Steve Silverman writes:
The problem with allocating numbers sequentially is the impact on
routers and routing protocols.
The problem with not doing so is that a 128-bit address doesn't
provide anything even remotely close to 2^128 addresses.
You have to choose what you want.
I have heard that the Japanese issue house numbers chronologically.
When you find the right block, you have to hunt
for the right number. What you are suggesting is similar. You would
have as many routing table entries as hosts in the world. The router
would not be affordable. The traffic for routing entries would swamp
the net. The processing of these
routing advertisements would be impossible. It doesn't scale!
Variable address length scales, and it never runs out of addresses,
but nobody wants to do that, even though telephones have been doing it
The function of an address is to enable a router to find it. That is
why we try to use hierarchical addressing even at the cost of numbering
In that case, assign addresses to points in space, instead of devices.
An office occupying a given plot of land will have an IP address space
that is solely a function of the space it occupies. Routing would be
the essence of simplicity and blazingly fast.
IMO one problem of the Internet is that it isn't hierarchical enough.
Consider the phone system: country codes, area codes ... This makes
the job of building a switch much easier. I think we should have
divided the world into 250 countries. Each country into 250
"provinces". Yes, it would waste address space but it would make
routing much easier and more deterministic.
With a variable address length that can extend infinitely at either
end, the address space would never be exhausted. That's how
Yes this would mean a mobile node needs to get new addresses as it
moves. So what. We already have DHCP. Cell phones do a handoff
I agree. We also have DNS.
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