Network Working Group R. Fielding Request for Comments: 2616 ...

understand.For example, consider a hypothetical new response directive calledcommunity which acts as a modifier to the private directive. Wedefine this new directive to mean that, in addition to any non-sharedcache, any cache which is shared only by members of the communitynamed within its value may cache the response. An origin serverwishing to allow the UCI community to use an otherwise privateresponse in their shared cache(s) could do so by includingCache-Control: private, community="UCI"A cache seeing this header field will act correctly even if the cachedoes not understand the community cache-extension, since it will alsosee and understand the private directive and thus default to the safebehavior.Fielding, et al. Standards Track [Page 116]RFC 2616 HTTP/1.1 June 1999Unrecognized cache-directives MUST be ignored; it is assumed that anycache-directive likely to be unrecognized by an HTTP/1.1 cache willbe combined with standard directives (or the response's defaultcacheability) such that the cache behavior will remain minimallycorrect even if the cache does not understand the extension(s).14.10 ConnectionThe Connection general-header field allows the sender to specifyoptions that are desired for that particular connection and MUST NOTbe communicated by proxies over further connections.The Connection header has the following grammar:Connection = "Connection" ":" 1#(connection-token)connection-token = tokenHTTP/1.1 proxies MUST parse the Connection header field before amessage is forwarded and, for each connection-token in this field,remove any header field(s) from the message with the same name as theconnection-token. Connection options are signaled by the presence ofa connection-token in the Connection header field, not by anycorresponding additional header field(s), since the additional headerfield may not be sent if there are no parameters associated with thatconnection option.