Real World Computing

Everyone is accustomed to thinking about file-sharing programs as being the villains of the piece in any network. ISPs keep watch on their traffic, unwary users end up sharing far more than they were expecting or discovering that a preliminary poke-about has made their machine a member of a quasi-hidden sharing club that bursts through their bandwidth cap for the month within a couple of days. Corporates tend to hear about these kind of programs around the water cooler, or in incomprehensible support calls while rolling out a home-worker initiative. Yet it's taken at least three years of widespread use of "music download programs" or "P2P sharing" for an example to come my way of a bit of genuine business use for this technology, and once you start to think about it the idea makes a massive amount of sense.

Whenever a company network goes through the deployment of a new release of some product (and here I'm thinking much more about vertical market databases than the latest OS patch from Microsoft), there can often arise a bad case of the weakest link. Sure, you can leave the 100MB update self-extractor on your hidden software share (please tell me that all your Nerd software is on a share whose name ends with a $, right?), but then as you dance merrily round the building clicking the mouse to start the ball rolling it takes only a slight divergence from a neat, flat network topology for the bottlenecks to become painfully apparent. Copy 100MB to ten workstations and you might not notice it at all. Copy to 30 and you'll definitely see a slowdown. Copy to 40 with three of them on Gigabit and watch as the different speeds produce lockouts. On one badly tuned network, I started 36 machines copying from a central source, while the 37th was on a Gigabit link - the other 36 machines all stopped mid-copy and then claimed a read error. Now magnify this problem by having a multibuilding site, or even just two buildings separated by a few hundred metres of fibre, which is easily nasty enough to turn a two-hour job into all weekend.

It's under conditions like this that modern, grown-up P2P file-sharing program such as Azureus can step in and be a massive help. Once one client has completed a download of a file published via Azureus, other nearby clients can use it as a server, so that eventually the whole download process takes on the aspect of a kind of giant networking Mexican Wave, with the emphasis on minimising network traffic at larger scales by using local hubs and switches to share the load.

Of course, it isn't simply a matter of double-clicking on the installer and rolling out your corporate build images over this platform. In particular, your version control and new-patch announcement system has to be mediated by a reasonably simple intranet site. But as a classic example of beating a burglar's jemmy into a ploughshare, I've yet to see a smarter piece of innovation.

	1 P2P's not inherently evil.