Subject: [RRG] End user network size [ [Q] draft-farinacci-lisp: IPv4 address depletion]

From: Brian E Carpenter <[email-masked]>
Date: Wed, 26 Sep 2007 14:46:50 +1200

On 2007-09-26 13:41, Robin Whittle wrote:
...
> My idea is that there are many end-user networks which need less
> than 256 IP addresses and whose owners need or strongly desire their
> networks to be multihomed and/or to be free to move to another ISP
> without renumbering.  

I feel I have to pick this apart to explain why I disagree.

I don't think the owners of such small networks care about
their IP address at all. Their true requirements are

- they want their network to be highly reliable
- they want to be free to move to another ISP without manual intervention

I doubt if many of them are willing to pay a second ISP fee to
obtain reliability; so it's actually their current ISP who has
to provide the reliability, which may well include multihoming
the ISP, but that's at another scale.

I'm sure none of them want to know anything about IP addresses.
Maybe they do need invariant addresses for their printers etc.,
but RFC 1918 or IPv6 ULAs will do just fine for that, and have
nothing to do with their ISP prefix. Whoever installs their
network can set up local addresses for printers. When they
change ISPs, DHCP (or RAs) will invisibly update addresses
for all their systems needing Internet access. It's no different
from when they power cycle their ADSL box today. From my
experience, that's something that typical small offices get
to do every couple of weeks anyway. They don't even notice
that the desktops may get new addresses.

I'm sticking to my analysis that SOHO sized networks are
simply not impacted by the R&A problem. I believe we only
need to worry about significantly larger units, of at
least 1000 hosts, and that sets a less ambitious target.

     Brian

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From: "William Herrin" <[email-masked]>
Date: Tue, 25 Sep 2007 23:29:08 -0400

> their IP address at all. Their true requirements are

Brian,

I run a small operation with two upstream connections via the local
monopolies: Verizon Business Fios and Cox Business cable Internet. I
have around 20 addresses in use between the two, attached to 7
servers. The cost is quite modest: around $150 per month to each
provider for which I get about two T1's worth of bandwidth upstream
and 15 or so T1's worth downstream.

My true requirements are for a small number of addresses which reach
me via whichever of those upstreams is at this moment working, closest
and not too clogged. I can't speak for anyone else but I find it
difficult to credit the notion that my requirements are unusual.

Regards,
Bill Herrin

-- 
William D. Herrin                  [email-masked]  [email-masked]
3005 Crane Dr.                        Web: <http://bill.herrin.us/>
Falls Church, VA 22042-3004

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From: Brian E Carpenter <[email-masked]>
Date: Wed, 26 Sep 2007 16:31:21 +1200

Bill,

> difficult to credit the notion that my requirements are unusual.

They are certainly not unreasonable! But I really think it's the exception;
most SOHO users (I mean 99%) simply won't have the sophistication
to do that sort of thing, and will rely on their ISP. That's what
I see around me.

     Brian

---

From: Tony Li <[email-masked]>
Date: Tue, 25 Sep 2007 21:42:12 -0700

> to do that sort of thing, and will rely on their ISP. That's what

Most SOHO users that I know would like a reciprocal multihoming
agreement with someone nearby using WiFi.

This doesn't dilute your argument, however, as they would still be NATed
into the backup address space.

Of course, the view here is SillyCon Valley is *somewhat* warped.  ;-)

Tony

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From: Eliot Lear <[email-masked]>
Date: Wed, 26 Sep 2007 09:57:22 +0200

Hello,
> I can't speak for anyone else but I find it

I think we need to tease out the SO from the HO.  I suspect that 
behaviors will differ at least in terms of technology adoption lag.  A 
pizza parlor that takes its voice over IP is going to need reliability 
because if it loses connectivity orders don't roll in.  Whether that is 
done by redundancy or by a single highly reliable service will depend on 
the available services and their reputations.  And I think the vote is 
still out on that.

A person sitting at home can get annoyed but is likely to make a 
convenience decision rather than maximizing profit.  Some will, some won't.

