【判断题】
PON是一种点到点结构的单纤双向光接入网络,其典型拓扑结构为树型。
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【判断题】
在接入技术中,VDSL2,G.SHDSL,GPON,EPON,E1,T1是可以实现上下行速率对称的接入技术,ADSL,ADSL2+不是上下行速率对称的接入技术。
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可以通过DBA技术在PON中实现OLT和ONT之间上行和下行的动态带宽分配,从而实现流量控制。
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1G-EPON系统可使用两种物理层接口类型有1000BASE-PX20和1000BASE-PX30。
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可以通过命令行对静态MAC地址进行老化操作,并能老化静态MAC地址成功。
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一块PON业务板卡可以同时接入EPON和GPON的ONU。
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对于ONU设备和用户设备之间的距离在100m-500m之间,可以建议客户采用FTTB中LAN+POTS接入的方案。
【判断题】
VLAN ID的取值范围是从0~4096。
【判断题】
OLT网管上可以支持对ONU光模块工作温度(operating temperature)、供电电压(supply voltage)等指标的读取和监测。
【判断题】
OLT和ONU之间的二层隔离功能是指,OLT设备上同一PON口下和和不同PON口下的各ONU之间均不应通过OLT设备上的二层桥接功能直接互通。
【判断题】
IEEE 802.1Q协议里定义了VLAN Stacking功能,描述了基于LLID、CVLAN ID、EtherType、和CVLAN优先级标签等字段映射到SVLAN ID。
【判断题】
PON系统下行方向采用广播发送的数据流传输方式,上行方向采用基于统计复用的时分多址接入技术。
【判断题】
IGMPV1版本相比V2版本,主要的缺陷在于V1路由器感知用户的离开有较大的延迟。
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同一个组播应用的接收者必须处于同一个大网络中,但可以只是这个网络中的一部分主机。
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每个PON口下只要光功率允许就可以无限多个ONU。
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GPON协议中业务的最小承载单位是T-cont,而不是GEM port。
【判断题】
连接光纤时请勿直视接头,以免眼睛被激光灼伤。
【判断题】
OLT和ONU互通解耦是指一个厂商的OLT下可以实现对异厂商的ONU的业务接入。
【判断题】
智能网关支持智能OS软件平台。基于智能OS软件平台可以开发插件,扩展家庭智能网关的功能。
【判断题】
在TCP/IP协议栈里,层次越高的报文越小。
【判断题】
交织信道的作用是让数据能够正确地抵达接收端,在交织信道中,以延长等待时间为代价,换取传输数据的正确性。
【判断题】
在开通线路中根据线路的实际情况调整上下行目标噪声裕度。如果线路质量好,那么目标噪声裕度可以设小一些以获得高的速度;如果线路质量差,那么应该设的大一些以获得高的稳定性。
【判断题】
与STP(屏蔽双绞线)相比,UTP(非屏蔽双绞线)具有重量轻、灵活性好、安装方便、成本低等特点。只要平衡与接地良好,UTP与STP有相同的电磁兼容性。因而UTP应用更为广泛,构成了用户环路的主体。
【判断题】
多模光纤中心玻璃芯较粗(50或62.5μm),可传多种模式的光。但其模间色散较大,这就限制了传输数字信号的频率,而且随距离的增加会更加严重。因此,多模光纤传输的距离就比较近,一般只有几公里。
【判断题】
单模光纤(Single Mode Fiber):中心玻璃芯很细(芯径一般为9或10μm),只能传一种模式的光。因此,其模间色散很小,适用于远程通讯。
【判断题】
带外网管的组网方式无需另外组建一套专用的网管网络,组网更加灵活、方便。
【判断题】
EPON是百兆的PON技术,而GPON是千兆的PON技术。
【判断题】
GPON支持的最大光分路比为1:64,EPON支持的最大光分路比为1:32。
【判断题】
EPON和GPON具有相同的拓扑结构,不同的封装格式。
【判断题】
EPON中,当LLID的mode值为1时,表示该下行数据帧是发送给每个ONU的。
【判断题】
GPON TC层规定了5种类型的T-CONT。
【判断题】
在EPON系统中,新加入的ONU必须等待OLT的发现帧才能进行答复。
【判断题】
E/GPON技术中下行采用的是广播的方式,上行采用TDMA方式
【判断题】
在PON系统中,ODN可以是有源的,也可以是无源的。
【判断题】
BSSID实际上就是AP的MAC地址,用来标识AP管理的BSS,在同一个AP内BSSID和SSID一一映射。
【判断题】
SIP是对等协议,H.248是非对等协议。
【判断题】
由于多模光纤可传输多种模式信号使传输容量倍增,所以该光纤在长途传输中得到广泛应用。
【判断题】
EPON的各个ONU/ONT可以动态使用上行带宽。
【判断题】
无线路由器能够实现跨网段通信,并配置DHCP业务。
【判断题】
多个胖AP组网时,每个AP默认发射相同名称的无线SSID,并支持无线漫游。
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16. I think eating more vegetables is good _______ our health.
