Hurricane Electric's IPv6 Tunnel Broker Forums

Tunnelbroker.net Specific Topics => Questions & Answers => Topic started by: awisskirchen on September 03, 2010, 03:47:44 AM

Title: routed /48
Post by: awisskirchen on September 03, 2010, 03:47:44 AM
Hello,

I like to test a routed /48-Network, but I can't allocate them.

This is the message that I see: Failed: Maxmimum # of 48s for this tserv allocated

Where is the problem ?

Thank you.

Regards
  Andreas
Title: Re: routed /48
Post by: cholzhauer on September 03, 2010, 05:12:48 AM
Quote
Maxmimum # of 48s for this tserv allocated

I would guess that the server can't allocate any more /48's. 

I think you should email ipv6@he.net and alert them to the problem you're having
Title: Re: routed /48
Post by: awisskirchen on September 03, 2010, 06:44:52 AM
mhh okay, but I tested with different server.
Title: Re: routed /48
Post by: broquea on September 03, 2010, 09:35:39 AM
That tunnel-server is out of available /48 allocations. We will be adding more in the future, however there is no ETA right now.  You can get a /48 for testing purposes by choosing a different tunnel server.

What did you want to "test" a /48 for? The only real difference between it and the routed /64 we already provide, is additional /64 subnets for different LAN segments. If you aren't using auto-configuration then you can use smaller blocks with DHCPv6 or even just static addressing.
Title: Re: routed /48
Post by: abelbeck on October 16, 2010, 07:12:53 PM
That tunnel-server is out of available /48 allocations. We will be adding more in the future, however there is no ETA right now.  You can get a /48 for testing purposes by choosing a different tunnel server.

I too would like to use autoconfig with multiple subnets, DHCPv6 is not supported with OS X yet.

Any update on the ETA for more /48's at Dallas? How about /56's is that a possibility?

Thank you for this excellent service.
Lonnie
Title: Re: routed /48
Post by: SimRett on January 10, 2011, 10:04:45 AM
I'd also happily take a /48 at Frankfurt...
Title: Re: routed /48
Post by: hisken on January 11, 2011, 07:16:24 AM
Funny to see how IPv6 address space can run out  ;D

But okay. Bit disappointing HE is running out of /48s. I have plenty of useful purposes for tunnel /48s, not just for experimental usage. For example: routing between two locations, and subnetting/dividing the upstream subnet I get from HE. We all know the RFCs describe a /64 as the absolute minimum at the customer premises (but often you can use smaller IP6 subnets-but RAs won't work with such subnets), and if a tunnel user needs to split it up for routing purposes it will get tricky if he only has a /64.

With lots of ISPs around that aren't yet IPv6-capable and a dissapointing amount of tunnel brokers (that crappy Freenet, HE and SixXS with their stupid admins) we need some good tunnelbrokers which can provide usable and complete IPv6 services to fill the gaps while ISPs aren't ready for IPv6 yet. And that includes /48s (or even better: /56s, a lot less waste of address space: a user really doesn't need 65535 /64s isn't it?).

IMHO, HE should take a look at implementing /56s instead of those large /48s. For example: make it possible to request a /56. And furthermore, you could add a form where users can apply for a /48 but only if they have a very good reason for it. @broquea: what about such an idea?
Title: Re: routed /48
Post by: SimRett on January 11, 2011, 09:38:13 AM
Agreed, /56 would be fine; heck, even /60 should suffice for me. In my specific case I have two subnets to serve with ~10 users and would like to use RAs, since some OSes don't support DHCPv6 yet.
Title: Re: routed /48
Post by: marcusw on January 22, 2011, 10:03:28 PM
If you don't mind me asking, why would one even want more than one /64 subnet on a single LAN? Don't subnets become irrelevant now that there is global routing for everything? Wouldn't having subnets increase the number of hops and therefore latency between nodes?

Pardon my ignorance.
Title: Re: routed /48
Post by: jimb on January 22, 2011, 10:14:05 PM
No.  Subnetting is still required.

You need the /48 when you need more than one LAN, otherwise a /64 suffices.