Eliot

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From: Stephane Bortzmeyer <[email-masked]>
Date: Wed, 26 Sep 2007 10:21:16 +0200

On Wed, Sep 26, 2007 at 02:46:50PM +1200,
 Brian E Carpenter <[email-masked]> wrote 
 a message of 43 lines which said:

> obtain reliability;

I strongly disagree. Even for a very small company, paying three
different ISP is a small amount of money with current ADSL offers. It
is reasonable from a financial point of view. Three "low-cost" ISP are
much cheaper than only one "professionnal, SLA, etc" ISP and the
throughput is much more important.

Currently, there is no technical way to use these three ISP for
reliability (except may be SCTP, RFC 4960, for some uses), unless
there is a resident geek willing to play nice tricks with its FreeBSD
router.

But it is a technical problem (read: our responsability), not a
business issue. For most SOHO, having different "commodity" ISPs is
not different from going to different restaurants.

---

From: David Conrad <[email-masked]>
Date: Wed, 26 Sep 2007 10:26:19 +0200

On Sep 26, 2007, at 9:57 AM, Eliot Lear wrote:
> behaviors will differ at least in terms of technology adoption  
> lag.  A pizza parlor that takes its voice over IP is going to need  
> reliability because if it loses connectivity orders don't roll in.   
> Whether that is done by redundancy or by a single highly reliable  
> service will depend on the available services and their  
> reputations.  And I think the vote is still out on that.
>

People talk about the wildest things with IPv6: cellphones as routers  
connecting PANs, IPv6 addresses in every lightswitch, lightbulb, and  
carpet fiber, etc. and folk just nod their heads.

Yet people seem to think that mechanisms for connectivity will remain  
the same as in IPv4.

I think that in the long term, as people become more and more  
dependent on Internet-based technologies, it is likely that the  
demand for high reliability will be universal, not limited to  
businesses.  Multi-homing will be the rule, not the exception, even  
for home users.

A routing solution that does not take this into account is going to  
hurt.

Regards,
-drc

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From: "William Herrin" <[email-masked]>
Date: Wed, 26 Sep 2007 08:54:28 -0400

Brian,

I agree that with the technologies *deployed today*, SOHO users
generally do not have the sophistication to tease useful results out
of having multiple providers. Clearly folks like me are the exception
which is no doubt why so few people do it.

I strongly disagree with the assertion that few SOHO users would
multihome if the technology was within their grasp or the grasp of the
consultant they could hire for a couple hours to set it up. Quite the
contrary: in areas like mine, the economics favor it even before
considering reliability. Its much cheaper for me to double my
bandwidth by buying the base product from two providers than it is to
buy the higher speed product from just one of them.

Regards,
Bill

---

From: Robin Whittle <[email-masked]>
Date: Thu, 27 Sep 2007 22:05:03 +1000

In the absence of a new architecture (LISP/eFIT-APT/Ivip/TRRP), year
by year, X number (X will grow with each year) of end-user networks
will want and/or need stable IPv4 addresses, for the purposes of
multihoming and/or so they can choose ISPs without renumbering.
Without a new architecture, some proportion Y of those networks will
get PI address space, with each such network adding at least one
advertisement to the BGP system.

So without a new architecture, X*Y new advertisements will be added
to the global IPv4 BGP routing table - and each such network will
chew address space in multiples of 256 addresses.  (Of course this
would quickly run into limits due to shortage of fresh address
space, so to the extent that this shortage thwarts the reasonable
needs and desires of end-users - reducing Y - the impact on the
global routing table wouldn't be as bad.)

I don't know what X*Y will be for each year, but the number will
grow and soon be a few hundred thousand or more.

The question is:

  What proportion Z of these end-user networks could be run (in a
  way which reasonably meets the end-user's needs) with
  significantly less than 256 IP addresses?  (Say 128, 64, 32, 16,
  8, 4, 2 or even 1.)

My guess is that the answer would be "quite a large proportion".

This proportion Z will grow over time, since there will be more and
more general pressure to conserve IP addresses, and more development
and acceptance NAT etc. technologies to do this.

