Interesting blog post talking about XMPP and the need for web services to switch from one-way polling mechanisms to two-way synchronisation to achieve scalability – XMPP (aka Jabber) is the future for cloud services (Jive Talks blog).

The common way to communicate on the Internet is one-way polling. If you are waiting for the post to arrive on your doorstep, polling would be the equivalent of you going to the front door every few minutes to see if anything had arrived yet. All trips to the front door are a complete waste of time except for the one that yields success – a pile of post waiting to be opened. Most email systems do actually work like this – regular checks to the server to see if any new email has arrived. It was a good idea when network connectivity was scarce and expensive (and hence is still true for picking up email on your mobile phone, unless you are on an all-inclusive data contract)

The trouble with polling is all those wasted trips when there is nothing to discover. When you’ve got lots of users, say 68 million (the number of active users on Facebook), lots of polling = lots of wasted use of resources. XMPP appears to be one possible alternative. It is based on instant messaging principles – presence information traded between two computers. When one has something to share, they ‘IM’ it to their friend. It’s the equivalent of the postman knowing that some houses prefer it if he yells (or rings the doorbell) to let them know the post has arrived.

I’m grossly over-simplifying and only just delving into this area. But I think it could be a technology to keep an eye on for all sorts of uses. I kept harping on about when will IM come of age. Never saw this coming. Perhaps IM’s age will be the era of cloud computing…


Filed under: Cloud Computing (new library topic)

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