There's nothing magic about IPv6 which makes sizing LANs much different than under IPv4.  Just easier since there are pretty much fixed LAN sizes now and you'll never have to worry about running out of host numbers etc or networks.  However, you still don't want more than so many nodes on a single LAN for the same reasons you don't under IPv4.

I have started to see another trend towards "flattening" networks again ... similar to one I saw back in the 90s.  But as I said, having too many nodes on a single LAN has similar pitfalls under v6 as it did under v4.  Too large of a "multicast domain" is just as bad as too large of a broadcast domain.

Also, as for /48 vs. /56 etc, etc, this ground has been covered many times.  Basically, /48s are what the IANA recommends to assign to end users with more than one LAN, or businesses, per site.  It might seem wasteful, but the IPv6 space is so huge that it's not a concern.  Having large assignments like that also reduces the size of routing tables and makes routing faster/less expensive (less expensive TCAM needed, etc).
Title: Re: routed /48
Post by: hisken on January 23, 2011, 04:38:04 AM
Also, as for /48 vs. /56 etc, etc, this ground has been covered many times.  Basically, /48s are what the IANA recommends to assign to end users with more than one LAN, or businesses, per site.  It might seem wasteful, but the IPv6 space is so huge that it's not a concern.  Having large assignments like that also reduces the size of routing tables and makes routing faster/less expensive (less expensive TCAM needed, etc).

Interesting matter. But is there really any performance hit when a ISP for example has like 30.000 /48s versus 30.000 /56s in their BGP? Obviously the number of subnets allocated from the /32 would be the same in both situations. Correct me if I'm wrong. Even when very big ISPs would be using /56s they would only need one /32 in most situations. Of course, the routing table of that /32 would be a lot heavier compared to multiple /32s with /48s in it. Is that the kind of performance hit you are referring to?
Title: Re: routed /48
Post by: marcusw on January 23, 2011, 05:54:32 AM
No.  Subnetting is still required.

You need the /48 when you need more than one LAN, otherwise a /64 suffices.

There's nothing magic about IPv6 which makes sizing LANs much different than under IPv4.  Just easier since there are pretty much fixed LAN sizes now and you'll never have to worry about running out of host numbers etc or networks.  However, you still don't want more than so many nodes on a single LAN for the same reasons you don't under IPv4.

So I would want a /48 if I had, for example, more than about 500 hosts on my LAN? Or are there other reasons? It can't be organisation, since things are the same connectivity wise whether there's a router in the middle or not. Thanks for explaining this to me.
Title: Re: routed /48
Post by: hisken on January 23, 2011, 07:26:45 AM
Quote
So I would want a /48 if I had, for example, more than about 500 hosts on my LAN? Or are there other reasons? It can't be organisation, since things are the same connectivity wise whether there's a router in the middle or not. Thanks for explaining this to me.
Yeah, that could be one reason though those 500 hosts can obviously perfectly fit in a /64.

You'd want a /48 or /56 for subnetting things up. For example like when you are setting up a VPN server at home, you could use a second /64 for it and make it routable. If you didn't have a /48 or /56 in that case at your home, your only options would be splitting a /64 (not recommended since minimum "official" size is a /64) or a Layer-2 VPN bridge (much more overhead, also not recommended).
Title: Re: routed /48
Post by: jimb on January 23, 2011, 04:14:31 PM
Heh yeh I thought about the routing table size thing to after I posted that, and it probably wouldn't make a big difference in routing table size in the end.
Title: Re: routed /48
Post by: xezlec on February 15, 2011, 10:10:48 AM
Also, as for /48 vs. /56 etc, etc, this ground has been covered many times.  Basically, /48s are what the IANA recommends to assign to end users with more than one LAN, or businesses, per site.  It might seem wasteful, but the IPv6 space is so huge that it's not a concern.

It has been covered many times, and the obviously wrong answer reached and stubbornly defended every time.  A /56 is ludicrous overkill.  A /48 is just throwing bits away for no reason at all.  A /48 for every user (which, in virtually every case, will be populated by a single device) means that essentially all of the addressing of the internet must be crammed into 48 bits.  That's only slightly longer than an IPv4 address.

