- They can be parted into these classes as follow according to the principle to realize it: 1. Double Stack(RFC 2893 obsolete RFC 1933):The node adopting the technique runs both IPv4 and IPv6 protocol stacks.
按工作原理可划分为：双协议栈（RFC 2893 obsolete RFC1933）：采用该技术的节点上同时运行IPv4和IPv6两套协议栈。
- He is working double tides to finish his essay.
- I do not realize it is a double feature.
- Double agents live in a perpetual state of fear.
- I want a double room with a view.
- He was so fat that he had a double chin.