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Cisco 642-437 Exam
What is the decimal equivalent of the DSCP value AF21?
A. 16
B. 17
C. 18
D. 21
Correct Answer: C
Explanation/Reference:
Explanation: Assured Forwarding (AF) is a means to offer different levels of forwarding assurances for IPpackets. Four AF classes are defined, where each AF class is in each DS node allocated a certain amountof forwarding resources(buffer space and bandwidth). Within each AF class IP packets are marked withone of three possible drop precedence values. A congested node tries to protect packets with a lower dropprecedence 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 specifyingthe AF class with the probability. Bits DS5, DS4 and DS3 define the class; bits DS2 and DS1 specify thedrop probability; bit DS0 is always zero.
he following table illustrates the DSCP coding for specifying the AF class with the probability. Bits DS5, DS4and DS3 define the class; bits DS2 and DS1 specify the drop probability; bit DS0 is always zero.
Explanation/Reference:
Explanation: Assured Forwarding (AF) is a means to offer different levels of forwarding assurances for IPpackets. Four AF classes are defined, where each AF class is in each DS node allocated a certain amountof forwarding resources(buffer space and bandwidth). Within each AF class IP packets are marked withone of three possible drop precedence values. A congested node tries to protect packets with a lower dropprecedence 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 specifyingthe AF class with the probability. Bits DS5, DS4 and DS3 define the class; bits DS2 and DS1 specify thedrop probability; bit DS0 is always zero.
he following table illustrates the DSCP coding for specifying the AF class with the probability. Bits DS5, DS4and 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
