Intel 1520 User Manual
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Intel NetStructure Cache Appliance Administrator’s Guide
✔ The
min-fresh
field, sent by clients, is an acceptable freshness tolerance.
The client wants the object to be at least this fresh. If a cached document does
not remain fresh at least this long in the future, it is revalidated.
not remain fresh at least this long in the future, it is revalidated.
✔ The
max-stale
field, sent by clients, permits the appliance to serve stale
documents provided they are not too old. Some browsers might be willing to
take stale documents in exchange for improved performance, especially
during periods of poor Internet availability.
take stale documents in exchange for improved performance, especially
during periods of poor Internet availability.
The appliance applies
Cache-Control
servability criteria after HTTP freshness
criteria. For example, a document might be considered fresh, but if its age is
greater than its
greater than its
max-age
, it is not served.
Configuring HTTP freshness options
You can configure the following freshness guidelines for the Intel NetStructure
Cache Appliance:
Cache Appliance:
✔ How often to revalidate (when to consider objects stale). See Configuring
HTTP revalidation below.
✔ Whether to use an upper boundary to determine if the Last-Modified / Date
freshness limit is too long.
✔ What absolute freshness lifetime to use when estimating the freshness of
documents without
Expires
or
Last-Modified
headers.
Configuring HTTP revalidation
The following HTTP revalidation options are available:
✔ Always revalidate (everything is considered stale).
✔ Never revalidate (everything is considered fresh).
✔ Revalidate all objects without
Expires
headers. Evaluate the freshness of
objects with
Expires
headers by first checking the
Expires
header, and
then checking
Cache-Control
headers.