Re: Private use of non-RFC1918 IP space (IPv6-MW)
--On onsdag, onsdag 4 feb 2009 19.02.56 -0500 "Patrick W. Gilmore" wrote: > Second, where did you get 4 users per /64? Are you planning to hand each > cable modem a /64? Telia got their /20 based on calculations where they give every customer a /48. Every apartment in every highrise gets 2^16 networks. I think that /56 or /52 is a more appropriate allocation per broadband subscriber. -- Måns NilssonM A C H I N A ... he dominates the DECADENT SUBWAY SCENE. pgp9epLSXt9oD.pgp Description: PGP signature
Re: Private use of non-RFC1918 IP space (IPv6-MW)
On 5/02/2009, at 3:09 PM, Matthew Moyle-Croft wrote: TJ wrote: No, we should hand each home a /56 (or perhaps a /48, for the purists out there) - allowing for multiple segments (aka subnet, aka links, etc.). If there are, say, 250-500 million broadband services in the world (probably more) then, if every ISP followed best practise for IPv6 address allocation, (sparse, bits for infrastructure, whatever etc) then what percentage of the space do we have left if we hand out /56 or /48s?). Taking into account the space already carved off for link local, private addressing, US Military etc. Has anyone done some analysis of what this might look like? Especially with growth etc. My addressing plan works like this: ISP gets /32, 2001:db8::/32 - 2001:db8:0::/48 = ISP use -- 2001:db8:0:0::/64 = infrastructure --- 2001:db8:0:0:0:0:0::/112 = loopbacks ( 65536 ) --- 2001:db8:0:0:1:0:0::/112 through 2001:db8:::::0/112 = / 112 link nets between ISP routers ( 281474976710656 ) -- 2001:db8:0::/64 through 2001:db8:0:::/64 = ISP networks, ie. servers, etc. - 2001:db8:1::/64 through 2001:db8::::/64 = customer networks. Assuming the above, we have 65535 /48s available to customers, or 16,711,680 /56s. The "ISP use" /48 burns 256 /56s, or potential customers. So, like burning a /24 for the entire ISP operation. So, if you have more than 65K business customers, get more than a /32. If you have more than 16M residential or small business customers, get more than /32. The above plan puts the addresses you type lots (loopbacks, link nets) on the shortest addresses you have - you can use the zero compression :: thing. These are also the addresses that cause the most trouble if fat fingered, so shorter addresses leave less room for error. In addition, the entire first /64 (loopbacks, link nets) should never really receive packets from outside the network. Drop in an ACL. Modification to the above plan is to use /64s for link nets between ISP routers, if you are worried about compatibility issues. You now have a trade off between 65k ISP server networks, and 65k link nets. Let's say 32k for each. -- Nathan Ward
RE: Private use of non-RFC1918 IP space (IPv6-MW)
>Has anyone done some analysis of what this might look like? Especially with growth etc. Sure, probably lots of people lots of times. Off the top of my head, using some current/common allocations sizes: Current "Global Unicast" space --> 2000::/3 An "average" RIR --> /12 an "average" ISP --> /32 an average enterprise --> /48 an average home user --> /56 So, "the current IPv6 world" (2000::/3) can support 512 standard RIR sized allocations. Each standard RIR can support 1M standard ISPs. Each standard ISP can support 64K enterprises or 16M standard home-users, or some combination thereof. So -How much do we want held in reserve? How "flexibly" (ref RFC3531) are we allocating our addresses? How many total (enterprise | home) clients do we want to support? Off the cuff, let's say we use left-most (sparse) allocation and only hit 50% efficiency (keeping the right-most bit totally in reserve!) ... If I am an ISP, and I have 300M home users (/56s) I just need a /26, and that actually gives me a lot of room for more clients (like 200M more). So - what was the problem again? Let's make it even more interesting - let's say I am an ISP, I am allocating /48s, and I need to support - say - 6B assignments for every person in the world + 2B for every organization in the world (#s chosen arbitrarily, feel free to add another bit if it makes you feel better). Bearing in mind that this means every single person and organization has 64k subnets, each of which contains "as many hosts as is appropriate", and all of these are globally routable ... I "just" need a /15 to cover this absolute worst case. Heck, let's make it /14 for good measure. So now each standard RIR can "only" support 4 of this size service provider, but we still have 512 RIR sized allocations. If the individuals got /56s instead these numbers getting even bigger ... So - what was the problem again? Oh, and this is just from the 2000::/3 range ... next up, 4000::/3 ... 6000::/3, 8000::/3, a000::/3, c000::/3. And if we feel like we burned through 2000::/3 too fast at some point in the future, maybe we revisit the rules around the time we start thinking about allocating from 4000::/3? (Or "skip one", and star the new rules with 6000::/3 ... I am not picky). Note, I am _NOT_ saying we should be careless or cavalier about address allocation, just saying we don't live in a constrained situation. And if there is a choice to be made between scalability/flexibility/summarization'ability (is that a word?) and strict efficiency ... the efficiency loses. /TJ PS - Yes, 4.3B seemed really big at one point ... but seriously, do the above numbers not _really_ sound big enough?
