Subject: Re: Sequentially assigned IP addresses--why not?

From: "Steven M. Bellovin" <[email-masked]>
Date: Thu, 10 Aug 2000 18:41:42 -0400

In message <[email-masked]>, "Cor
zine, Gordie" writes:
>Using the IP address, you index into a table with 100 M entries, pick up an
>index into the 75K entry routing table.  You now have two tables that
>require maintenance, that's all.  If customer changes ISP, their entry in
>the first table is changed.  Link is down, the second table's mechanisms
>handle it. Use a 64 bit processor architecture, memory is cheap.
>Re-architecting the Internet is going to become all but impossible.

The issue isn't table lookup; it's the routing table calculation (and, in 
the case of your particular example, the sheer amount of data that has 
to be passed around).  Put another way, how does each router know what 
should be in those 100M entries?
>
>Its a matter of separating routing from identification.

Phrased somewhat differently, there are a lot of people who agree, 
though it's still a controversial notion.  See if you can find a copy 
of draft-ietf-ipngwg-esd-analysis-06.txt (or -05) -- it's a description 
of the best worked-out proposal, plus a refutation of it.   (I disagree 
with the refutation, but I'm not going to go into that now -- I think 
that the proposal is sound.)  Briefly, the idea is to use the 
high-order 8 bytes of the v6 address for inter-site routing, and the 
low-order 8 bytes for host id.)

But that still requires hierarchical assignment and routing for the 
high-order 8 bytes.  *No one* knows how to do it any differently.
>
>Look, my days as an engineer are a distant memory, so I won't try to work
>this out in detail.

Mere assertions that it is possible, in the face of the prevailing 
wisdom that it isn't, just won't cut it.  Maybe you're right, maybe it 
can be done -- and if so, it won't be the first time that the accepted 
wisdom is wrong.  But the 

>  Maybe there are irrefutable reasons why this can't be
>done, but I do believe the current architecture will lead to premature
>exhaustion of the address space.

Apart from the fact that 128 bits is Really Big, v6 is supposed to have 
easy renumbering, so that we can renumber sites as they're move around 
to different pieces of the topology.

		--Steve Bellovin

---

From: "Anthony Atkielski" <[email-masked]>
Date: Fri, 11 Aug 2000 04:57:23 +0200

> *No one* knows how to do it any differently.

I have an idea:  Let's merge IP addresses with telephone numbers.  A person
will have one IP address for each telephone number he owns, and vice versa,
and the two numbers will be the same.  Because the identifying number of a
telephone is open-ended at both the front and back of the number, there is
no limit to the number of addresses that can be accommodated, and the
addresses can be used for routing without any danger of exhausting the
address space.

Example:  My machine would be, say,

.............85794...  to people on my block
..........44785794...  to people in my city
.......37744785794...  to people in my state
.....1737744785794...  to people outside my country
...421737744785794...  to people on Mars
.................401.  to other machines on my home LAN
.................4015  to the subnet of machine 402 on my home LAN

The digits in common between the two machines are not explicitly specified.
The address space extends to infinity in both directions.

The addressing scheme would locate the starting digit and the number of
significant digits, so my full address would be any of the following:

32768-00004-4015
32768-00003-401
32744-00015-421737744785794
32767-00008-94015487

The scheme would allow for starting digits and lengths in excess of 1-65534.
The starting digit would be a plus or minus offset, allowing infinite
expansion in either direction (there would be no root, but there would be a
level 0).

I want to talk to a machine in Zumbalu.  It's address is
32744-00016-4216849200420283:

...4216849200420283.. Zumbalu
...4217377447857940.. me
...xxx6849200420283.. strip out common digits

I connect to 32747-00013-6849200420283.

I want to talk to my next-door neighbor.  Her address is
32740-00020-04754217377447858662:

04754217377447858662. Jane
04754217377447857940. me
xxxxxxxxxxxxxxxx8662. strip out common digits

I connect to 32766-00004-8662.

I have three physical routes from my machine; I select the one with the
highest starting digit that is equal to or lower than the start digit of my
destination address:

R1 = 32768 = nope, too high
R2 = 32740 = OK
R3 = 32000 = too low

Obviously other details can be worked out.  This is just back-of-envelope
stuff.  The important thing is that there is unlimited room for expansion.
Additionally, individual nodes in the network need only really know about
their immediate neighbors.  You wouldn't need worldwide root servers or
anything like that.

---

From: Lloyd Wood <[email-masked]>
Date: Fri, 11 Aug 2000 11:41:19 +0100 (BST)

On Fri, 11 Aug 2000, Anthony Atkielski wrote:

> I have an idea:  Let's merge IP addresses with telephone numbers. 

You can already type a dot quad on any existing telephone handset, by
say 4#17#168#6*. This obvious fact has been shockingly underutilised.

Using this could allow a dialler to set up a connection via a telco
gateway (which uses an IP address from a pool if you haven't paid
the extra to get a permanent IP address allocated to your phone) to a
designated VoIP port at the endhost with the address of the IP no you
typed.

(If there's no response on any VoIP port, the gateway can try port 80
and starts reading you a webpage, so you're into the usual expected
automated response menu system with zillions of pointless options and
no chance of ever reaching a real human being. To surf the web from
your old POTS phone, you'll have to rely on the phone company
providing a printed directory of selected DNS A records once a year.)

The beauty of that approach is that if you've identified your phone to
the telco gateway at service activation as being in the 4.17 subnet
for convenience purposes (same building/near the network, etc.),
168#6* will suffice. Hey, local numbers are shorter, and we've just
reinvented the company PABX with trendy IP dialtone.

Dot quads are about as hard to remember as phone numbers are, so
no change there - until IPv6 takes off, anyway.

L.

and everyone will see the value permanent addresses!

<[email-masked]>PGP<http://www.ee.surrey.ac.uk/Personal/L.Wood/>

---

From: Fred Baker <[email-masked]>
Date: Fri, 11 Aug 2000 09:16:15 -0700

At 04:57 AM 8/11/00 +0200, Anthony Atkielski wrote:
>and the two numbers will be the same.

great idea. When I build a telephone out of an IP dialler attached to 
someone's waist, a modulator on their necklace, and an earphone attached to 
their earring, all connected by IP on BlueTooth, what addresses do I put on 
the different components of the telephone?

But we're still mixing addresses and numbers. An address gives you 
topological location; a name translates to an address. All the games you 
want to play with expanding and extending the telephone number are games 
with the name. We still need an address.