A middle-ground projection of future world population is 15 billion.  Dividing by the current population of internet-enabled users, we see that growth by a factor of 32 (5 bits) is reasonable to expect.  Allocating larger prefixes higher up in the network hierarchy genuinely might help with routing (though I don't see how allocating extra bits at the level of a customer's home network does that), so we can expect to lose, very conservatively, another factor of 64 (6 bits) for that.  Internet growth is exponential even in regions where most of the population already has internet access (due to the proliferation of new ways and places that an individual accesses the internet throughout his day, i.e. all of the new mobile devices now coming on the market).  We can expect at least a factor of 16 (4 bits) from that.  There's a factor of 8 taken out by the IANA because of the reservation of most of the /3's.  Putting it all together:

+ 32 bits currently occupied by the world
+ 5 bits population growth and internet uptake
+ 6 bits elbow room for routing
+ 4 bits device proliferation
+ 3 bits reserved by IANA
----
50 bits needed

And yet we're giving each residential home user a /48?  And you don't think it's a concern?  And this only takes into account likely, known scenarios.  What about the unknown unknowns?  Shouldn't we plan for that?  What if we want to assign IP address space to other astronomical bodies or something (sure, there's lag, but that's not a huge problem for streaming multimedia).

Quote
Having large assignments like that also reduces the size of routing tables and makes routing faster/less expensive (less expensive TCAM needed, etc).

Why does allocating a bigger prefix make routing more efficient even when the extra bits will obviously not be used by the customer?  Name a case where an ordinary user will need thousands of subnets.  Even a futuristic sci-fi case.  I can't think of one.

Quote
So I would want a /48 if I had, for example, more than about 500 hosts on my LAN?

Nope.  One subnet is always a /64.  You would need a /48 if you had about 500 subnets, each with multiple computers and a router of its own.  If you only have a hundred or so subnets, not thousands, a /56 is fine.  In reality, no one has more than one subnet at home, so a /64 is fine.  If some weirdo really wants multiple subnets at home, they should request special treatment from their provider and expect to pay more.  /56 by default is silly and /48 is indefensible.

In the year 3000, there will not be one single IP address in the world with any nonzero bits between the 48th and 56th bit (I invite you to try and argue otherwise), but the address space above that will be crammed and crowded as all heck.  There's something wrong with that.
Title: Re: routed /48
Post by: xezlec on February 15, 2011, 10:17:49 AM
Oh, and another thing, putting extra space at the top means you can always allocate it downward to people as needed, but allocating it at the bottom means you can't easily get it back if needed.  So it's dumb that we're putting all the padding at the bottom of the address and none at the top (especially since the top is where we're seeing all the growth in the industry).
Title: Re: routed /48
Post by: jgeorge on February 15, 2011, 11:35:10 AM
Basically, /48s are what the IANA recommends to assign to end users with more than one LAN, or businesses, per site.

And yet we're giving each residential home user a /48?

Nope, nobody ever said that. As far as address allocations go, a "residential home user" is not the end consumer of IP address space. Their ISP is the end user of that address allocation.

Joe
Title: Re: routed /48
Post by: xezlec on February 15, 2011, 11:40:51 AM
Basically, /48s are what the IANA recommends to assign to end users with more than one LAN, or businesses, per site.

And yet we're giving each residential home user a /48?

Nope, nobody ever said that. As far as address allocations go, a "residential home user" is not the end consumer of IP address space. Their ISP is the end user of that address allocation.

Joe

It depends how you read the recommendation in the RFC.  The way I read it, an ISP gets a /32 and a /48 is only for a single office or building.  Hurricane Electric offers /48 tunnels to pretty much anyone who wants one, right?
Title: Re: routed /48
Post by: cholzhauer on February 15, 2011, 11:43:01 AM
Quote
The way I read it, an ISP gets a /32 and a /48 is only for a single office or building.  Hurricane Electric offers /48 tunnels to pretty much anyone who wants one, right?

Any one can have a /48 that wants one.  Technically speaking, isn't a house a building?  With that logic, they get a /48 too
Title: Re: routed /48
Post by: jimb on February 15, 2011, 02:57:36 PM
A /48 per customer isn't set in stone, but there is enough IPv6 space for the foreseeable future.  I could see ISPs giving out /56s or even /60s to end customers.  Or just individual /64s as needed.  It's really up to them, there address and routing plan, etc.

