Message-ID: <D181361D7C86D011925700805FFE898E01971624@spybem01.nap.spyglass.com> From: "Adams, Glenn" <email@example.com> To: "'firstname.lastname@example.org'" <email@example.com> Cc: firstname.lastname@example.org Date: Tue, 10 Nov 1998 11:28:22 -0600 Subject: URI Requirements 1. Under your recent URI requirements document, you have: Given a URI, it must be possible for a receiver to determine the time period(s) within which the resource can be retrieved from the (also resolved) location. Do you intend by this that the information to resolve such a determination should be present in the URI directly? Or that in combination with some unspecified higher-level-protocol, e.g., SAP, SDP, etc., the URI may be used as a key to resolve such a determination? If you mean the former, then this requirement goes beyond the standard semantics of, say, HTTP URLs, which have no intrinsic temporal validity outside of the scope of querying an origin server, etc., for the resource and being informed it is no longer present, etc. 2. Regarding: A URI should be resolvable under any of the following network access conditions: ... The actual resource's retrieved content data may differ in terms of content quality, performance, and edit version. and Ideally, the URI should support referencing various instantiations of the same content (quality/compression ratio, versions/edits). In HTTP's interpretation of URIs, other resource variation axes are provided as well: language, content-encoding, etc. Do you envision these applying in this context? What other variation axes do you anticipate? Glenn Adams Spyglass, Inc.