From kragen@dnaco.net Mon Aug 31 11:30:29 1998 Date: Mon, 31 Aug 1998 11:30:28 -0400 (EDT) From: Kragen To: jakob@useit.com Subject: spam and multicast Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII X-Keywords: X-UID: 1603 Status: O X-Status: I see you've put your mail address back on your web pages. I take it the obfuscation route didn't ward off spam? (I've been getting a fair bit of spam these days.) On the death of TV: you've said a couple of times that there's absolutely no reason for Star Trek to come on at 9:00 of you're ready for it at 8:43, that this is just an artifact of old technology. I think it's actually an artifact of limited bandwidth, which will be a problem into the foreseeable future. If I'm watching Star Trek starting at 9:00, and my neighbor is watching it starting at 8:59, the broadcaster has to send out every packet of the show twice, a minute apart. If there are ten million people watching Star Trek (and there are already), all starting at different times, that means each packet has to be sent out ten million times. If bandwidth costs money, which it will for a while, it will be seven orders of magnitude less expensive to simply multicast the show at a specified time. Many publishers of bandwidth-intensive things like video may find this a compelling difference, and choose multicast. The reason for the difference in cost is that, with multicast, the production of multiple copies of the video is done as close to the ultimate destination as possible, so only one copy ever goes over a particular link, regardless of how many people want to receive it. Usenet also works this way, or used to, and didn't suffer the time constraints that IP multicast does, as it was a store-and-forward system, that you fetched articles from asynchronously. Perhaps Usenet-like technologies will provide a middle way that can achieve your vision. What do you think? Kragen -- Kragen Sitaker We are forming cells within a global brain and we are excited that we might start to think collectively. What becomes of us still hangs crucially on how we think individually. -- Tim Berners-Lee, inventor of the Web