But /48 per site wont "break the bank" for the foreseeable future.  Considering only the current slice of the IPv6 space in use today, 2000::/3, there are ~536 million /32s.  If you gave ISPs, super large datacenters, govt agencies, etc,  1000 /32s each, there'd be ~536,000 of them to give out.  Think about that.  You'd have to give out ~536,000 1000 /32 netspace chunks of just the current in-use /3 to exhaust the entire /3.  Are there even that many ISPs, dataceneters, govt agencies in the world?  And each would get 1000 /32s, which have enough space for ~65,536,000 /48s to give to customers.  And oh yeah, after that there's seven more /3s to use.

By the year 3000, we won't be using IPv6 anymore, since other factors (the "unknown unknowns" you speak of) will have likely made IPv6 obsolete.  In the year 3000 the world won't even be recognizable to us, even if the human race is still around.  :P  That's 1000 years.  Think about the world we have now, vs. the world in the year 1011.  
Title: Re: routed /48
Post by: xezlec on February 15, 2011, 05:18:29 PM
A /48 per customer isn't set in stone, but there is enough IPv6 space for the foreseeable future.  I could see ISPs giving out /56s or even /60s to end customers.  Or just individual /64s as needed.  It's really up to them, there address and routing plan, etc.

So could I.  That's why I'm saying they should do that.  This thread started because Hurricane Electric doesn't do that and one server ran out of /48s.

Quote
But /48 per site wont "break the bank" for the foreseeable future.

I was trying to show numerically that it may get tight, if you look at my numbers.  And it's just unnecessary.  A little common sense now will prevent even the possibility of that, without any negative consequences.  There are no ill effects from allocating /56s instead of /48s.

Quote
Considering only the current slice of the IPv6 space in use today, 2000::/3, there are ~536 million /32s.  If you gave ISPs, super large datacenters, govt agencies, etc,  1000 /32s each, there'd be ~536,000 of them to give out.  Think about that.  You'd have to give out ~536,000 1000 /32 netspace chunks of just the current in-use /3 to exhaust the entire /3.  Are there even that many ISPs, dataceneters, govt agencies in the world?  And each would get 1000 /32s, which have enough space for ~65,536,000 /48s to give to customers.  And oh yeah, after that there's seven more /3s to use.

And you'd have an even more fragmented network than we have today.  You have to allow some slack space to group things together.  You can't just assume 100% utilization.  That's crazy.  IPv4 only gets about 14%, and a longer address space will be much worse.  And no, as a matter of fact, 500k datacenters in the world would only be about one for every 30,000 people, in a world with 15 billion people.  That obviously wouldn't be enough (to say nothing of ISPs and government agencies).  If you'll just look at the numbers I quoted, or take a look at the exponential rate of internet increase around the world, you'll see that this is not an unrealistic concern.  And it's so easy to fix!

Quote
By the year 3000, we won't be using IPv6 anymore, since other factors (the "unknown unknowns" you speak of) will have likely made IPv6 obsolete.

I was trying to head off any such speculation.  My claim is that the addresses will run out much sooner than that.  The year 3000 thing was to point out that the /48 policy doesn't have any obvious purpose even if we do hopelessly try to think that far ahead.

Nothing you mentioned presents a good reason to allocate each of us a /48.  You're just trying to say it doesn't hurt anything.  But then why do it if there's no reason to?
Title: Re: routed /48
Post by: cholzhauer on February 15, 2011, 05:39:28 PM
i have to agree with jim.  we need to move away from ipv4 thinking in the way we allocate ip addresses.
Title: Re: routed /48
Post by: broquea on February 15, 2011, 06:39:28 PM
We didn't run out of /48s. We set a maximum number per tunnel-server, the more popular ones got larger allocations. We're looking at a different way of allocating master blocks to the tservs so more /48s can be made available, however there is no lack of available /48s out of our /32.
Title: Re: routed /48
Post by: xezlec on February 16, 2011, 12:49:31 PM
i have to agree with jim.  we need to move away from ipv4 thinking in the way we allocate ip addresses.

