On Mon, 08 Aug 2011 10:15:17 +0200, Mohacsi Janos said: > - Home users - they usually don't know what is subnet. Setting up > different subnets in their SOHO router can be difficult. Usually the > simple 1 subnet for every device is enough for them. Separating some > devices into a separate subnets is usually enough for the most > sophisticated home users. If not then he can opt for business service....
You don't want to make the assumption that just because Joe Sixpack doesn't know what a subnet is, that Joe Sixpack's CPE doesn't know either. And remember that if it's 3 hops from one end of Joe Sixpack's internal net to the other, you're gonna burn a few bits to support heirarchical routing so you don't need a routing protocol. So if Joe's exterior-facing CPU gets handed a /56 by the provider, and it hands each device it sees a /60 in case it's a device that routes too, it can only support 14 devices. And if one of the things that got handed a /60 is a wireless access point or something, it's only going to be able to support 15 or so subnets. So a simple topology of only a half dozen devices can burn up 8 bits of subnet addressing real fast. Yes, you can conserve bits by being more clever, but then you probably need an IGP of some sort....
pgp3hzjjr0ugC.pgp
Description: PGP signature
