A DSCP value of 41 in decimal corresponds to which IP precedence value?
A.
3 – Flash
B.
4 – Flash Override
C.
5 – Critical
D.
6 – Internet Control
E.
7 – Network Control
Explanation:
= INT(41/8)
The AF behavior group defines four separate AF classes with Class 4 having the highest priority.
Within each class, packets are given a drop precedence (high, medium or low). The combination
of classes and drop precedence yields twelve separate DSCP encodings from AF11 through AF43 (see table)
Network Layer, IP header ToS Byte
7 6 5 4 3 2 1 0 – position of bits
P P P 0 0 0 0 0 – IP Precedence – 3 most significant bits
D D D D D D E E – DiffServ – 6 most significant bits; E = ECN
32 16 8 4 2 1 x x = DSCP bit value
1 0 1 0 0 1 0 0 = DSCP (41)
4 2 1 0 0 0 0 0 = IP Precedence bit value
1 0 1 0 0 0 0 0 = IP Precedence (5)
Data Link Layer CoS bits:
CoS 7 (111): network
CoS 6 (110): Internet
CoS 5 (101): critical
CoS 4 (100): flash override
CoS 3 (011): flash
CoS 2 (010): immediate
CoS 1 (001): priority
CoS 0 (000): routine
Map data link-to-network layer markings to offer a complete end-to-end QoS solution that does not depend on any specific link-layer technology.
CoS 5 (101) = IP Precedence 5 (101) = critical
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