Funny, "On the other hand I see enormous value in allowing any size of network on any customer's premises. It's not for this generation of engineers and ISPs to constrain what our great-grandchildren might invent" is something I see as an argument for sticking with /64s. You never know what may be developed that needs all those host bits (or, atleast - needs more than we expect ... think things like per-sessions IP addresses and such 'craziness' :) )
Thanks! /TJ >-----Original Message----- >From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of >Dunn, Jeffrey H. >Sent: Wednesday, October 01, 2008 11:04 PM >To: Brian E Carpenter >Cc: Alexandru Petrescu; ipv6@ietf.org; [EMAIL PROTECTED]; >[EMAIL PROTECTED]; [EMAIL PROTECTED]; Sherman, Kurt T.; draft-ietf- >[EMAIL PROTECTED]; [EMAIL PROTECTED]; [EMAIL PROTECTED]; >[EMAIL PROTECTED]; [EMAIL PROTECTED]; Martin, Cynthia E. >Subject: RE: what problem is solved by proscribing non-64 bit prefixes? > >Brian, > >Your point about raising the size of the address space to the fourth power >is not quite correct. If we constrain the network prefix to be 64-bits, >then, assuming that the longest routable IPv4 prefix is 24, we have only >raised the prefix size by the power 2.67. Now assume that we start handing >out /28 prefixes to ISPs for their residential customers (who are now all >behind a NAT), we have now only raised the number of subnets to the 1.17. My >argument is that it is not the number of unique end system addresses that is >the issue, rather the number of subnets. > >As to your observation concerning this generation's engineers, I whole >heartedly second your suggestion. > >Best Regards, > >Jeffrey Dunn >Info Systems Eng., Lead >MITRE Corporation. >(301) 448-6965 (mobile) > > >-----Original Message----- >From: Brian E Carpenter [mailto:[EMAIL PROTECTED] >Sent: Wednesday, October 01, 2008 4:43 PM >To: Dunn, Jeffrey H. >Cc: Alexandru Petrescu; [EMAIL PROTECTED]; Sherman, Kurt T.; >ipv6@ietf.org; [EMAIL PROTECTED]; [EMAIL PROTECTED]; >[EMAIL PROTECTED]; [EMAIL PROTECTED]; >[EMAIL PROTECTED]; [EMAIL PROTECTED]; [EMAIL PROTECTED]; v6ops- >[EMAIL PROTECTED]; Martin, Cynthia E. >Subject: Re: what problem is solved by proscribing non-64 bit prefixes? > >On 2008-10-02 02:04, Dunn, Jeffrey H. wrote: >> More to the point, what would a individual household do with >Avogadro's >> number worth of IPv6 addresses (2^80 = 1.2x10^24)? This seems >> extremely wasteful. Further, a reasonable sized ISP with a couple of >> million customers would require a /28 or more just for their >> residential customer base. This sounds like a prescription for >address >> exhaustion. > >Not in the least. Please remember that we have raised the size of the >address space to the *fourth* power; we squared it and squared it again. >Even if we'd stuck to the original plan of assigning /48s everywhere, that >means we've *squared* the size of the subnet prefix space (/24 to /48). >Unless really stupid allocation mechanisms are allowed, that is enough for >any imaginable future. And all the evidence is that the RIRs are being >extremely conservative in their practices for allocation. So I don't see >even a remote cause for concern. > >On the other hand I see enormous value in allowing any size of network on >any customer's premises. It's not for this generation of engineers and ISPs >to constrain what our great-grandchildren might invent. > > Brian >-------------------------------------------------------------------- >IETF IPv6 working group mailing list >ipv6@ietf.org >Administrative Requests: https://www.ietf.org/mailman/listinfo/ipv6 >-------------------------------------------------------------------- -------------------------------------------------------------------- IETF IPv6 working group mailing list ipv6@ietf.org Administrative Requests: https://www.ietf.org/mailman/listinfo/ipv6 --------------------------------------------------------------------
