ipv4和ipv6什么区别_什么是IPv6？为什么重要？
ipv4和ipv6什么区别
IPv4 addresses on the public Internet are running low. Microsoft paid $7.5 million for Nortel’s 666,624 IP addresses when Nortel went bankrupt in 2011 – that’s over $8 an IP address. IPv4 has technical problems, and IPv6 is the solution.
公用Internet上的IPv4地址即将用尽。 当北电于2011年破产时，微软以750万美元的价格收购了北电的666,624个IP地址，即每个IP地址超过8美元。 IPv4存在技术问题，而IPv6是解决方案。
Unfortunately, deployment of IPv6 has been put off for too long. Had IPv6 been implemented years ago, the transition from the older standard to the newer one would have gone much more smoothly.
不幸的是，IPv6的部署推迟了太长时间。 如果IPv6在多年前实施，那么从旧标准到新标准的过渡将会更加顺利。
Image Credit: Bob Mical on Flickr
图片信用： Flickr上的Bob Mical
IPv4的技术问题 (Technical Problems with IPv4)
In 1980, Internet Protocol version 4 addresses were defined as 32-bit numbers. This provided a total of 232 IPv4 addresses – that’s 4 294 967 296, or 4.2 billion, addresses. This may have seemed like a lot of addresses back in 1980, but today there are many more than 4.2 billion network-connected devices on the planet. Of course, the number of devices connected to the Internet will only continue to grow. To make matters worse, some of these IPv4 addresses are reserved for special cases, so the Internet has fewer than 4.2 billion publically routable IPv4 addresses available to it.
在1980年，Internet协议版本4地址被定义为32位数字。 这样一共提供了2 32个IPv4地址，即4 294 967 296或42亿个地址。 这似乎可以追溯到1980年，但如今，地球上有超过42亿个网络连接设备。 当然，连接到Internet的设备数量只会继续增长。 更糟的是，其中某些IPv4地址是为特殊情况保留的，因此，Internet可用的公开路由的IPv4地址少于42亿个。
There aren’t anywhere near enough publically routable addresses available for every device on the Internet to have a unique one. One thing that’s helped is network-address translation (NAT), which most home networks use. If you have a router in your home, it takes a single publically routable IP address from your Internet service provider and shares it amongst the networked devices in your home. To share the single IPv4 address, it creates a local area network, and each networked device behind the router has its own local IP address. This creates problems when running server software and requires more complicated port forwarding.
互联网上的每台设备都没有足够的公共可路由地址来拥有唯一的地址。 帮助的一件事是大多数家庭网络使用的网络地址转换(NAT)。 如果您家中有一个路由器，它将从您的Internet服务提供商处获得一个可公共路由的IP地址，并在您家中的网络设备之间共享它。 为了共享单个IPv4地址，它创建了一个局域网，并且路由器后面的每个联网设备都有其自己的本地IP地址。 这在运行服务器软件时会产生问题，并且需要更复杂的端口转发。
Carrier-grade NAT is one solution – essentially, every computer using an Internet service provider would be on a local network specific to that ISP. The ISP itself would implement network-address translation, just like a home router. Individuals wouldn’t have publically routable IP addresses and running some forms of server software that requires incoming connections wouldn’t be possible.
运营商级NAT是一种解决方案–本质上，使用Internet服务提供商的每台计算机都将位于该ISP专用的本地网络上。 ISP本身将像家用路由器一样实现网络地址转换。 个人将没有公共可路由的IP地址，并且无法运行某些形式的需要进入连接的服务器软件。
Image Credit: Jemimus on Flickr
图片来源： Flickr上的Jemimus
IPv6如何解决问题 (How IPv6 Solves the Problems)
To avoid the future exhaustion of IPv4 addresses, IPv6 was developed in 1995. IPv6 addresses are defined as 128-bit numbers, which means there are a maximum of 2128 possible IPv6 addresses. In other words, there are over 3.402 × 1038 IPv6 addresses – a much larger number.
为了避免将来IPv4地址耗尽，IPv6于1995年开发。IPv6地址定义为128位数字，这意味着最多可以有2 128个IPv6地址。 换句话说，有超过3.402×10 38个IPv6地址–数量大得多。
In addition to solving the IPv4 address depletion problem by providing more than enough addresses, this large number offers additional advantages – every device could have a globally routable public IP address on the Internet, eliminating the complexity of configuring NAT.
除了通过提供足够多的地址来解决IPv4地址耗尽问题外，这一庞大的数目还具有其他优势-每个设备都可以在Internet上具有全球可路由的公用IP地址，从而消除了配置NAT的复杂性。
Image Credit: Justin Marty on Flickr
图片信用： Flickr上的贾斯汀·马蒂
那么什么是阻止？(So What’s the Hold Up?)
IPv6 was finalized in 1998, 14 years ago. You might assume that this problem should have been solved long ago – but this isn’t the case. Deployment has been going very slowly, in spite of how long IPv6 has been around. Some software is still not IPv6 compatible, although much software has been updated. Some network hardware may also not be IPv6 compatible – while manufacturers could release firmware updates, many of them would rather sell new, IPv6-ready hardware instead. Some websites still do not have IPv6 addresses or DNS records, and are only reachable at IPv4 addresses.
IPv6于14年前于1998年完成。 您可能以为这个问题应该早就解决了，但事实并非如此。 尽管IPv6部署了多长时间，但部署进展非常缓慢。 尽管已经更新了许多软件，但某些软件仍不兼容IPv6。 某些网络硬件也可能与IPv6不兼容-尽管制造商可以发布固件更新，但许多制造商宁愿出售支持IPv6的新硬件。 某些网站仍没有IPv6地址或DNS记录，只能通过IPv4地址访问。
Given the need to test and update software and replace hardware, IPv6 deployment has not been a priority for many organizations. With enough IPv4 address space available, it’s been easy to put IPv6 deployment off until the future. With the imminent exhaustion of available IPv4 addresses, this concern has become more pressing. Deployment is ongoing, with “dual-stack” deployment easing the transition – modern operating systems can have both IPv4 and IPv6 addresses at the same time, making deployment smoother.
鉴于需要测试和更新软件以及替换硬件，IPv6部署并不是许多组织的优先事项。 有了足够的IPv4地址空间，就很容易将IPv6部署推迟到将来。 随着可用IPv4地址即将用尽，这种担忧变得更加紧迫。 部署正在进行中，“双栈”部署简化了过渡–现代操作系统可以同时具有IPv4和IPv6地址，从而使部署更加顺畅。
ipv4和ipv6什么区别