Subject: RE: [Ietf] 240.0.0.0/4

From: Dean Anderson <[email-masked]>
Date: Thu, 22 Apr 2004 17:43:20 -0400 (EDT)

On Thu, 22 Apr 2004, Tony Hain wrote:

> You appear to overlook the case that H-D ratios apply to large complex
> enterprise networks just as they do to ISPs. Also, it is not necessary for
> all nodes to need public access. As soon as any do there is a need to avoid
> using any public prefixes on the internal network.

I agree completely. But even large complex, enterprise networks don't need
complete, fully routed connectivity.  As I said, I used to work for 
Hitachi, which is a very large enterprise.  This is why I doubt that 
anyone really needs more than the RFC1918 space.

> I understand what you wrote, but I think you are being overly simplistic. In
> some scenarios it is very likely that only 5% of the nodes need public
> access. This creates a situation where acquiring more public allocation is
> impossible due to current policy. At the same time there is no room to grow
> without guessing which /8's are going to be allocated last.

I suppose I am oversimplying. But I'm not sure I follow you. 

A large enterprise network has somewhat similar characteristics to a group
of companies operating over the public network. Only a small fraction of
the enterprise needs to get to every other part of the enterprise.  
Enterprises can use NATs internally the same way other companies use NATs
with the public network.

My point is that it takes a rather unusually extreme case to have an
enterprise that needs full connectivity internally, yet is so large that
it uses all of the available RFC1918 address space.  There are only a few
possible organizations worldwide that could be in this group.

There are some extreme cases of disconnection. For example, the internal
NSA networks are never going to be interconnected with the public network.
It would certainly be OK for the NSA to use address space other than
RFC1918 space.  However, I don't think the NSA is large enough to exhaust
the RFC1918 space. Indeed, I doubt that Hitachi is large enough to exhaust
the RFC1918 space.  

The main problem with RFC1918 space is inconvenient collisions. The same
space is used by 2 different divisions, that later need to interconnect.
It is not a lack of space--it is a lack of coordination. For companies
like Hitachi (not to pick on Hitachi), this would be just bad management.
They could have coordinated this. But in other cases, such as when
companies merge and find that they picked the same blocks, there is no way
they could have anticpated or coordinated the parts of RFC1918 space to
use.  More space doesn't solve this problem either (which I suspect is the
real motivator, though it was not stated as such)

		--Dean

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From: Dean Anderson <[email-masked]>
Date: Thu, 22 Apr 2004 17:43:20 -0400 (EDT)

--Dean

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From: "Tony Hain" <[email-masked]>
Date: Thu, 22 Apr 2004 19:45:26 -0700

> Enterprises can use NATs internally the same way other companies use NATs

You assume a specific application and traffic model when you claim that
enterprises can use NAT internally. This is not universally true.

> possible organizations worldwide that could be in this group.

Yes there are a small number, which is part of the reason they don't want to
stand up and be bashed by the IETF. They just want to use the technology as
it was intended to be used, and either need public space they will use for
non-public nodes, or additional private space.

> the RFC1918 space. Indeed, I doubt that Hitachi is large enough to exhaust

I don't know about either of your examples, but basing need on historical
use by traditional 'hosts' is ignoring the need to support growth and new
applications & appliances. 

> real motivator, though it was not stated as such)

Some organizations would no doubt be happy to have additional space to
reduce some of their pain caused by churn coupled with the scarcity of IPv4
addresses. That is not the motivator for the draft I submitted. There are
organizations that need more space now, and while they will be moving to
IPv6, they can't deploy all the pieces fast enough. 

Tony

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From: "Tony Hain" <[email-masked]>
Date: Thu, 22 Apr 2004 19:45:26 -0700

Tony