Note

DiffServ classes of service are not be confused with Layer 2 classes of service for Inter-Switch (ISL), or 802.1Q frame-marking services on local-area networks. This chapter only uses the te class of service to refer to Layer 3 packet marking.

Table 5-10. Type of Service Values

Hexadecimal Bits

Decimal Value

Type of Service

Cisco IOS Software ToS Valu

0000

0

Normal

no rmal

1000

8

Minimize delay

min-dela y

0100

4

Maximize throughput

max-t1roug1put

00 10

2

Maximize re liability

max-reliability

0001

1

Minimi ze cost

min-monetary-cost

Using the ToS values, it is possible to mark packets from certain applications and use that classifica information l ater in the network when congest ion is encountered to provide these applications with levels of serv ice. By defau I t, all I P packets have a ToS value nf 0000, spetifying th at ehey should be with a normal " beat-effort" s ervice leve L With Ciscn IOS Software. it is possible to ch ange the ToS define appl i cation traffic us 1 ng hccess lists, as shown in Examp1 e 5-20. Using eccess H sts, you can c ToS value for packet. usin g the ToS value name or a decimal valee ranging from 0 to 15.

0 0

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