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

From: "Steven M. Bellovin" <[email-masked]>
Date: Fri, 11 Aug 2000 19:48:43 -0400

In message <003b01c003c6$3ffe9230$0a00000a@contactdish>, "Anthony Atkielski" wr
ites:
>> The telephone company has milliseconds to seconds
>> to resolve an address into a route. The Internet
>> has microseconds to nanoseconds to do so.
>
>Build faster hardware.
>
>
We seem to be talking 5-6 orders of magnitude in speed here.  Even 
Moore's Law doesn't help in that range.

		--Steve Bellovin

---

From: "Anthony Atkielski" <[email-masked]>
Date: Sat, 12 Aug 2000 06:38:17 +0200

> We seem to be talking 5-6 orders of magnitude in
> speed here.  Even Moore's Law doesn't help in that range.

I don't see why all this processing power is required.  You look at the
incoming address, you figure out which outbound path can handle that
address, and you forward it.  Simple.  Even if the full address is a
thousand digits long, you only have to look at the digits around your level
to determine the next step in routing.

---

From: "Philip J. Nesser II" <[email-masked]>
Date: Sat, 12 Aug 2000 00:10:26 -0700

Anthony,

Let me try and say this kindly (since after it is pointed out several
hundred times it gets quite frustrating).  If you don't see the
processing requirements then you have *no* understanding of how
routing works.  Forwarding packets is easy.  Routers basically have
two related but completely seperate functions.

The *second* function is to take an incoming packet, look at its
destination address, compare it to its forwarding table, and forward
the packet.  This is easy in the whole scheme of things.

The *first* function is to calculate that forwarding table used
above.  This is the place that processing power is needed.  On busy
routers this calculation can be necessary hundreds of times a second.
 The more routes the larger the process of recalculating the
forwarding table when a change *anywhere* in the topology occurs.

- --->  Phil

P.S.  Go find the CIDRD archives, or (if you want even earlier) try
the big-ip list to see the debate dozens of times.

> -----Original Message-----
> From: Anthony Atkielski [mailto:[email-masked]]
> Sent: Friday, August 11, 2000 9:38 PM
> To: [email-masked]
> Subject: Re: Sequentially assigned IP addresses--why not? 
> 
> 
> I don't see why all this processing power is required.  You look at
> the incoming address, you figure out which outbound path can handle
> that address, and you forward it.  Simple.  Even if the full
> address is a thousand digits long, you only have to look at the
> digits around 
> your level

---

From: "Anthony Atkielski" <[email-masked]>
Date: Sat, 12 Aug 2000 12:44:08 +0200

> Let me try and say this kindly (since after it is
> pointed out several hundred times it gets quite
> frustrating).  If you don't see the processing
> requirements then you have *no* understanding of how
> routing works.

You need not go to great pains to be "kind" about it.  This is a pretty
standard preamble to a post that essentially means "I disagree."

> The *first* function is to calculate that forwarding
> table used above.  This is the place that processing
> power is needed.  On busy routers this calculation can
> be necessary hundreds of times a second.  The more
> routes the larger the process of recalculating the

I wonder how human beings manage to route their cars from one point to
another, given how much more slowly they process things than do routers.

---

From: "Loa Andersson" <[email-masked]>
Date: Sat, 12 Aug 2000 13:35:05 +0200

> another, given how much more slowly they process things than do routers.

Ever given a thought on the amount of effort explorers, cartographrs, 
road builders, maintainers have put into supplying you with the routing
info you need to route your car?

/Loa

-- 

Loa Andersson
Director Routing Architecture Lab, EMEA
St Eriksgatan 115A, PO Box 6701
113 85 Stockholm, Sweden
phone: +46 8 50 88 36 34,   mobile + 46 70 522 78 34
e-mail: [email-masked]

---

From: Måns Nilsson <[email-masked]>
Date: Sat, 12 Aug 2000 14:18:23 +0200

> another, given how much more slowly they process things than do routers.

This is a stupid argument. An IP packet (for instance) relies on
external decision-making (the router) while a car has an intelligent (or
at least decision-making) human inside, making the "car+human" unit
self-supporting in terms of route decision.  

-- 
Måns Nilsson                    DNS Technichian
+46 709 174 840                 NIC-SE
+46 8 545 85 707                MN1334-RIPE

---

From: Henning Schulzrinne <[email-masked]>
Date: Sat, 12 Aug 2000 08:48:35 -0400

> Moore's Law doesn't help in that range.

Also, circuit setup needed for establishing routing labels requires at
least one round trip time (ignoring processing time), which is pretty
much a constant given geographic distance.

-- 
Henning Schulzrinne   http://www.cs.columbia.edu/~hgs

---

From: Mike Bresina <[email-masked]>
Date: Sat, 12 Aug 2000 06:00:29 -0700 (PDT)

> info you need to route your car?
 
