On Wed, Mar 27, 2002 at 04:56:32PM -0800, [EMAIL PROTECTED] wrote: > I got the impression (maybe wrong) that guntella as it exists is > something much worse than a tree, that connections are > pretty much haphazard and when you send out a query it reaches > the same node by multiple paths, and that you really need the > query ID to keep from forwarding massive duplicates.
I think you're right and that's how it works, which is why it scales badly as the search messages flooded seven hops deep into the randomly organized network even with duplicate suprresion based on query-id (or whatever they use), end up consuming some significant proportion of the network bandwidth. The other problem apparently is that for a low bandwidth node (eg dialup) the searches can saturate your link, so you can hardly do anything but receive and answer search queries. Apparently there are some hacks to reduce this problem, but Gnutella's other big problem is that there are lots of independent clients so some of the problems come from interoperability problems, bugs etc. And gnutella is not able to resume a transfer that dies part way through which is very bad for download reliability. FastTrack/Kazza (but no longer Morpheus since the Kazza / Morpheus fall-out) on the other hand can resume, and in fact do multiple simultaneous downloads from multiple nodes having the same content so that it gets the content both much faster and much more reliably. Also helps cope with different link speeds as a group of slow nodes or asymmetric bandwidth nodes (like cable with fast down but limited up) can satisfy the download of cable and other broadband users. There's a nice write-up about the gnutella's problem's on openp2p.com [1]. Contrary to what article [2] claims FastTrack/Kazza really does blow Gnutella away, the supernode concept with high performance nodes elected to be search hubs makes all the difference. Gnutella last I tried it was barely functional for downloads, ~95% of downloads failed, and searches were much slower. Adam [1] Gnutella: Alive, Well and Changing Fast, by Kelly Truelove http://www.openp2p.com/pub/a/p2p/2001/01/25/truelove0101.html [2] Gnutella Blown Away? Not Exactly, by Serguei Osokine http://www.openp2p.com/pub/a/p2p/2001/07/11/numbers.html
