问题 单项选择题

以下关于网络结构的描述中,错误的是()。

A.核心层网络用于连接分布在不同位置的子网,实现路由汇聚功能

B.汇聚层根据接入层的用户流量进行本地路由、安全控制、流量整型等处理

C.核心层设备之间、核心层设备与汇聚层设备通常采用冗余链路的光纤连接

D.接入层网络用于将终端用户计算机接入到网络中

答案

参考答案:A

解析:

本题考查网络规划设计中的分层架构的相关知识。通常网络系统采用分层的设计思想,有利于分配规划带宽,均衡负荷,提高网络效率。

其中,核心层网络用于连接服务器集群,各建筑物子网交换路由以及网络出口等;汇聚层网络用于连接分布在不同位置的子网,实现路由汇聚功能;接入层网络用于将终端用户计算机接入到网络中。通常情况下,核心层设备之间、核心层设备与汇聚层设备通常采用冗余链路的光纤连接。

填空题
单项选择题

American Museum of Natural History is one of the largest natural and historic museums in the world and one of the main natural history research and education centres in the United States, set up in 1869 and located in the west of the Central Park, Manhattan District, New York. It (1) 7 hectares in its total area, (2) classical types of buildings. The (3) of ancient creatures and humanity is (4) the first place of all the museums in the world, (5) the representative samples from South America, Africa, Europe, Asia and Australia were collected, besides those from the (6) country, the United States.

In the museum, there are five kinds of exhibits, including astronomy, mineralogy, human history, and animals in the (7) times and those in modern times. There are thirty-eight exhibition halls with different (8) from 500 to 1,500 square metres. Besides these, there is a Roosevelt Memorial Hall in (9) of President Roosevelt who supported the (10) of the museum, which is also used to have a special exhibition, showing the new important (11) on natural sciences and (12) affairs and social problems, and special topics connected closely with the life of the citizens. Besides this, it is also used for avocation (13) to have all kinds of scientific activities in the laboratories, centres of natural science and centres for citizens. There are more than 10 (14) research departments mainly (15) for collection of samples, research and work of publication.

In the museum, there are (16) and sub-libraries of Aulspond ancient amniote, with about 300 thousand books and magazines (17) natural history, many of (18) are very valuable monographs for the first edition. It has published many expert books and magazines, and a large number of propaganda materials, (19) which are the two magazines, Natural History and Members of Museum that have the biggest (20) of their magazines.

1()

A.explores

B.demonstrates

C.expands

D.covers