I'm not sure what you mean by "ipv4 thinking" but I would very much like to know why we need to move away from allocating addresses in a responsible, common-sense way.  Please explain the benefit of allocating /48s instead of /56s.

We didn't run out of /48s. We set a maximum number per tunnel-server, the more popular ones got larger allocations. We're looking at a different way of allocating master blocks to the tservs so more /48s can be made available, however there is no lack of available /48s out of our /32.

I didn't mean to suggest that you ran out entirely.  But the fact that you need to look for a new way of allocating them to the servers seems unnecessary.  If you just hand out /56s, this problem won't exist, and there is no downside at all.  Isn't that easier than looking at a different way of allocating master blocks?  And it's much more responsible in the long run.  I have shown numerically that the current practice is ultimately unsustainable.
Title: Re: routed /48
Post by: broquea on February 16, 2011, 01:26:53 PM
Policy is /48s for those that need multiple subnets.
Title: Re: routed /48
Post by: PigLover on February 17, 2011, 03:06:19 AM
Zezlec, when you begin with a flawed argument you are likely to end up with wrong conclusions, to wit:

...A /48 for every user (which, in virtually every case, will be populated by a single device) means that essentially all of the addressing of the internet must be crammed into 48 bits.  That's only slightly longer than an IPv4 address...

A /48 is not "just slightly larger" than the current internet.  It is 16 bits larger - >65,000 times larger.  I don't know about you, but for me, that is not "slightly".  That's enough to allocate the entire internet address space separately to every country - no - every province of every country - and still have about 60,000 times more address space leftover than the total we have today.  Your concept of scale is completely off.

Furthermore, you are comparing network addressing in v6 to host addressing in v4.  Since the smallest non-subnetted network in v4 is a class C, a /48 is actually 24 bits larger, making the available space a few million times larger than what we had even with what you argue is 'inefficient' allocation.

/48s for every multi-LAN user are fine.
Title: Re: routed /48
Post by: jschweitzer on February 17, 2011, 06:23:16 AM
xezlec - after reading this entire thread, my opinion is that you are trying to "realize" or "quanitfy" the IPv6 address space in a way that you can understand.  ive seen many people try to do this.

the address space of IPv4 is easy for the human brain to understand - 4.2x billion addresses.  theyre all allocated now.  But the IPv6 address space is simply not quantifiable by the human brain.  no one truely has any idea just how big 340 undecillion addresses is.

i think everyone agrees that addresses should be allocated in a thoughtful manner, but you dont fully realize just how many addresses there really are.  fighting over /48s or /56s just doesnt matter.  btw, where did you ever get the /56 idea?  ive never once seen anyone suggest a /56 before...

edit: ok, i just learned about /56s  ;)
Title: Re: routed /48
Post by: cholzhauer on February 17, 2011, 06:27:01 AM
GoGo6 offers a /56 with their services.  IIRC, you get 256 /64's instead of 64k worth of /64s in a /48
Title: Re: routed /48
Post by: jimb on February 17, 2011, 02:59:17 PM
GoGo6 offers a /56 with their services.  IIRC, you get 256 /64's instead of 64k worth of /64s in a /48
IIRC?

NUM_SUBNETS = 2^(LAN_PREFIX_LENGTH - PREFIX_LENGTH)
2^(64 - 56)  = 256
2^(64 - 48) = 65,536

 ;D
Title: Re: routed /48
Post by: cholzhauer on February 17, 2011, 07:18:06 PM
If I recall correctly

Thanks for backing my answer up with proof :)
Title: Re: routed /48
Post by: torero on February 18, 2011, 02:25:44 AM
Hello all,

For these topics I use http://www.bitcricket.com/ip-subnet-calculator.html (Only for Windows & MacOS X).

Salu2
Alo
Title: Re: routed /48
Post by: jimb on February 18, 2011, 02:33:59 AM
Hello all,

For these topics I use http://www.bitcricket.com/ip-subnet-calculator.html (Only for Windows & MacOS X).

Salu2
Alo
For *nix type operating systems, sipcalc works well (http://www.routemeister.net/projects/sipcalc/ (http://www.routemeister.net/projects/sipcalc/)).  It also compiles and works under Cygwin (although I can't get GCC to compile it under cygwin running on win7 64 :( ).  Does IPv4 and IPv6 of course.

