I am curious. Once we're nearing exhausting all IPv4 space will there ever come a time to ask/demand/force returning all these legacy /8 allocations? I think I understand the difficulty in that, but then running out of IPs is also a difficult issue. 
For some reason I sooner see all IPv4 space being exhausted than IPv6 being actually implemented globally.
Greetings,
Jeroen
Because it's no more than a delaying action. Even presuming
you get people to cooperate (and they really, have no incentive to
because they don't necessarily have any agreement covering the space
with the RIRs) rather than fire up their legal department....
  A couple of /8s doesn't last long enough to really make a dent
in the pain. You might buy yourself a few months at most.
  It might actually do more harm than good, by convincing people
that they can still get v4 space rather than worry about what they
are going to do in the future.
  --msa
Hmmm... it is 2pm on a Friday afternoon. I guess it's the appropriate time for this thread.
*grabs popcorn and sits back to watch the fun*
Must resist urge to bash v6... must start weekend... must turn off
computer for my own good.....
I am curious. Once we're nearing exhausting all IPv4 space will there ever
come a time to ask/demand/force returning all these legacy /8 allocations?
<snip>
Legacy vs RIR allocated/assigned space is not a proper distinction,
in-use vs not-in-use is a much better defining line for this debate.
Folks have been asked to return unused space for quite some time now,
see RFC 1917 - An Appeal to the Internet Community to Return Unused IP Networks (Prefixes) to the IANA.
Unless/until governments get involved, there is no one to demand or
force the return of any space. If that happens, we likely all lose.
While it is true that this is likely to be one of the less productive
windmill jousts.
I used to work for a holder of a /16 and strongly believe that they
(because of NAT-for-security and other reasons) actually using a small
fraction of the /16, and that that is being used is largely miss-managed.
Ob. declaration--I was fired from that organization for being too old.
I also just got a fresh box of popcorn. I will sit by and wait for Jeroen to do a business analysis and tell me the return on investment. (Assuming that he can find any legal grounds for demanding return of legacy /8 allocations.)
All of the analysis results I have seen mention figuratively beating oneself [..painfully..] with combat boots.
Running out of IP addresses is not a soon realized scenario for IPv6. If an organization runs out of IP addresses, the difficulty is with top management, not the network or address space.
I think this is a many-iterated discussion, also know by some as a "rathole".
Sigh... Guess you missed the last several go-arounds of
Running out of IPv4 will create some hardships. That cannot be avoided.
Even if we were to reclaim the supposed unused legacy /8s, we'd still
only extend the date of IPv4 runout by a few months.
The amount of effort required to reclaim those few IPv4 addresses would
vastly exceed the return on that effort. Far better for that effort to be
directed towards the addition of IPv6 capabilities to existing IPv4
deployments so as to minimize the impact of IPv4 exhaustion.
Owen
I am curious. Once we're nearing exhausting all IPv4 space will there ever
come a time to ask/demand/force returning all these legacy /8 allocations?<snip>
Legacy vs RIR allocated/assigned space is not a proper distinction,
in-use vs not-in-use is a much better defining line for this debate.
True, but...
Folks have been asked to return unused space for quite some time now,
see RFC 1917 - An Appeal to the Internet Community to Return Unused IP Networks (Prefixes) to the IANA.
Also true.
Unless/until governments get involved, there is no one to demand or
force the return of any space. If that happens, we likely all lose.
This is where Legacy vs. RIR becomes meaningful. Legacy holders have
no contractual obligation to return unused space. RIR recipients, on the
other hand, do.
Owen
Owen DeLong wrote:
The amount of effort required to reclaim those few IPv4 addresses would
vastly exceed the return on that effort. Far better for that effort to be
directed towards the addition of IPv6 capabilities to existing IPv4
deployments so as to minimize the impact of IPv4 exhaustion.
Maybe encourage people like Apple, Xerox, HP or Ford to migrate their operations completely to IPv6 and return their /8?
j
How are they going to completely migrate to v6 while
there is a demand for v4 space (specifically, THEIR v4 space.)?
  As long as the beast is getting fed, there will be customers
without v6, and they're not going to isolate themselves for the
commercial benefit of an unrelated third party.
  And even if they did, it's only going to buy you a few months.
  --msa
Cutler James R wrote:
I also just got a fresh box of popcorn. I will sit by and wait
I honestly am not trying to be a troll. It's just everytime I glance over the IANA IPv4 Address Space Registry I feel rather annoyed about all those /8s that were assigned back in the day without apparently realising we might run out.
It was explained to me that many companies with /8s use it for their internal network and migrating to 10/8 instead is a major pain.
Running out of IP addresses is not a soon realized scenario for IPv6. If an organization runs out of IP addresses, the difficulty is with top management, not the network or address space.
I also don't try to bash IPv6, I don't know enough about it yet to do that and I doubt I would. From a casual observer's point of view having that much more IP space to allocate can only be a good thing. But from the same observer's POV you can also reason it is taking very long to gain acceptance.
Regards,
Jeroen
Jeroen van Aart writes:
Cutler James R wrote:
I also just got a fresh box of popcorn. I will sit by and wait
I honestly am not trying to be a troll. It's just everytime I glance over the IANA IPv4 Address Space Registry I feel rather annoyed about all those /8s that were assigned back in the day without apparently realising we might run out.
