On Wed, 3 Sep 2003, Michael Thomas wrote: > Michael Richardson writes: > I despair that it will not be till way too late > that we discover -- unsurprisingly -- that flash > crowds and IP brownouts are not only possible, but > to be expected. More's the pity that we have both > the standards and the deployed code (RSVP) to largely > avoid this disaster in the making. This overstates things by quite a bit. RSVP is not up to the task in a very significant way. Not only is RSVP not scalable (in similar ways that affect Multicast), but even assuming those problems were solved, which is possible, even given an ideal labatory setting, RSVP does't solve the problem, RSVP is not "too heavy". It doesn't work. Not even a little bit. Assuming every router in the path played RSVP, there are two show-stopper problems: It can't detect a network failure, and the path might change for other reasons, so traffic is flowing places where resources weren't reserved. For RSVP to work, every router, end to end has to use it. If ISPs used RSVP between ISPs, some provider somewhere else would be able to really screw up your network. (Just like multicast routing) RSVP was a good try, but not a production solution. > I think that there's some belief that this is a > technical problem with RSVP (too heavy, too > whatever), but I think that's a gloss: signaled > QoS is just plain hard and heavy and slow and all > kinds of other unpleasant things by its very > nature. No technical solution is going to make it > into diffserv or best effort. So we're going to > have a disaster and then Congress will do what the > industry couldn't... > > Mike > >