HTTP/1.1 200 OK Date: Tue, 14 Feb 2012 09:21:30 GMT Server: Apache/2.2.6 (Fedora) Last-Modified: Mon, 13 Mar 1995 07:37:32 GMT ETag: "73cb9-454-bfd0700" Accept-Ranges: bytes Content-Length: 1108 Connection: close Content-Type: text/html; charset=UTF-8

Enhanced communication model

Reasons PRO

Need more symmetric interaction model.
For randomly updated server information, this will always be better than client polling.

Reasons CON

Most such enhancements require a stateful server (but this can be mitigated by explicitly factoring out the stateful part of the server).

Subsidiary Design Requirements

Server-to-client callbacks .
Session protocols (client-server or peer-to-peer).

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