Now if they'd find a way to minimize the length of the queues...
 
---------------------------------------
Mike Bresina           ([email-masked])
Senior System Administrator
Systems Engineer
Intellicom Network Operations Center
http://mike.vsat.net/

v.  (925) 245-8888
f.  (925) 606-7273
---------------------------------------

---

From: John Day <[email-masked]>
Date: Sat, 12 Aug 2000 09:49:33 -0400

>another, given how much more slowly they process things than do routers.

Because their cars move *much* slower than packets.

---

From: "Anthony Atkielski" <[email-masked]>
Date: Sun, 13 Aug 2000 01:24:52 +0200

> Ever given a thought on the amount of effort explorers,
> cartographrs, road builders, maintainers have put into
> supplying you with the routing info you need to route
> your car?

No.  I just set the coordinates in my GPS and follow the arrow.  No map
required.

---

From: "Anthony Atkielski" <[email-masked]>
Date: Sun, 13 Aug 2000 01:25:57 +0200

> This is a stupid argument. An IP packet (for instance)
> relies on external decision-making (the router) while
> a car has an intelligent (or at least decision-making)
> human inside, making the "car+human" unit self-supporting
> in terms of route decision.  

So?

---

From: "Anthony Atkielski" <[email-masked]>
Date: Sun, 13 Aug 2000 01:26:53 +0200

> Because their cars move *much* slower than packets.

So do their brains.

---

From: "Philip J. Nesser II" <[email-masked]>
Date: Sat, 12 Aug 2000 16:26:13 -0700

> Sent: Saturday, August 12, 2000 3:44 AM
> To: [email-masked]
> I wonder how human beings manage to route their cars from one point
> to another, given how much more slowly they process things than do
> routers.  
> 

Trying to dismiss a technical problem with a facile analogy that is
not relevant is not a way to pursuade.  Roadways to not change
topology dozens of times per second.  Cars do not travel at a large
percentage of the speed of light so calculating the route to your
corner store usually doesn't involve considering routes through
Denver, New York, Dallas, Chicago, San Jose, Washington DC and
Atlanta all at the same time.  People don't often mathematically
optimize their routes based on traffic flow patterns that are being
inputed from hundreds of sources per second.  I could go on, but what
is the point?

If you want to participate on a mailing list devoted to engineering
of Internet protocols please don't expect to be listened to seriously
unless you are prepared to conduct the discussion on a technical
level.

- --->  Phil

---

From: "Anthony Atkielski" <[email-masked]>
Date: Sun, 13 Aug 2000 01:46:17 +0200

> Trying to dismiss a technical problem with a
> facile analogy that is not relevant is not a way
> to pursuade.

Logically, then, calling the analogy "stupid," or saying "we looked at it
and decided it wouldn't work," is even less so.

In any case, I have no objective to persuade.  I'm sure that all the
decisions have been made.  I'm confident that the passage of time will
provide all the persuasion needed.

> Roadways to not change topology dozens of times
> per second.

It depends on the time scale of observation.

> I could go on, but what is the point?

I agree.

> If you want to participate on a mailing list devoted
> to engineering of Internet protocols please don't
> expect to be listened to seriously unless you are
> prepared to conduct the discussion on a technical
> level.

There are certainly some people who probably should not listen to me, as it
will just raise their blood pressure.  However, there are also others who
are willing to listen to anyone, just as I am.  Those in the former category
can censor at their receiving end, so there is no reason to censor at the
sending end, particularly since it would be to the detriment of people in
the latter category.

Speaking of technical levels, what level does it require to change the
Reply-To address on a mailing list so that replies go to the group by
default, instead of to the sender of whatever message elicits a reply?

---

From: Bill Manning <[email-masked]>
Date: Sat, 12 Aug 2000 18:08:52 -0700 (PDT)

% 
% > Ever given a thought on the amount of effort explorers,
% > cartographrs, road builders, maintainers have put into
% > supplying you with the routing info you need to route
% > your car?
% 
% No.  I just set the coordinates in my GPS and follow the arrow.  No map
% required.
% 

and drive right into the bay over that bridge that your GPS insists
exists.  Where do you think your GPS gets its info?

-- 
--bill

---

From: "Anthony Atkielski" <[email-masked]>
Date: Sun, 13 Aug 2000 04:19:01 +0200

> and drive right into the bay over that bridge
> that your GPS insists exists.

My GPS has no knowledge of bridges.  I look out the window to see if there
are any obstacles.  I just follow drivable paths in the general direction of
the heading shown on my GPS until I arrive.  It is surprisingly efficient,
and I don't need any map at all.

> Where do you think your GPS gets its info?

From satellites overhead.