It was explained to me that many companies with /8s use it for their internal network and migrating to 10/8 instead is a major pain.
You know, I've felt the same irritation before, but one thing I am wondering and perhaps some folks around here have been around long enough to know - what was the original thinking behind doing those /8s?
I understand that they were A classes and assigned to large companies, etc. but was it just not believed there would be more than 126(-ish) of these entities at the time? Or was it thought we would move on to larger address space before we did? Or was it that things were just more free-flowing back in the day? Why were A classes even created? RFC 791 at least doesn't seem to provide much insight as to the 'whys'.
- Andrew
Some legacy holders might, I imagine, be 'squatting' on that legacy space and
are getting ready to 'sell' some to the highest bidder, generating who knows
how much revenue, if their agreement allows them to do so.
A few of those same legacy holders might even want to impede IPv6 uptake to
make their /8 more valuable when the crunch comes.
Perhaps I'm too paranoid. But I'm sure I'm not the first person to think of
these possibilities (in my case, however, I have no legacy space, and wouldn't
go that route even if I did).
Jeroen van Aart wrote:
Cutler James R wrote:
I also just got a fresh box of popcorn. I will sit by and wait
I honestly am not trying to be a troll. It's just everytime I glance over the IANA IPv4 Address Space Registry I feel rather annoyed about all those /8s that were assigned back in the day without apparently realising we might run out.
Yes. We should all jump up and down and complain about the early adopters who were present at the time and helped develop (and fund the development of) the Internet into something that pays most of our paychecks today.
Or not.
And of course some of the folks who got /8s early on have turned them back. Others have merged into entities who use a whole lot of the space.
Matthew Kaufman
Jeroen van Aart writes:
Cutler James R wrote:
I also just got a fresh box of popcorn. I will sit by and wait
I honestly am not trying to be a troll. It's just everytime I glance over the IANA IPv4 Address Space Registry I feel rather annoyed about all those /8s that were assigned back in the day without apparently realising we might run out. It was explained to me that many companies with /8s use it for their internal network and migrating to 10/8 instead is a major pain.
You know, I've felt the same irritation before, but one thing I am wondering and perhaps some folks around here have been around long enough to know - what was the original thinking behind doing those /8s?
The original thinking was based on an environment where the Internet was expected to consist only of a few corporate entities providing services and products to research institutions and the government. There was no WWW, no browsers, and Windows couldn't even spell TCP/IP at the time.
The expectation was that those /8s would be subnetted into vast arrays of "Class C" sized chunks and that subnets within a given /8 all had to be the same size (this used to be necessary to keep RIP happy and every machine participating in RIP routing had to have an /etc/netmasks (or equivalent) table that tracked "THE" subnet mask for each natural prefix).
Sure, a /8 is a lot of addresses in today's world. However, back then, it was much like a /48 today. Just a way to give someone 65,500+ subnets (for any given X/8, then X.0/16, X.255/16, X.Y.0/24, X.Y.255/24 were unusable in these days).
I understand that they were A classes and assigned to large companies, etc. but was it just not believed there would be more than 126(-ish) of these entities at the time? Or was it thought we would move on to larger address space before we did? Or was it that things were just more free-flowing back in the day? Why were A classes even created? RFC 791 at least doesn't seem to provide much insight as to the 'whys'.
- Andrew
It was thought that we would not have nearly so many people connected to the internet. It was expected that most things connecting to the internet would be minicomputers and mainframes.
Owen
On the topic of IP4 exhaustion: 1/8, 2/8 and 5/8 have all been assigned in the
last 3 months yet I don't see them being allocated out to customers (users) yet.
Is this perhaps a bit of hoarding in advance of the complete depletion of /8's?
No, this is how the RIR process works. The RIRs request their next /8s and begin
the "cleaning" process on them several months prior to running out of their
previous allocations. This is done to try and make the allocations/assignments
from those blocks as immediately useful as possible to their customers.
I can assure you that RIRs are in the business of distributing IP resources within
the policy guidelines set by the community. They have no gain from holding or
hoarding them and are not in a position to do any such thing.
Owen
Doubt it. 1/8 is still being evaluated to determine just how usable
portions of it are, thanks to silly people of the world that decided
1.1.1.x and the like were 1918 space.
  As for the others, the RIR requests it when they are running low,
but certainly not exhausted, and as slow as people are to update their
bogon filters, it sounds like general good practice not to assign out of
a new /8 until pre-existing resources are exhausted.
  Can we put the tinfoil hats away and let this thread die now?
  --msa
Many large companies found that class A nets weren't very useful. Multiple levels of subnetting didn't exist, which meant that you couldn't assign a /16 to a location and a /24 to each piece of thick yellow cable within the location, for example.
AT&T got 12/8 moderately early. We realized we couldn't easily use it, and offered it back in exchange for the equivalent in class B space. Postel gave us the latter (135/8), but told us to keep 12/8 -- other people were discovering the same problem, so there was little demand for class A networks. (This was circa 1987, if memory serves, and possibly a year or two earlier.)
    --Steve Bellovin, http://www.cs.columbia.edu/~smb