问题 单项选择题

在交换机上实现VLAN,可以采用静态或动态的方法。下面关于静态VLAN的描述中,正确的是()。

A.把交换机的各个端口固定地分配给VLAN

B.可以根据MAC地址来建立静态VLAN

C.可以根据网络层协议来建立静态VLAN

D.可以根据IP广播域来建立静态VLAN

答案

参考答案:A

解析:

在交换机上实现VLAN,可以采用静态的或动态的方法。

静态分配VLAN:为交换机的各个端口指定所属的VLAN。这种基于端口的划分方法是把各个端口固定地分配给不同的VLAN,任何连接到交换机的设备都属于接入端口所在的VLAN。如果用户改变了接入端口而又想访问原来的VLAN,则需要为该VLAN增加新的端口成员。

动态分配VLAN:动态VLAN通过诸如CiscoWorks2000之类的软件包来创建,可以根据设备的MAC地址、网络层协议、网络层地址、IP广播域或管理策略来划分VLAN。根据MAC地址划分VLAN的方法应用最多,一般交换机都支持这种方法。

无论一台设备连接到交换网络的任何地方,接入交换机通过查询VLAN管理策略服务器(VLAN Management Policy Server,VMPS),根据设备的MAC地址就可以确定该设备的VLAN成员身份。这种方法使得用户可以在交换网络中改变接入位置,而仍能访问所属的VLAN,但是当用户数量很多时,对每个用户设备分配VLAN的工作量是很大的管理负担。

基于网络层协议划分VLAN,需要分析各种协议的地址格式并进行相应的转换,因此需要更多的处理开销。相比利用MAC地址划分VLAN,这种方法在处理速度上不占优势。

多项选择题
阅读理解

People in the United States honor their parents with two special days: Mother’s Day, on the second Sunday in May, and Father’s Day, on the third Sunday in June.

Mother’s Day was proclaimed a day for national observance by President Woodrow Wilson in 1915. Ann Jarvis from Grafton, West Virginia, had started the idea to have a day to honor mothers. She was the one who chose the second Sunday in May and also began the custom of wearing a carnation.

In 1909, Mrs. Dodd from Spokane, Washington, thought of the idea of a day to honor fathers. She wanted to honor her own father, William Smart. After her mother died, he had the responsibility of raising a family of five sons and a daughter. In 1910, the first Father’s Day was observed in Spokane. Senator Margaret Chase Smith helped to establish Father’s Day as a national commemorative day in 1972.

These days are set aside to show love and respect for parents. They raise their children and educate them to be responsible citizens. They give love and care.

These two special days are celebrated in many different ways. On Mother’s Day people wear carnations. A red one symbolizes a living mother. A white one shows that the mother is dead.Many people attend religious services to honor parents. It is also a day when people whose parents are dead visit the cemetery. On these days families get together at home, as well as in restaurants. They often have outdoor barbecues for Father’s Day. These are days of fun and good feelings and memories.

小题1:According to the passage, which of the following about the second Sunday in May is

NOT true?

A.It is a day to show love to mothers

B.It is a day to wear carnations

C.It is a day for people to visit the cemetery

D.It is a day for many people to attend religious services小题2:Choose the right time order of the following events.

a. The first Father’s Day was observed.

b. Mother’s Day was proclaimed a day for national observance

c. Father’s Day became a day for national observance. 

d. The idea of honoring fathers was brought up

A.a b c d

B.d a b c

C.b a c d

D.d a c b小题3:Who plays the most important role in Father’s Day becoming a national commemorative day?

A.Mrs. Do

B.Margaret Chase Smith

C.Ann Jarvis

D.Woodrow Wilson小题4:From the passage, we know in the U.S. ________________.

A.one should wear a red carnation if one’s mother pass away

B.on Mother’s Day, families often go out to have barbecues

C.on Father’s Day, people often stay at home to celebrate the special day.

D.The purpose to have these two special days is to show love to parents小题5:The author’s purpose of writing this passage is to __________

A.call on people to love and respect their parents

B.introduce Mother’s Day and Father’s Day.

C.tell the difference between Mother’s Day and Father’s Day

D.show how important fathers and mothers are