租船运输的形式和特点是什么？
You work as a network technician. Your boss is interested in the QoS technology in the context ofvideo traffic. What can be said of application of this technology in this type of network？（） The access layer is the initial point at which traffic enters the network. Traffic is marked （orremarked） at Layers 2 and 3 by the access switch as it enters the network， or is "trusted" that it isentering the network with the appropriate tag。 No traffic marking occurs at the core layer. Layer 2/3 QoS tags are trusted from distributionlayer switches and used to prioritize and queue the traffic as it traverses the core。 Traffic inbound from the access layer to the distribution layer can be trusted or reset dependingupon the ability of the access layer switches. Priority access into the core is provided based onLayer 3 QoS tags。 IP precedence， DSCP， QoS group， IP address， and ingress interface are Layer 2 characteristics that are set by the access layer as it passes traffic to the distribution layer. Thedistribution layer， once it has made a switching decision to the core layer， strips these off。 MAC address， Multiprotocol Label Switching （MPLS）； the ATM cell loss priority （CLP） bit， theFrame Relay discard eligible （DE） bit， and ingress interface are established by the voicesubmodule （distribution layer） as traffic passes to the core layer。 The distribution layer inspects a frame to see if it has exceeded a predefined rate of trafficwithin a certain time frame， which is typically a fixed number internal to the switch. If a frame isdetermined to be in excess of the predefined rate limit， the CoS value can be marked up in a waythat results in the packet being dropped。
刘易斯拐点
引起火灾和爆炸的常见点火源有哪些？
下面属于医疗器械不良事件的有（）。 耗材超出有效期，使用老化引起的故障。 医疗器械性能、功能故障或损坏，并且导致或可能导致伤害。 在产品标签、使用说明书中存在错误或缺陷。 产品刻度、内径等标识错误。
我党在集中精力进行经济建设的同时，必须（），不断巩固马克思主义在意识形态领域的指导地位。
