51、某學校為學生宿舍部署無線網絡后，頻繁出現(xiàn)網速慢、用戶無法登陸等現(xiàn)象，網絡管理員可以通過哪些措施優(yōu)化無線網絡（ ）。

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

A、 ①②

B、 ①②③

C、 ①②③④

D、 ①②③④⑤

52、服務虛擬化使用分布式存儲，與集中共享儲存相比，分布式存儲（ ）。

A、虛擬機磁盤IO性能較低

B、建設成本較高

C、可以實現(xiàn)多副本數據冗余

D、網絡帶寬要求低

53、某網絡建設項目的安裝階段分為A、B、C.D四個活動任務，各任務順次進行，無時間上重疊，各任務完成時間估計如下圖所示，按照計劃評審技術，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