4447f991_P_Guide___HTTP_General_Headers__HTTP_Cache_Control_Directives_HTTP_Message_Type
[Cache-Control Directive] s-maxage [Description] If present, this directive specifies the maximum age for shared caches receiving the response. Private caches (ones that serve only a single client) use the max-age value described just above. [HTTP Message Type] 
Response
R e q u e s t o r R e s p o n s e
R e s p o n s e
R e q u e s t
The TCP/IP Guide - HTTP General Headers
HTTP Message Type