legacy /8

Fri Apr 2 22:46:55 UTC 2010

On Apr 2, 2010, at 3:38 PM, Andrew Gray wrote:

> Jeroen van Aart writes: 
>> Cutler James R wrote:
>>> I also just got a fresh box of popcorn.  I will sit by and wait
>> I honestly am not trying to be a troll. It's just everytime I glance over the IANA IPv4 Address Space Registry I feel rather annoyed about all those /8s that were assigned back in the day without apparently realising we might run out. It was explained to me that many companies with /8s use it for their internal network and migrating to 10/8 instead is a major pain.
> 
> You know, I've felt the same irritation before, but one thing I am wondering and perhaps some folks around here have been around long enough to know - what was the original thinking behind doing those /8s? 

The original thinking was based on an environment where the Internet was expected to consist only of a few corporate entities providing services and products to research institutions and the government. There was no WWW, no browsers, and Windows couldn't even spell TCP/IP at the time.

The expectation was that those /8s would be subnetted into vast arrays of "Class C" sized chunks and that subnets within a given /8 all had to be the same size (this used to be necessary to keep RIP happy and every machine participating in RIP routing had to have an /etc/netmasks (or equivalent) table that tracked "THE" subnet mask for each natural prefix).

Sure, a /8 is a lot of addresses in today's world.  However, back then, it was much like a /48 today. Just a way to give someone 65,500+ subnets (for any given X/8, then X.0/16, X.255/16, X.Y.0/24, X.Y.255/24 were unusable in these days).

> I understand that they were A classes and assigned to large companies, etc. but was it just not believed there would be more than 126(-ish) of these entities at the time?   Or was it thought we would move on to larger address space before we did?  Or was it that things were just more free-flowing back in the day?  Why were A classes even created?  RFC 791 at least doesn't seem to provide much insight as to the 'whys'. 
> - Andrew

It was thought that we would not have nearly so many people connected to the internet.  It was expected that most things connecting to the internet would be minicomputers and mainframes.

Owen