问题 多项选择题

下面关于烽火分组传送网保护方式说法正确的是()。

A.LSP1:1保护的是同源同宿的主备路VP径,通过Y1731或BFD来检测

B.PW冗余保护是对主备两个宿节点失效进行保护,是对L2VPN的保护,需要启用VC层OAM,在和LSP1:1叠加时,一般需要设置拖延时间快于LSP1:1

C.VPNFRR是一种L3VPN保护技术,保护倒换发生时实际上是基于内层标签的

D.IPFRR原理本质上是在转収平面存在到同一个目的地有两条不同的路由,也就是两个不同的下一跳,一个为主,一个为备

答案

参考答案:A, C, D

阅读理解与欣赏
阅读理解

Until late in the 20th century most Americans spent time with people of different generations. Now middle-aged Americans may not keep in touch with old people until they are old themselves.

That's because we group people by age. We put our three-year-olds together in day-care centers, our 13-year-olds in schools and sport activities, and our 80-year-olds in senior citizen homes. Why?

We live far away from the old for many reasons. Young people sometimes avoid the old to get rid of fears of aging and dying. It is much harder to watch someone we love disappear before our eyes. Sometimes it`s got hard that we stay away from the people who need us the most.

Fortunately, some of us have found our way to the old. And we have discovered that they often save the young.

A reporter moved her family into a block filled with old people. At first her children were disappointed. But the reporter baked banana bread for the neighbors and had her children deliver it and visit them. Soon the children had many new friends, with whom they shared food, stories and projects. "My children have never been lonely, "the reporter said.

The young, in turn, save the old. Once I was in a rest home (养老院)when a visitor showed up with a baby, she was immediately surrounded. People who hadn't gotten out of bed in a week suddenly were ringing for a wheelchair. Even those who had seemed asleep woke up to watch the child. Babies have an astonishing power to comfort and cure.

Grandparents are a special case. They give their grandchildren a feeling of security and continuity. As my husband put it "My grandparents gave me a deep sense that things would turn out right in the end." Grandchildren speak of attention they don't get from worried parents. "My parents were always telling me to hurry up, and my grandparents told me to slow down," one friend said. A teacher told me she can tell which pupils have relationships with grandparents: they are quieter, calmer and more trusting.

67. Now in an American family, people can find that___________.

A. children never live with their parents                            

B. not all working people live with their parents

C. aged people are supported by their grandchildren    

D. grandchildren are supported by their grandparents

68. Seeing a baby, the old people got excited because _______.

A. they had never seen a baby before                        B. the baby was clever and beautiful                   

C. the baby brought them the image of life              D. the baby's mother would take care of them           

69. Why are some children quieter, calmer and more trusting ?

A. Because they have relationships with their grandparents.                 

B. Because their worried parents ask them to act like that.

C . Because they have nothing to worry about.                                 

D. Because their teachers ask them to act like that.

70. Which of the following can show the fact that the old often save the young?

A. The old can become friends of the children and the children may not feel lonely.

B. The old get excited when they see a baby.

C. The old can cure the young when they are sick.

D. Babies have an astonishing power to comfort and cure.

BCAA