3 define the class; bits DS2 and DS1 specify the drop probability; bit DS0 is
always zero.

http://www.cisco.com/en/US/tech/tk543/tk757/technologies_tech_note09186a00800949f2.shtml