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    <p>There are more differences than the ones you have identified.</p> <p>Duplex/directional:</p> <ul> <li>Uni-directional: HTTP poll, long poll, streaming.</li> <li>Bi-direcitonal: WebSockets, plugin networking</li> </ul> <p>In order of increasing latency (approximate):</p> <ul> <li>WebSockets</li> <li>Plugin networking</li> <li>HTTP streaming</li> <li>HTTP long-poll</li> <li>HTTP polling</li> </ul> <p>CORS (cross-origin support):</p> <ul> <li>WebSockets: yes</li> <li>Plugin networking: Flash via policy request (not sure about others)</li> <li>HTTP * (some recent support)</li> </ul> <p>Native binary data (typed arrays, blobs):</p> <ul> <li>WebSockets: yes</li> <li>Plugin networking: not with Flash (requires URL encoding across ExternalInterface)</li> <li>HTTP *: recent proposal to enable binary type support</li> </ul> <p>Bandwidth in decreasing efficiency:</p> <ul> <li>Plugin networking: Flash sockets are raw except for initial policy request</li> <li>WebSockets: connection setup handshake and a few bytes per frame</li> <li>HTTP streaming (re-use of server connection)</li> <li>HTTP long-poll: connection for every message</li> <li>HTTP poll: connection for every message + no data messages</li> </ul> <p>Mobile device support:</p> <ul> <li>WebSocket: iOS 4.2 and up. Some Android via Flash emulation or using <a href="https://play.google.com/store/apps/details?id=org.mozilla.firefox&amp;hl=en" rel="noreferrer">Firefox for Android</a> or <a href="https://play.google.com/store/apps/details?id=com.android.chrome&amp;feature=search_result#?t=W251bGwsMSwyLDEsImNvbS5hbmRyb2lkLmNocm9tZSJd" rel="noreferrer">Google Chrome for Android</a> which both provide native WebSocket support.</li> <li>Plugin networking: some Android. Not on iOS</li> <li>HTTP *: mostly yes</li> </ul> <p>Javascript usage complexity (from simplest to most complicated). Admittedly complexity measures are somewhat subjective.</p> <ul> <li>WebSockets</li> <li>HTTP poll</li> <li>Plugin networking</li> <li>HTTP long poll, streaming</li> </ul> <p>Also note that there is a W3C proposal for standardizing HTTP streaming called <a href="http://www.w3.org/TR/eventsource/" rel="noreferrer">Server-Sent Events</a>. It is currently fairly early in it's evolution and is designed to provide a standard Javascript API with comparable simplicity to WebSockets.</p>
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    1. COThanks a lot for the nice reply Kanaka. Can you please tell me why / how http streaming has a higher latency than websockets? maybe with a simple example? thanks a lot.
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    2. CO@SoftwareGuy. Many reasons. On recent browsers, you can use the XMLHTTPRequest onprogress event handler to be notified of data. But the spec says 50ms is the smallest notification interval. Otherwise you must poll for response data. Also, client sends establish a new HTTP connection and so significantly increase round-trip latency. Also, many web servers cut off HTTP connections after 30 seconds or so meaning you often have to keep re-establishing the server push connection. I've seen 5-10ms WebSocket roundtrip latencies on a local network. HTTP streaming latency would likely be 50ms+.
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    3. COThanks a lot for the detailed reply :)
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