I have one on my android phone which is pretty decent too, called IP Calculator+, although it doesn't let you do things liek split a prefix into subnets, etc.
Title: Re: routed /48
Post by: xezlec on February 18, 2011, 01:14:28 PM
A /48 is not "just slightly larger" than the current internet.  It is 16 bits larger - >65,000 times larger.  I don't know about you, but for me, that is not "slightly".  That's enough to allocate the entire internet address space separately to every country - no - every province of every country - and still have about 60,000 times more address space leftover than the total we have today.  Your concept of scale is completely off.

I don't care to quibble over language, but I've shown that the factor of 65536 is not necessarily large enough to work in a realistic case.  No "concept of scale" was required in this reasoning.  I used mathematics and what I think are realistic estimates of various effects.  If you have a problem with any of those estimates, say so.  If you think I made a mistake in the math, show where.  Otherwise, why are we still arguing?

These things you say about countries would be just fine, if you use the IANA reserved bits for unicast addressing (I'm not sure this will or should necessarily happen) and assume perfect allocation at the level of countries and provinces (laughable).  But even then, you wouldn't have enough addresses in the end.  One internet for each province sounds like a lot until you look at population growth and the growth of the number of people on the internet.  Only a tiny percentage of the world's people are online now.  That's why I factored the assumption that everyone will have internet access eventually into my math.  Once you factor in that, and the continual growth in the number of internet-enabled devices a typical person uses, you'll see exactly what I showed: things get tight, especially if something unexpected comes up.  Did you look at my numbers?

Quote
Furthermore, you are comparing network addressing in v6 to host addressing in v4.  Since the smallest non-subnetted network in v4 is a class C, a /48 is actually 24 bits larger, making the available space a few million times larger than what we had even with what you argue is 'inefficient' allocation.

Nope.  Currently, most residences have ONE address.  If they have a subnet, they use NAT, not a class C.  The IPv6 policy is to assign a /48 to each of these people, so each ONE IPv4 address is being replaced by a /48.  The situation may be different for businesses, but I'm not sure, and I don't know how many businesses are really just small entities with one or two computers.

Quote
/48s for every multi-LAN user are fine.

So are /56s for (practically) every multi-LAN user.  So why allocate /48s?  No reason at all?  Milk is cheap, so why not just pour a gallon down the drain?  So far, every single person on this thread seems to be in full agreement that /48s offer no advantage whatsoever over /56s for all but the very largest businesses.  So why allocate them, and why argue for them, if they have no benefit whatsoever?  Isn't it irrational to argue stubbornly for a policy choice that you believe will have no effect at all?  I don't understand this.

xezlec - after reading this entire thread, my opinion is that you are trying to "realize" or "quanitfy" the IPv6 address space in a way that you can understand.  ive seen many people try to do this.

the address space of IPv4 is easy for the human brain to understand - 4.2x billion addresses.  theyre all allocated now.  But the IPv6 address space is simply not quantifiable by the human brain.  no one truely has any idea just how big 340 undecillion addresses is.

Uh... it is very easy to quantify the IPv6 address space.  It is, in total, 2^128 addresses.  They are then broken down and allocated in a specific way.  And yes, everyone with a basic understanding of arithmetic knows precisely how big 2^128 is.  I know how to add numbers together and I know they don't add up to a small enough value to make this a good idea.  I showed this.  Why does everyone here keep insisting on talking about things using hand-waving and intuition?  Why not just do the math and see for yourself?

Also, you misunderstand a few things if you think you can really put 2^128 computers on IPv6.  Each subnet gets a /64.  That means, no matter how big a number 2^128 is, there can only be 2^64 subnets.  The only way you can have 2^128 computers is if every subnet has 2^64 computers on it.  The maximum possible number of computers on a subnet is much, much smaller than this, and the majority of subnets will have only 1 computer.  Similar reasoning applies for /48s.  Once you've assigned a /48, all the numbers under it are allocated.  They're gone.  It doesn't matter how many computers that home user has, all of those addresses are gone now and can never be used again (barring renumbering, which won't likely happen).  Since most of these users only have 1 computer, that means you only get 2^48 computers, plus a few.