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A. at, to B. for, with C. to, to D. for, to
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Sorry, I ______ with my friends at that time.
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—________exciting news! We shall try our best to support it.
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— Nothing _______. He was in his usual shirt and jeans.
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( ) 26.With help from a Mr. H, you can__________.
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( ) 27. A PENGO WATCH CONTROL can help you to ______________.
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( ) 28. You can get your Mr. H for___________.
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( ) 29. When was canned food invented?
A. In 1870. B. In 1810. C. In 1902. D. In 1926.
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( ) 30. After the trip to the Arctic, Clarence Birdseye invented ____________.
A. canned food B. can openers
C. frozen food D. air conditioning
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( ) 31. Changes in weather _____________ in Willis Carrier's company.
A. helped to keep food B. made rooms comfortable
C. caused health problems D. hurt printing paper
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( ) 32. According to the passage, which of the following may lead to inventions?
A. People's needs. B. Public support.
C. Modern technology. D. Practical suggestions.
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( ) 33. What is the writer's main purpose(目的)in writing this passage?
A.To tell the readers his life story.
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D. To let people know how poor he was.
【单选题】
( ) 34. Why did the father not ask his son not to do this and do that?
A.Because he felt quite confident of his son.
B.Because he was born from a poor family.
C.Because he was a man of few words.
D.Because he didn't want to be much too strict with his son.
【单选题】
( ) 35. What would someone learn from this passage?
A.How to live by oneself. B.How to stand on one's own feet.
C.What a good father should do. D.What the self-important is like.
【单选题】
( ) 36. What may be the proper Chinese for the underlined part in the passage?
A.闲暇时光 B.学费 C.精神空虚 D.经济不足
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( ) 37. The Chinese Yellow Sea Wetlands are in the _______ of China.
A.south B.east C.west D.north
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( ) 38. Usually the weather in the wetlands is _______.
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( ) 39. The World Wetlands Day is on _______.
A.February 2 B.June 25 C.April 22 D.March
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( ) 40. We must protect wetlands because _______.
A.they are home for wildlife B.they can prevent flood
C.they can offer food to the animals and birds D.all of the above
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) 1. —Is it far from here to the bank?
—Not very, only________.
A. 20 minute’s walk B. 20 minutes walk
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2. — After discussing, the students ________ some good ideas to work on the project.
— Thats great!
A. put up B. set up C. caught up with D. came up with
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3. Yesterday Tommy walked past my table and ______ my bowls and dishes.
He should be careful next time.
A. knocked off B. took off C. showed off D. turned off
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4.We don’t have enough nurses to look after patients.At least ___ nurses are needed.
A. ten another B. more ten C. another ten D. other ten
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5. — Zhao Rui, it’s said that many famous singers will come to Yangzhou on April 18th. How about watching the evening show there?
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— .I only want to go to Qingdao.
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11. When the parents arrived at the hall, the students _______ their projects.
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14. — Can he jump high?
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