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Date: Thu, 3 Jan 2008 04:21:18 -0500 From: "Rick Astley" <jnanog@gmail.com> To: nanog@merit.edu In-Reply-To: <b4504ba0801030052p2f67e3eeifd426e80c3be4c2e@mail.gmail.com> Errors-To: owner-nanog@merit.edu ------=_Part_15749_12927773.1199352078659 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Content-Disposition: inline On Jan 3, 2008 3:52 AM, Rick Astley <jnanog@gmail.com> wrote: > > >Take someone like Comcast with ~12 million subscribers. > > >It would take an IPv6 /24 to get 16.7 million /48's (2^24). With a net > efficiency of 10% they are going to need to be allocated 120 million /48's. > It would take a /21 to give them 2^(48-21) = ~134 million /48's. > > >So in short, a /48 to subscribers seems like complete overkill, and a /32 > to ISP's seems completely inadequate (80 vs 16 bits). > > >I thought one of the goals of IPv6 was to assign ISP's huge blocks with > low utilization so they don't have push a bunch of individual prefixes out > to the worlds routing tables? > > >It seems to me while being extra super sure we meet goal 1 of making sure > NAT is gone for ever (and ever) we fail goal 2 of not allocating a bunch of > prefixes to ISP's that are too small. > PS. say for example we would like to meet goal 2 while giving customers /48's at the same time. We decide a an initial projected utilization of 1% or .1% is more appropriate for Comcast. In order to give them 1.2 billion /48's (1% utilization), they would need 2 /18's. For 12 billion (0.1% utilization), they would need a /14. In which case the depletion of IPv6 space starts to seem possible. Your response might be "Why would an ISP need 0.1% utilization?" My answer: "Why would a customer need 0.000000000000000000000001%utilization?" ------=_Part_15749_12927773.1199352078659 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Content-Disposition: inline <br><br><div class="gmail_quote">On Jan 3, 2008 3:52 AM, Rick Astley <<a href="mailto:jnanog@gmail.com">jnanog@gmail.com</a>> wrote:<br><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;"> <br>>Take someone like Comcast with ~12 million subscribers.<br><br>>It would take an IPv6 /24 to get 16.7 million /48's (2^24). With a net efficiency of 10% they are going to need to be allocated 120 million /48's. It would take a /21 to give them 2^(48-21) = ~134 million /48's. <br><br>>So in short, a /48 to subscribers seems like complete overkill, and a /32 to ISP's seems completely inadequate (80 vs 16 bits).<br><br>>I thought one of the goals of IPv6 was to assign ISP's huge blocks with low utilization so they don't have push a bunch of individual prefixes out to the worlds routing tables? <br><br>>It seems to me while being extra super sure we meet goal 1 of making sure NAT is gone for ever (and ever) we fail goal 2 of not allocating a bunch of prefixes to ISP's that are too small.<br> </blockquote></div><br>PS. say for example we would like to meet goal 2 while giving customers /48's at the same time. We decide a an initial projected utilization of 1% or .1% is more appropriate for Comcast.<br><br> In order to give them 1.2 billion /48's (1% utilization), they would need 2 /18's.<br><br>For 12 billion (0.1% utilization), they would need a /14.<br>In which case the depletion of IPv6 space starts to seem possible. <br><br>Your response might be "Why would an ISP need 0.1% utilization?"<br>My answer: "Why would a customer need 0.000000000000000000000001% utilization?" ------=_Part_15749_12927773.1199352078659--
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