Re: Private use of non-RFC1918 IP space (IPv6-MW)
TJ wrote: No, we should hand each home a /56 (or perhaps a /48, for the purists out there) - allowing for multiple segments (aka subnet, aka links, etc.). If there are, say, 250-500 million broadband services in the world (probably more) then, if every ISP followed best practise for IPv6 address allocation, (sparse, bits for infrastructure, whatever etc) then what percentage of the space do we have left if we hand out /56 or /48s?). Taking into account the space already carved off for link local, private addressing, US Military etc. Has anyone done some analysis of what this might look like? Especially with growth etc. MMC -- Matthew Moyle-Croft - Internode/Agile - Networks Level 4, 150 Grenfell Street, Adelaide, SA 5000 Australia Email: m...@internode.com.au Web: http://www.on.net Direct: +61-8-8228-2909 Mobile: +61-419-900-366 Reception: +61-8-8228-2999 Fax: +61-8-8235-6909
Re: Private use of non-RFC1918 IP space (IPv6-MW)
TJ wrote: >> Some devices will refuse to work if you subnet smaller than a /64. (Yes, >> poorly designed, etc.) > > Actually, no - not poorly designed. The spec says it must be a /64 > (excluding those starting with 000 binary) so that is what devices > (rightfully) expect. Ref: http://tools.ietf.org/html/rfc4291#section-2.5.1 > I was just trying to head off the flood of "poorly designed" comments last time I said such a thing on a different list. ;) I find /64 convenient because it ends on a nice boundary out of my /48 and for my purposes it's more than enough space. The only annoyance I've come across was my Cisco devices will only accept an EUI-64 address as a host address in an ACL. Not a big deal though. ~Seth
RE: Private use of non-RFC1918 IP space (IPv6-MW)
>Some devices will refuse to work if you subnet smaller than a /64. (Yes, >poorly designed, etc.) Actually, no - not poorly designed. The spec says it must be a /64 (excluding those starting with 000 binary) so that is what devices (rightfully) expect. Ref: http://tools.ietf.org/html/rfc4291#section-2.5.1 /TJ
RE: Private use of non-RFC1918 IP space (IPv6-MW)
>> On Mon, Feb 2, 2009 at 9:35 PM, Patrick W. Gilmore >> wrote: >> >>> Except the RIRs won't give you another /48 when you have only used >>> one trillion IP addresses. >> >> Of course they will! A /48 is only the equivalent of 65536 "networks" >> (each network being a /64). Presuming that ISPs allocate /64 networks >> to each connected subscriber, then a /48 is only 65k subscribers, or >> say around a maximum of 200k IP addresses in use at any one time >> (presuming no NAT and an average of 3-4 IP-based devices per >> subscriber) >> >> IPv4-style utilization ratios do make some sense under IPv6, but not >> at the address level - only at the network level. > >First, it was (mostly) a joke. > >Second, where did you get 4 users per /64? Are you planning to hand each >cable modem a /64? No, we should hand each home a /56 (or perhaps a /48, for the purists out there) - allowing for multiple segments (aka subnet, aka links, etc.). Note - the actual number of hosts is irrelevant; the 64 bits on the host side of the address are not meant to encourage 18BB hosts/segment. Oh, and utilization should be based on /56s anyway. /TJ
Re: Private use of non-RFC1918 IP space (IPv6-MW)
On Wed, 4 Feb 2009 15:56:44 -0800, Scott Howard wrote: > On Mon, Feb 2, 2009 at 9:30 PM, > Anthony Roberts wrote: > >> It has been my experience that when you give someone a huge address space >> to play with (eg 10/8), they start doing things like using bits in the >> address as flags for things. Suddenly you find yourself using a prefix >> that should enough for a decent sized country in a half-rack. > > Which is, of course, a core design philosophy for IPv6. Stateless > autoconfig > relies on the fact that each network will be allocated 2^64 address. I'm actually pretty happy about /64's, they take away all the hand-wringing over how big a network should be, and they make manually configured server addresses easier to remember through the use of big regions of 0s. I was thinking more about wasting prefix bits. -Anthony
