Re: I-D ACTION:draft-wilson-class-e-00.txt

At 07:38 AM 8/9/2007, Marshall Eubanks wrote:


> On Aug 8, 2007, at 4:22 PM, David Conrad wrote:
>
> > Hi,
> >
> > On Aug 8, 2007, at 10:18 AM, Hallam-Baker, Phillip wrote:
> > > Which widespread IPv4 stacks?
> > I think it might be easier to identify stacks that don't disallow
> > 240/4.  I don't actually know of any widespread ones.
> I had a specific idea for 240 and asked around and didn't find any
> either. So, this means a year or two to
> develop and deploy at best, and probably a fork-lift upgrade at that,
> which does not seem that attractive.
>
> If someone came out with a specific idea backed by hardware, though,
> is there a reason not to let
> them go forward ?
If the IETF published an RFC that reassigned 240/4 to private address 
space usage today, it would likely be possible for enterprises to use 
it within a reasonably short period, perhaps a year or so, depending 
on how many vendors they work with, and their ability to assert pressure.
Let's look at the reality of software stacks in the present time. 
Micorosoft updates desktops and servers weekly or more often, and 
people are fearful enough of security matters that they do apply 
them. Linux vendors similarly release patches quite often. Router 
vendors seem to have new software for one fix or another daily.
If enterprises started working toward a deployment of pieces of 
240/4, vendors would make it possible.
A few of us looked at the Class-E issue some years ago, and thought 
it was worthwhile at that time to reclassify the space. Everyone 
understood it would take some time before the space was widely usable.
If there's to be any use of the space, ever, a scenario that would 
get us to usability might be:
- Reclassify Class-E space as usable address space

- Enable a few pieces of 240/4 as private address space use. Let 
people start using that.
- Enterprises, if there's interest will push vendors to make changes to stacks

- In a few years, evaluate whether the space is viable for public 
assignment by ARIN, et. al.
Even if the initial use of such space is limited to a few platforms 
and routers, it may be sufficiently useful to enterprises to use in 
private interconnects between companies, an area where significant 
difficulties are encountered today due to address re-use.
There will of course be a chorus of responses that if changes are 
required anyway, folks should just migrate to IPv6. The 
counter-argument I'd make is simple: the changes required in IP 
stacks to enable Class-E as valid addressing is minimal, resulting in 
little new code, and thus little risk from untested code. Initially 
allowing blocks from this space as additional RFC1918-style space 
would provide a playground where enterprises, users and vendors could 
test their wares, without risk to the public Internet.
For enterprises, the migration to IPv6 will be slow. The protocol 
stacks from all of the vendors are largely untested. I don't mean 
they haven't run code coverage, had QA teams and even 
interoperability testing. I mean there is limited experience with 
wide scale networks, high traffic volumes, exposure to denial of 
service and probing attacks. There will be vulnerabilites, just as 
there is with any code that's relatively new.
As I believed several years ago, reclassifying 240/4 is worthwhile. 
Leveraging the need of enterprises for additional, sanctioned, 
private IPv4 space for interconnects may result in widescale 
implementation. Or it might not. The point is, it would be relatively 
simple to find out, and would not be overly distracting to the IETF 
or to efforts to migrate to IPv6 .


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