O The diffserv approach to providing QoS in networks employs a small,well-defined set of building blocks from which you can build a variety of(71).Its aim is to define the differentiated services(DS)byte,the Type of Service(ToS)byte from the Internet Protocol Version 4(72)and the Traffic Class byte from IP Version 6,and mark the standardized DS byte of the packet such that it receives a particular forwarding treatment,or per-hop behavior(PHB),at each network node.The diffserv architecture provides a(73)within which service providers can offer customers a range of network services,each differentiated based on performance.A customer can choose the(74)level needed on a packet-by-packet basis by simply marking the packet's Differentiated Services Code Point(DSCP)field to a specific value.

       This(75)specifies the PHB given to the packet within the service provider network。

       (71)A services  B.Users  C.networks  D.structures

       (72)A message  B.Packet  C.header  D.package

       (73)A.information  B.Structure  C.means  D.framework

       (74)A.performance  B.Secure  C.privacy  D.data

       (75)A.packet  B.value  C.service  D.Paragraph