v6 & DSL / Cable modems [was: Private use of non-RFC1918 IP space (IPv6-MW)]

Thu Feb 5 00:38:34 UTC 2009

Patrick W. Gilmore wrote:
> On Feb 4, 2009, at 7:08 PM, Seth Mattinen wrote:
>> Patrick W. Gilmore wrote:
>>>
>
>>> 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.)
>
> I Am Not An ISP either. :)
>
> I guess I was thinking about v4 modems which do not get a subnet, just
> an IP address.  If we really are handing out a /64 to each DSL & Cable
> modem, then we may very well be recreating the same problem.
>
> And before anyone says "there are 281474976710656 /48s!", just
> remember your history.  I was not there when v4 was spec'ed out, but I
> bet when someone said "four-point-two BILLION addresses", someone else
> said "no $@#%'ing way we will EVER use THAT many...."
>

Ah, but RFC 760, before 791, did assume "more than 253 networks? Nahhh..."