豆知识 2010-12-26&2011-01-01 认识IPv6 (2/2)

 IPv6 is designed to meet the requirementsof the potentially huge Internet expansion. It will allow a return to a globalenvironment where the addressing rules of the network are transparent¹ to theapplications again. Through autoconfiguration and plug-and-play support,network devices will be able to connect to the network without manual configurationand without any bootstrap services, such as DHCP service. 

 

 

 

IPv6 succeeds in doing this by providingthe following benefits to network and IT professionals.

 

 

 

First, IPv6 has a larger address spacefor global reachability and scalability. This will result in an almostunlimited number of IP addresses and a hierarchical network architecture forrouting efficiency. This eliminates the problems associated with NET. The abilityto provide global addresses for each network device and enables end-to-endreachability. And network management will be simpler and easier. 

 

 

 

Second, a simplified header format² forefficient packet handling. 6 of the 12 IPv4 header fields have been removed inIPv6. Some IPv4 fields have been carried over with modified names and some newfields have been added to improve efficiency and introduce new features. 

 

 

 

Third, a hierarchical networkarchitecture for routing efficiency, that follows some of the IPv4 CIDR principles. 

 

 

 

Another important IPv6 benefit is theembedded security with mandatory³ IPsec implementation⁴. While the use of IPsecis optional in IPv4, IPsec is mandatory in IPv6. IPsec is part of the IPv6protocol suite⁶.

 

Therefore, network implementerscould enable IPsec in every IPv6 node, potentially making the networks moresecure. 

 

 

 

Additionally, IPv6 offers an increasednumber of multicast addresses. IPv6 will not use broadcast, leading to a more performant network. 

 

 

 

Moreover, in IPv6 the ICMP protocol⁵ hasbeen revised. ICMP version six has become much more powerful and includes newfunctions to support autoconfiguration, neighbor discovery and multicasting. 

 

 

 

And finally, IPv6 offers built-inmobility as the anticipated large rollout of wireless⁷ data services is a keyIPv6 driver.

1 transparent   

adj.明显的，无疑的；透明的

参考例句：

• The water is so transparent that we can see the fishes swimming.水清澈透明，可以看到鱼儿游来游去。
• The window glass is transparent.窗玻璃是透明的。

2 format   

n.设计，版式；[计算机]格式，DOS命令:格式化(磁盘)，用于空盘或使用过的磁盘建立新空盘来存储数据；v.使格式化，设计，安排

参考例句：

• Please format this floppy disc.请将这张软盘格式化。
• The format of the figure is very tasteful.该图表的格式很雅致。

3 mandatory   

adj.命令的；强制的；义务的；n.受托者

参考例句：

• It's mandatory to pay taxes.缴税是义务性的。
• There is no mandatory paid annual leave in the U.S.美国没有强制带薪年假。

4 implementation   

n.实施，贯彻

参考例句：

• Implementation of the program is now well underway.这一项目的实施现在行情看好。

5 protocol   

n.议定书，草约，会谈记录，外交礼节

参考例句：

• We must observe the correct protocol.我们必须遵守应有的礼仪。
• The statesmen signed a protocol.那些政治家签了议定书。

6 suite   

n.一套(家具)；套房；随从人员

参考例句：

• She has a suite of rooms in the hotel.她在那家旅馆有一套房间。
• That is a nice suite of furniture.那套家具很不错。

7 wireless   

adj.无线的；n.无线电

参考例句：

• There are a lot of wireless links in a radio.收音机里有许多无线电线路。
• Wireless messages tell us that the ship was sinking.无线电报告知我们那艘船正在下沉。