Quality of Service (QoS): Managing Bandwidth More Effectively

Using QoS Types To Configure QoS for Outbound Traffic

Figure 6-10shows an example of the ToS byte in the header for an IPv4 packet, and illustrates the diffserv bits and precedence bits in the ToS byte. (Note that the Precedence bits are a subset of the Differentiated Services bits.)

Field:

Destination

Source MAC

802.1Q Field

Type &

ToS Byte

 

 

MAC Address

Address

 

Version

 

 

 

 

 

 

 

 

 

 

 

Packet:

FF FF FF FF FF FF

08 00 09 00 00 16

08 00

45

E 0

...

 

 

 

 

 

 

 

 

 

Differentiated Services Codepoint

Precedence

 

 

 

Rsvd.

 

 

Bits

 

 

 

 

 

 

 

 

 

 

 

 

 

 

1

1

1

0

0

0

0

0

 

 

 

 

 

 

 

 

 

 

E

 

 

 

0

 

 

 

 

 

 

 

 

 

Figure 6-10. The ToS Codepoint and Precedence Bits

6-27