Akamai边缘服务器是否共享缓存的内容，或者是否来源？
问题描述：
如果Akamai边缘服务器缓存了一个url，它是否会与其他边缘服务器共享该内容，或者将没有内容缓存的边缘服务器本地返回到原始位置以获取内容？Akamai边缘服务器是否共享缓存的内容，或者是否来源？
我很想拥有官方的Akamai文档，但当然会喜欢任何输入！
请注意，我已经试过了，看看我期望的答案是 - 即使边缘服务器驻留在另一台边缘服务器上，它至少会在某些时间返回来获取内容。
例如，我在整个周末都留了一个curl请求缓存7天的资源，并看到我获得了3个不同的缓存响应（通过响应标题不同），并且可以看到原点一定是访问至少3次，我认为，我也看到很多不同的边缘服务器在我的转储列表中，虽然这是正常的，我认为。
66 a80-12-96-140.deploy.akamaitechnologies.com
65 a204-237-142-14.deploy.akamaitechnologies.com
51 a204-237-142-44.deploy.akamaitechnologies.com
38 a80-12-96-230.deploy.akamaitechnologies.com
8 a65-158-180-197.deploy.akamaitechnologies.com
6 a23-58-92-92.deploy.akamaitechnologies.com
6 a23-58-92-39.deploy.akamaitechnologies.com
5 a65-158-180-190.deploy.akamaitechnologies.com
5 a64-145-68-25.deploy.akamaitechnologies.com
5 a64-145-68-15.deploy.akamaitechnologies.com
4 a65-158-180-180.deploy.akamaitechnologies.com
4 a204-141-247-173.deploy.akamaitechnologies.com
4 a204-141-247-143.deploy.akamaitechnologies.com
2 a66-110-100-23.deploy.akamaitechnologies.com
1 a72-37-154-53.deploy.akamaitechnologies.com
1 a23-61-206-205.deploy.akamaitechnologies.com
1 a205-185-195-182.deploy.akamaitechnologies.com
答
我没有得到一个答案在这里，所以I posted this same question on the Akamai Community Forums，并得到了Neil Jedrzejewski以下响应，在Akamai的高级解决方案架构师。谢谢尼尔！
First of all, which edge server answers a request will vary over time based on
our low-level mapping system and load in a specific network region. Don't read
too much into the fact that you get many different edge servers - swapping them
in and out is part and parcel of how we give our customers scale and
availability.
To answer your question about shared caching, a high level explanation goes like
this.
When a client makes a request our mapping system will return the IP address(es)
of an edge server best located to honour the request. These edge servers are
grouped together in what we call network "regions". If a specific edge server
receives a request and cannot fulfil it from it's own cache, it will send out
a broadcast message (ICP) on it's back-plane asking if any other edge machine
peers in the same region has the object. The timeout for a response to this
request is very short (as the request is local) and if a peer has it, it will
pass the request to the peer and served the response before caching it
locally.
If no local peer is able to satisfy the request, the edge machine will them go
forward to it's cache parent as a new client request and the parent will attempt
to satisfy the request (again, checking with it's own ICP peers), serving the
object out of cache to the edge machine. The edge machine will then serve it
back to the client and cache it locally for next time. If the object is
unavailable or invalid (read: TTL expired) along the entire cache hierarchy
chain, then yes, it will go back to origin to re-validate or reacquire the
object.
An important point to remember is that caching is "best effort" only. Although
your TTL for an object was 7 days, that is simply an instruction to the cache on
how long to consider the content "fresh" and a valid response for a request.
However it is not a guarantee that the object will remain in a servers cache.
Objects can and will drop out of cache if they are infrequently requested or due
to other operational factors. This is where ICP and parent caches help because
they help consolidate requests. So although an object may drop out of a specific
edge cache, it may well still be in the cache parent as many edges are passing
requests through it thus giving a high cache-hit ratio.
So in short, our caching system. Will use different edge machines to respond to
a request over time based on our mapping systems insight into which machine will
best serve the client request. Will ask a local peer if it has a copy of an
object if it cannot satisfy the request itself. Will forward the request to a
cache parent if necessary to fulfil the request. Will go back to origin for the
object if the object is "stale" or if itself, a peer or parent cannot satisfy
the request.
Hope that helps.