Any of the just mentioned new architectural proposals enable the
doling out of stable address space in increments of 128, 64 ... 1 -
for the purposes of multihoming and of choosing a new ISP without
renumbering.

X will grow forever.  Z will grow over time.

So X*Y*Z can be expected to grow to a large enough number within a
few years that I think it is fair to say that any of these new
architectures could and should make a significant contribution to
the more efficient use of IPv4 address space.  That won't resolve
the address shortage, but it will provide much-needed benefits.

Through no fault of its own, I can't see how IPv6 will be widely
adopted in the foreseeable future.  IPv4 was not designed to
facilitate migration to any other system.

I think the IPv4 address crunch will just lead to more and more
inventive ways of using address space efficiently.  Without a new
architecture, this will surely bloat the IPv4 global routing table
to double and beyond its current size in a few years.

No-one will be happy with an IPv6-only address until 99% or more of
other Internet users have an IPv6 address too.  There seems to be
little reason to get an IPv6 address at present, for most people,
and I can't see why this would change.

I think we are still going to be clamouring for IPv4 addresses in
ten or fifteen years time.  Maybe we will be stuck with it forever.
 I hope a new routing and addressing architecture can be implemented
around 2012.

 - Robin

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From: Iljitsch van Beijnum <[email-masked]>
Date: Thu, 27 Sep 2007 17:23:56 +0200

> multihoming and/or so they can choose ISPs without renumbering.

(which can be described as "serial multihoming")

>   significantly less than 256 IP addresses?  (Say 128, 64, 32, 16,

The only thing that absolutely, positively eats up addresses is  
servers that are reachable over SSL. For pretty much everything else  
you can have multiple logical servers share an IP address. With load  
balancers you can have multiple physical servers share an IP address.  
In my experience, there are significant numbers of organizations that  
have to be creative to get that coveted /24 block from RIPE (other  
RIRs have slightly different rules). That's today. Bandwidth is  
getting cheaper, address conservation is getting better, dependence  
on the internet keeps increasing.

> and I can't see why this would change.

What IPv6 brings to the table is a simpler network. We tend to forget  
this because we still assume that IPv4 will always be present, but if  
you compare an IPv6-only network to an IPv4 network, the IPv6 network  
is much easier to build and maintain. As IPv4 addresses become harder  
to get and IPv6 implementations become more mature, this difference  
will only become more pronounced.

Fortunately, the 99% issue is only applicable to a small subset of  
all applications. IPv6 deployment issues depend on the type of  
application: client/server or peer-to-peer, and one-to-few or one-to- 
many.

Client/server one-to-few would be email: you only talk to a very  
small number of mail servers. If those servers that you use are dual  
stack, you can run IPv6-only on your workstation and still read and  
write mail without trouble.

Client/server one-to-many is web: you talk to many different web  
servers. You can only be IPv6-only once ALL these servers are dual  
stack.

Peer-to-peer one-to-few is BitTorrent: you download pieces of files  
from different peers, but you don't really care from which peer. So  
as long as the tracker (coordinating server) and a reasonable subset  
of all peers is dual stack, you're in business.

Peer-to-peer one-to-many is VoIP: in theory, you can dial any number,  
so you can only run IPv6-only once your SIP server and all possible  
peers are dual stack.

Turns out you can easily move an application from the one-to-many to  
the one-to-few category by implementing proxies. So once your ISP (or  
IT department) has set up a dual stack HTTP/HTTPS proxy you can reach  
the web (in theory everything that uses TCP with the HTTPS proxy) and  
if your VoIP provider has an IPv6-capable gateway towards other  
networks, you can make calls over IPv6, too.

So in an environment where only a subset of all possible applications  
must be supported (i.e., an enterprise network) it's entirely  
possible to ditch IPv4 and proxy to the IPv4 world at the edge of the  
network.

>  I hope a new routing and addressing architecture can be implemented

I find it strange how people can make predictions that far in the  
future. Less than 1% of all people that are now running IPv4 were  
doing so 15 years ago. If you can go from 0 to 4 in 15 years, why not  
from 4 to 6 in as many or fewer years?