IPv4 address shortage? Really?

Steven Bellovin smb at cs.columbia.edu
Tue Mar 8 06:37:27 CST 2011

> ...well, kind of. What you don't mention is that it was thought to be
> ugly and rejected solely on the aesthetic grounds.  Which is somewhat
> different from being rejected because it cannot work.
> Now, I'd be first to admit that using LSRR as a substitute for
> straightforward address extension is ugly.  But so is iBGP, CIDR/route
> aggregation, running interior routing over CLNS, and (God forbid, for it
> is ugly as hell) NAT.

No.  It  was rejected because routers tended to melt down into quivering
puddles of silicon from seeing many packets with IP options set -- a fast
trip to the slow path.  It also requires just as many changes to applications
and DNS content, and about as large an addressing plan change as v6.  There
were more reasons, but they escape me at the moment.

		--Steve Bellovin, http://www.cs.columbia.edu/~smb

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