RE: Private use of non-RFC1918 IP space (IPv6-MW)
> > IPv4-style utilization ratios do make some sense under IPv6, but not > > at the > > address level - only at the network level. > > First, it was (mostly) a joke. > > Second, where did you get 4 users per /64? Are you planning to hand > each cable modem a /64? > At the least. Some would say a /56 is more appropriate. So, one /64 for your desktop and one /64 for your open wireless. :-) Mike PGP.sig Description: PGP signature
Re: Private use of non-RFC1918 IP space (IPv6-MW)
Patrick W. Gilmore wrote: > On Feb 4, 2009, at 6:56 PM, Scott Howard wrote: >> On Mon, Feb 2, 2009 at 9:35 PM, Patrick W. Gilmore >> wrote: >> >>> Except the RIRs won't give you another /48 when you have only used one >>> trillion IP addresses. >> >> Of course they will! A /48 is only the equivalent of 65536 "networks" >> (each >> network being a /64). Presuming that ISPs allocate /64 networks to each >> connected subscriber, then a /48 is only 65k subscribers, or say around a >> maximum of 200k IP addresses in use at any one time (presuming no NAT >> and an >> average of 3-4 IP-based devices per subscriber) >> >> IPv4-style utilization ratios do make some sense under IPv6, but not >> at the >> address level - only at the network level. > > First, it was (mostly) a joke. > > Second, where did you get 4 users per /64? Are you planning to hand > each cable modem a /64? > That was the generally accepted subnet practice last time I had a discussion about it on the ipv6-ops list. I'm not an ISP, but I have a /48 and each subnet is a /64. Some devices will refuse to work if you subnet smaller than a /64. (Yes, poorly designed, etc.) ~Seth
Re: Private use of non-RFC1918 IP space (IPv6-MW)
On Feb 4, 2009, at 6:56 PM, Scott Howard wrote: On Mon, Feb 2, 2009 at 9:35 PM, Patrick W. Gilmore wrote: Except the RIRs won't give you another /48 when you have only used one trillion IP addresses. Of course they will! A /48 is only the equivalent of 65536 "networks" (each network being a /64). Presuming that ISPs allocate /64 networks to each connected subscriber, then a /48 is only 65k subscribers, or say around a maximum of 200k IP addresses in use at any one time (presuming no NAT and an average of 3-4 IP-based devices per subscriber) IPv4-style utilization ratios do make some sense under IPv6, but not at the address level - only at the network level. First, it was (mostly) a joke. Second, where did you get 4 users per /64? Are you planning to hand each cable modem a /64? -- TTFN, patrick
Re: Private use of non-RFC1918 IP space (IPv6-MW)
On Mon, Feb 2, 2009 at 9:30 PM, Anthony Roberts wrote: > It has been my experience that when you give someone a huge address space > to play with (eg 10/8), they start doing things like using bits in the > address as flags for things. Suddenly you find yourself using a prefix > that should enough for a decent sized country in a half-rack. Which is, of course, a core design philosophy for IPv6. Stateless autoconfig relies on the fact that each network will be allocated 2^64 address. On Mon, Feb 2, 2009 at 9:35 PM, Patrick W. Gilmore wrote: > Except the RIRs won't give you another /48 when you have only used one > trillion IP addresses. Of course they will! A /48 is only the equivalent of 65536 "networks" (each network being a /64). Presuming that ISPs allocate /64 networks to each connected subscriber, then a /48 is only 65k subscribers, or say around a maximum of 200k IP addresses in use at any one time (presuming no NAT and an average of 3-4 IP-based devices per subscriber) IPv4-style utilization ratios do make some sense under IPv6, but not at the address level - only at the network level. Scott.
