Editing Delta encoding (section)

===Delta encoding in HTTP===
Another instance of use of delta encoding is [https://datatracker.ietf.org/doc/html/rfc3229 RFC 3229], "Delta encoding in HTTP", which proposes that [[HTTP]] servers should be able to send updated Web pages in the form of differences between versions (deltas), which should decrease Internet traffic, as most pages change slowly over time, rather than being completely rewritten repeatedly:

{{blockquote|This document describes how delta encoding can be supported as a compatible extension to HTTP/1.1.

Many HTTP (Hypertext Transport Protocol) requests cause the retrieval of slightly modified instances of resources for which the client already has a cache entry. Research has shown that such modifying updates are frequent, and that the modifications are typically much smaller than the actual entity. In such cases, HTTP would make more efficient use of network bandwidth if it could transfer a minimal description of the changes, rather than the entire new instance of the resource.

[...] We believe that it might be possible to support rsync using the "instance manipulation" framework described later in this document, but this has not been worked out in any detail.
}}

The suggested rsync-based framework was implemented in the ''rproxy'' system as a pair of HTTP proxies.<ref>{{cite web |title=rproxy: introduction |url=https://rproxy.samba.org/index.html |website=rproxy.samba.org}}</ref> Like the basic vcdiff-based implementation, both systems are rarely used.