Why couldn't MAC addresses be used instead of IPv4|6 for networking?

Typically, MAC is assigned by the hardware manufacturer (sometimes you can change/spoof it). IP is typically assigned either by the network administratior or DHCP. If all addresses were based on mac, you could easily intercept the messages from anyone. IP allows a layer of abstraction in which you can group multiple subnets into the same external IP or set up subnets within those subnets even.

Another problem is that numerous devices will share the same MAC address, it's just statistically unlikely to find them on the same network. It's an especially big problem with cheap/knockoff network equipment. See: http://www.linuxquestions.org/questions/linux-networking-3/m...

That's pretty much exactly what IPv6 with stateless autoconfig does--network address in the upper 64 bits, MAC address (slightly modified) in the lower 64.

They already are. Part of the IPv6 address is derived from your MAC.

Despite not owning the network for which they are being allocated, IPv4 is a "paying job" to some people. And sometimes an ego boost too, i.e., people who get their kicks from creating "IP address policy". Needless to say this easy "work." Hello ARIN.

It's a lot like ICANN.

On CircleID someone recently pointed out that IPv6 will make this sort of "job" meaningless. There is so much IPv6 address space that playing favorites and charging hefty fees is unjustifiable.

Back to your point about MAC's: This is also why the "we're out of IP addresses" meme seems silly. Because we don't see the IEEE complaining they are "running out of MAC's". And IPv6 addresses use MAC's.

The thing to keep in mind is that just because something, e.g. a better addressing scheme, or true network-level peer-to-peer networking, is not "widely adopted" does not mean it isn't available, _right now_. It may have been available for years. There were people at universities still teaching the use of punch cards even after a well-known computer professional in Canada was already programming using a terminal display. And there were other Canadians sending emails before DARPA.

Do not assume that the crowd is always wise. And be wary of the "hype".

80/20 rules - another great internet meme - mean than we can have 80% of the people being stupid. And the 20% have to suffer.

When the "new" naming, "new" addressing and "new" peer-to-peer solutions are offered up the next time, keep an open mind. Try not to be so quick to dismiss any sort of change to the "status quo". Evaluate the approach carefully. It might have merit, and maybe it's not immediately obvious.

Many times (in fact almost all the time), the solutions are not new. We're just waiting for people to finally catch on and realize there is "a better way". We're waiting for people to "try something 'new'".

This is one of the reasons why IPX was a bad idea and never took off. Automagical discovery is always great until it doesn't work.

> If all addresses were based on mac, you could easily intercept the messages from anyone.

So you encrypt stuff you don't want anyone else to read. Security isn't the concern of the networking layers; it's all done, to the extent it is done, at the application layer.

That's the original design, anyway.

Edited to add: Well, the original original designs were by people who weren't thinking of security at all. That's why telnet and FTP are the way they are.

> Another problem is that numerous devices will share the same MAC address, it's just statistically unlikely to find them on the same network.

This, on the other hand, really is a perversion of the intended model. 48 bits was intended to be globally unique.