51、某學(xué)校為學(xué)生宿舍部署無(wú)線網(wǎng)絡(luò)后，頻繁出現(xiàn)網(wǎng)速慢、用戶無(wú)法登陸等現(xiàn)象，網(wǎng)絡(luò)管理員可以通過(guò)哪些措施優(yōu)化無(wú)線網(wǎng)絡(luò)（ ）。

①AP功率調(diào)整②人員密集區(qū)域更換高密AP③調(diào)整寬帶④干擾調(diào)整⑤饋線入戶

A、 ①②

B、 ①②③

C、 ①②③④

D、 ①②③④⑤

52、服務(wù)虛擬化使用分布式存儲(chǔ)，與集中共享儲(chǔ)存相比，分布式存儲(chǔ)（ ）。

A、虛擬機(jī)磁盤IO性能較低

B、建設(shè)成本較高

C、可以實(shí)現(xiàn)多副本數(shù)據(jù)冗余

D、網(wǎng)絡(luò)帶寬要求低

53、某網(wǎng)絡(luò)建設(shè)項(xiàng)目的安裝階段分為A、B、C.D四個(gè)活動(dòng)任務(wù)，各任務(wù)順次進(jìn)行，無(wú)時(shí)間上重疊，各任務(wù)完成時(shí)間估計(jì)如下圖所示，按照計(jì)劃評(píng)審技術(shù)，安裝階段工期估算為（ ）天。

A、31

B、51

C、53

D、83

54、IPsec,also known as the internet Protocol( )，defines the architecture for security services for IP network traffic IPsec describes the framework for providing security a the IP layer,as well as the suite of protocols designed to provide that security:through_( )_and encryption of IP network packets.IPec can be used 10 protect network data,for example,by setting up circuits using IPsec( ),in which all data being sent between two endpoints is encrypted,as with a Virtual( )Network connection ;for encrypting application layer data ;and for providing security for routers sending routing data across the public internet.Internet traffic can also be secured from host to host without the use of lPsec,for example by encryption at the( )layer with HTTP Secure(TTPS)or an the transport layer wit the Transport Layer Security (TLS)protocol.

A、Security

B、Secretary

C、Secret

D、Secondary

A、encoding

B、authentication

C、decryption

D、packaging

A、 channel

B、 path

C、 tunneling

D、 route

A、pubic

B、private

C、personal

D、proper

A、network

B、transport

C、application

D、session