Subject: Re: Future of TCP/IP?
To: Dennis Ferguson <dennis@Ipsilon.COM>
From: Rob Healey <rhealey@altair.helios.mn.org>
List: current-users
Date: 12/21/1995 10:25:42
> > What plans are being made for the inevitable end of available ip addresses?
> > From what I've been hearing from the internic and mci engineers, there are
> > no class A or B IP's left, and there is a rapidly shrinking number of class
> > C's left. 
> 
> I think you misunderstood.  I count 81 of the 126 usable class A networks
> as being reserved, and about half of the 16k class B networks.  The thing
> is that the Internic no longer assigns class A or B numbers to anyone
> at all.  The best you can do is a variable-length block of class C addresses.
> 
	Actually, from the backbone point of view Class based networks are
	already history. A network is now defined by the mask associated
	with the network number so there is no longer class A, B, C. Newer
	IP stacks are also going to classless networks and most routers
	run classless capable software.

	By ditching classes you are free to use the whole 32 bit range
	however you please, and more importantly for the backbone, you
	can aggregate huge numbers of addresses in one route record.

	The bigger problem isn't running out of addresses, it's melting
	down the backbone routers due to too many routes. Classless networks
	help ALOT toward easing this real threat.

		-Rob