您的 Internet 服务提供商可能会通过 DHCP 协议推送 DNS 服务器信息（当然，您可以在计算机本地覆盖此信息）。这就是您的计算机配置 DNS 服务器以启动查询的方式。
CDN 的工作方式如下：依赖基于 CDN 的内容交付的公司将通过 CDN 提供商管理其域。当请求例如域 D 时，计算机将联系其配置的 DNS 服务器，并将被定向到相关域 D 的“权威实体”。从此时起，CDN DNS 服务器可以回复一个答案，该答案提供与请求发起位置“最接近”的 IP 地址的绑定。
除其他事项外，“最接近”属性是根据请求机器的 IP 地址确定的。尽管如此，基于此信息分配“度量”仍然很重要：“IP地址”和“物理位置”之间没有直接关联，而“物理位置”是向请求机器提供尽可能最佳内容的重要信息。
Your Internet Service Provider will likely push the DNS server information through the DHCP protocol (of course, you can override this information locally on your machine). This is how your machine will get configured with DNS servers to launch queries against.
The way a CDN works is as follows: companies relying on CDN based delivery of their contents will manage their domains through a CDN provider. When a request comes for say domain D, a machine will contact its configured DNS server and will be directed to the "authoritative entity" for the domain D in question. From this point, the CDN DNS server can reply with an answer that provides a binding to an IP address "closest" to where the request originated.
The property "closest" is determined, amongst other things, based on the requesting machine's IP address. It is nonetheless non-trivial to assign a "metric" based on this information: there is no direct correlation between "IP address" and "physical location", vital information for effecting as best as possible contents to the requesting machines.
这通常是通过将相同的 IP 地址分配给世界各地域的多个权威 DNS 服务器，并在互联网无默认区域中使用路由来实现一些技巧，以便每个请求都发送到最近的服务器（以网络跳数来衡量） ，而不是英里）。这称为“IP 任播”。然后，不同的服务器可以提供提供商想要的任何答案。这是一个很好的解决方案，因为网络拓扑对性能的影响比物理距离更重要。
This usually works by assigning the same IP address to a number of authoritative DNS servers for the domain around the world, and playing some tricks with routing in the internet default-free zone such that every request goes to the closest server (measured in network hops, not miles). This is called 'IP Anycast'. The different servers can then deliver whatever answers the provider wants them to. It's a good solution because network topology matters much more to performance than physical distance.
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您的 Internet 服务提供商可能会通过 DHCP 协议推送 DNS 服务器信息（当然，您可以在计算机本地覆盖此信息）。这就是您的计算机配置 DNS 服务器以启动查询的方式。
CDN 的工作方式如下：依赖基于 CDN 的内容交付的公司将通过 CDN 提供商管理其域。当请求例如
域 D时，计算机将联系其配置的 DNS 服务器，并将被定向到相关域D的“权威实体”。从此时起，CDN DNS 服务器可以回复一个答案，该答案提供与请求发起位置“最接近”的 IP 地址的绑定。除其他事项外，“最接近”属性是根据请求机器的 IP 地址确定的。尽管如此，基于此信息分配“度量”仍然很重要：“IP地址”和“物理位置”之间没有直接关联，而“物理位置”是向请求机器提供尽可能最佳内容的重要信息。
Your Internet Service Provider will likely push the DNS server information through the DHCP protocol (of course, you can override this information locally on your machine). This is how your machine will get configured with DNS servers to launch queries against.
The way a CDN works is as follows: companies relying on CDN based delivery of their contents will manage their domains through a CDN provider. When a request comes for say
domain D, a machine will contact its configured DNS server and will be directed to the "authoritative entity" for the domainDin question. From this point, the CDN DNS server can reply with an answer that provides a binding to an IP address "closest" to where the request originated.The property "closest" is determined, amongst other things, based on the requesting machine's IP address. It is nonetheless non-trivial to assign a "metric" based on this information: there is no direct correlation between "IP address" and "physical location", vital information for effecting as best as possible contents to the requesting machines.
这通常是通过将相同的 IP 地址分配给世界各地域的多个权威 DNS 服务器，并在互联网无默认区域中使用路由来实现一些技巧，以便每个请求都发送到最近的服务器（以网络跳数来衡量） ，而不是英里）。这称为“IP 任播”。然后，不同的服务器可以提供提供商想要的任何答案。这是一个很好的解决方案，因为网络拓扑对性能的影响比物理距离更重要。
This usually works by assigning the same IP address to a number of authoritative DNS servers for the domain around the world, and playing some tricks with routing in the internet default-free zone such that every request goes to the closest server (measured in network hops, not miles). This is called 'IP Anycast'. The different servers can then deliver whatever answers the provider wants them to. It's a good solution because network topology matters much more to performance than physical distance.