Sun Certified Solaris(tm) 9 System and Network Administrator All-in-One Exam Guide

Quality of service (QoS) is very much a missing component of IPv4. When IPv4 was developed, there was no such thing as mission critical e-commerce data being exchanged between organizations on the Internet. However, with the rise of B2B e-commerce and the development of digital virtual enterprises , ensuring QoS is critical to the operation of certain classes of applications and services (such as Web Services).

IPv6 provides QoS through a priority and flow label system of packet prioritization defined within the packet header. There are several different priority values that have been suggested for congestion-controlled traffic, which has a lower priority than noncongestion-controlled traffic:

• Unclassified

• 1 Bulk traffic

• 2 Noninteractive bulk data transfer

• 3 Undefined

• 4 Interactive bulk data transfer

• 5 Undefined

• 6 Interactive nonbulk data transfer

• 7 Control traffic