The network layer provides services to the transport layer. It can be based on either(71). In both cases,its main job is (72) packets from the source to the destination. In network layer,subnets can easily become congested,increasing the delay and(73)for packets. Network designers attempt to avoid congestion by proper desing,Techniques include (74) policy,caching,flow control,and more. The next step beyond just dealing with congestion is to actually try to achieve a promised quality of service. The methods that can be used for this include buffering at the client,traffic shaping,resource(75),and admission control. Approaches that have been designed for good quality of service include integrated services (including RSVP), differentiatd services, and MPLS.
空白处(73)应选择()
A.lowering the throughput
B.lowering the correctness
C.lowering the effectiveness
D.lowering the preciseness
A.进度曲线法
B.网络图法
C.直方图法
D.相关图法
A.确定风险来源
B.确定风险条件
C.描述风险特征
D.制定风险对策
A.署名权
B.出版权
C.版权
D.专有权