Private use of non-RFC1918 IP space (IPv6-MW)
nanog at daork.net
Thu Feb 5 03:19:54 UTC 2009
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,
> 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::ffff:ffff:ffff:0/112 = /
112 link nets between ISP routers ( 281474976710656 )
-- 2001:db8:0::/64 through 2001:db8:0:ffff::/64 = ISP networks, ie.
- 2001:db8:1::/64 through 2001:db8:ffff:ffff::/64 = customer networks.
Assuming the above, we have 65535 /48s available to customers, or
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.
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