问题 问答题 简答题

在AS内部BGP报文的AS_PATH属性不变,从一个IBGP邻居学习的路由不通告给另外一个IBGP邻居,这样就避免出现路由环路。但是,路由反射器会把从一个客户(IBGP邻居)学习的路由通告到另外一个IBGP邻居,AS_PATH也不变,这就有可能产生环路,此时BGP是如何避免路由环路的?

答案

参考答案:

1、路由反射器使用两个BGP路径属性:ORIGINATOR_ID和CLUSTER_LIST。

2、ORIGINATOR_ID是本地AS内路由发起者的ROUTERID,RR不会把一条路由公布给路由发起者,如果发起者收到了一个带有自身ROUTERID的更新消息,不会处理该消息。

3、当RR收到一个更新消息的时候,会检查CLUSTER_LIST,如果在该列表中发现了自己的clusterid,就知道出现了环路,不会接收该消息。

填空题
阅读理解

阅读理解。

     Saving money gives you freedom (自由). If you have enough savings you may be able to give up your

job. I know a couple (夫妻) who saved up enough money that they were able to leave their jobs for a year,

and travel across the country. You could see the wonderful experiences they had because they were able

to enjoy that time together.

     Saving money is improving your future life. It is important to realize that by saving money now you will

be able to do so many more things in your later years. You can retire early and spend time traveling around

the world. By saving money now, you wil be able to do as many things as you like and enjoy a good life.

     Saving money wil bring you peace of mind. Every dolar that you have in the bank is a dolar, which stands

between you and disaster (灾难). People who have savings are not worried when a car breaks down, or

someone becomes sick. They know that they wil be okay if they lose a job, and it takes time to find a new

one.

     Saving money sets an example for your children. By teaching your children to save money and plan for

the future, you are in control of (掌控) where you spend your money, and what you do with it. It may be

one of the most important ideas that you teach your children.

1. According to paragraph (段落)1, if you want to give up your job, ______. [ ]

A.you can travel across the country

B.you must have enough savings

C.you can stay with your family

D.you wil have wonderful experiences

2. Paragraph 2 tells us that by saving money ______. [ ]

A.you should do more things in the future

B.it is easier for you to retire whenever you wish to

C.it will be possible for you to have a better future life

D.you will never do the things you don't like

3. Paragraph 3 mainly tells us ______. [ ]

A.not to lose a job if you don't have savings

B.to put the money in the bank when you have savings

C.not to worry if a car breaks down or someone is ill

D.to save money if you want to have a peaceful mind

4. Paragraph 4 mainly talks about ______. [ ]

A.the plan for future life

B.the importance of children's education

C.the influence of saving money on children

D.the skills of saving money for children

5. The best title (标题) for this passage may be ______.[ ]

A.Money saving importance

B.Money saving purpose

C.Money saving skills

D.Money saving experience