问题 填空题

根据网络拓扑和需求说明,完成(或解释)路由器R1的配置。
R1#configure terminal ;进入全局配置模式
R1(config)#interrace ethernet0 ;进入端口配嗣模式
R1(config-if)#ip address (3) (4) ;配置端口IP地址
R1(config-if)#ipv6 nat ; (5)
R1(config-if)#interface ethernet1
R1(config-if)#ipv6 address (6) /64
R1(config-if)#ipv6 nat
R1(config-if)#ipv6 access-list ipv6 permit 2001:aaaa::1/64 any ; (7)
R1(config-if)#ipv6 nat prefix (8)
R1(config-if)#ipv6 nat v6v4 pool ipv4-pool (9) (10) prefix-length 24
R1(config-if)#ipV6 nat v6v4 source list ipv6 pool ipv4-pool
R1(config-if)#exit

答案

参考答案:16.23.31.20

解析:由题干关键信息“IPv6网络使用的NAT-PT前缀是2001:aaaa:0:0:0:1::/96,IPv6网络中的任意节点动态映射到地址池16.23.31.10~16.23.31.20中的IPv4地址”可知,本案例采用的是动态NAT-PT操作模式,即通过在路由器R1上使用动态NATHPT配置,IPv6单协议网络节点可以建立到IPv4网络节点的会话。
图1-24所示网络结构图中已给出路由器R1端口E0的IPv4地址参数192.17.5.1/24,即IP地址192.17.5.1、子网掩码255.255.255.0。因此在R1端口E0的IP地址参数配置语句中,(3)空缺处应填入192.17.5.1,(4)空缺处应填入255.255.255.0。
对于(5)空缺处的配置语句解释,在接口配置模式下,配置语句ipv6 nat用于在当前接口上启用NAT-PT机制。
图1-24所示网络结构图中已给出路由器R1端口E1的IPv6地址参数2001:aaaa::1/64,即IPv6地址2001:aaaa::1、前缀长度为64位。因此在R1端口E1的IP地址参数配置语句中,(6)空缺处应填入2001:aaaa::1。
对于(7)空缺处的配置语句解释,在接口配置模式下,配置语句ipv6 access-list ipv6 Dermit2001:aaaa::1/64 any用于配置一个标准的IPv6 ACL,以规定IPv6单协议网络中允许被转换的IPv6地址范围。
题干给出了“IPv6网络使用的NAT-PT前缀是2001:aaaa:0:0:0:1::/96”这一关键信息。而在接口配置模式下,配置语句ipv6 nat prefix<ipv6-address>/96用于声明在IPv6域内NAT-PT使用的IPv6前缀。因此,(8)空缺处应填入2001:aaaa:0:0:0:1::/96。
在接口配置模式下,配置语句ipv6 nat v6v4 pool<natpt-pool-name><start-ipv4-address><end-ipv4-address>prefix-length<prefix-length>用于规定动态NAT-PT转换过程中使用的源IPv4地址池。结合题干关键信息“IPv6网络中的任意节点动态映射到地址池16.23.31.10~16.23.31.20中的IPv4地址”可得,(9)空缺处应填入16.23.31.10,(10)空缺处应填入16.23.31.20。
在接口配置模式下,配置语句ipv6 nat v6v4 source list ipv6 pool ipv4-pool用于配置动态NAT-PT映射。

单项选择题

On the ground floor of the Federal Reserve building in Washington, DC, there is an electronic game which tests a visitor’s skill at setting interest rates. You have to decide how to respond to events such as rising inflation or a stockmarket crash. If you get all the answers right, the machine declares you the next Fed chairman. In real life, because of huge uncertainties about data and how the economy works, there is no obviously right answer to the question of when to change interest rates. Nor is there any easy test of who will make the best Fed chairman. So who would The Economist select for the job

Alan Greenspan will retire as Fed chairman on January 31st, after a mere 181/2 years in the job. So George Bush needs to nominate a successor soon. Mr. Bush has a penchant for picking his pals to fill top jobs: last week he nominated his personal lawyer Harriet Miers to the Supreme Court. But his personal bank manager really would not cut the mustard as Fed chairman. This is the most important economic-policy job in America—indeed in the whole world. The Fed chairman sets interest rates with the aim of controlling inflation, which in turn helps determine the value of the dollar, the world’s main reserve currency. It is hardly surprising that financial markets worldwide can rise or fall on his every word.

Financial markets are typically more volatile during the first year after the handover to a new chairman than during the rest of his tenure. In October 1987,barely two months after Mr. Greenspan took office, the stock market crashed. Current conditions for a handover are hardly ideal. America’s economy has never looked so unbalanced, with a negative household savings rate, a housing bubble, a hefty budget deficit, a record current-account deficit and rising inflation. Figures due on October 14th are expected to show that the 12-monthrate of inflation has risen above 4% —its highest since 1991.

Which of the following, according to the text, is a common phenomenon()

A. Financial markets and stock markets crash due to the handover

B. Comment by the Fed chairman are invalid in the world financial markets

C. Inflation rises above 4% —record high level

D. Remarks by the Fed chairman can sway the world financial markets

单项选择题