nanog mailing list archives
Re: Using IPv6 with prefixes shorter than a /64 on a LAN
From: Owen DeLong <owen () delong com>
Date: Fri, 4 Feb 2011 16:06:03 -0800
On Feb 4, 2011, at 8:50 AM, bmanning () vacation karoshi com wrote:
On Fri, Feb 04, 2011 at 08:28:53AM -0600, Jack Bates wrote:On 2/4/2011 5:03 AM, Eugen Leitl wrote:Given http://weblog.chrisgrundemann.com/index.php/2009/how-much-ipv6-is-there/ it is pretty clear the allocation algorithms have to change, or the resource is just as finite as the one we ran out yesterday.That's not what the author says. It says, IPv6 is only somewherein the range of 16 million to 17 billion times larger than IPv4.presuming you don't adhere to the guidelines that insist on the bottom 64 bits being used as a "MAC" address and the top 32 bits being used as an RIR identifier.
1. The top 12 bits identify the RIR, not the top 32. 2. The bits somewhere between 12 and 32 identify the LIR or ISP. 3. Those facts do not reduce the available number of network numbers. Yes, EUI-64 could be argued to impinge on that, except that EUI-64 only addresses the lower 64 bits. The upper 64 bits provide about 17 billion times as many network numbers as there are host numbers in IPv4. That's without accounting for the fact that ~25% of the IPv4 addresses are unusable as unicast host addresses.
in reality, IPv6 (as specified by many IETF RFCs and as implemented in lots of codes bases) only has 32 usable bits... just like IPv4.
Um, in reality, no, that is NOT the case.
Let's be realistic. A /32 (standard small ISP) is equiv to an IPv4 single IP. A /28 (medium ISP) is equiv to an IPv4 /28. A /24 (high medium, large ISP) is equiv to an IPv4 /24. A /16 (a huge ISP) is equiv to an IPv4 /16. Get the picture?sho'huff. the real question is, how will you manage your own 32bits of space? this is a change from the old v4 world, when the question was, how will you manage your (pre CIDR) 8bits (or 16bits, or 24bits) of space?
Among others. Owen
Current thread:
- Re: Using IPv6 with prefixes shorter than a /64 on a LAN, (continued)
- Re: Using IPv6 with prefixes shorter than a /64 on a LAN Jack Bates (Feb 01)
- Re: Using IPv6 with prefixes shorter than a /64 on a LAN Owen DeLong (Feb 01)
- Re: Using IPv6 with prefixes shorter than a /64 on a LAN Jack Bates (Feb 01)
- Re: Using IPv6 with prefixes shorter than a /64 on a LAN Fernando Gont (Feb 02)
- Re: Using IPv6 with prefixes shorter than a /64 on a LAN Rob Evans (Feb 03)
- Re: Using IPv6 with prefixes shorter than a /64 on a LAN Fernando Gont (Feb 03)
- Re: Using IPv6 with prefixes shorter than a /64 on a LAN George Herbert (Feb 03)
- Re: Using IPv6 with prefixes shorter than a /64 on a LAN Eugen Leitl (Feb 04)
- Re: Using IPv6 with prefixes shorter than a /64 on a LAN Jack Bates (Feb 04)
- Re: Using IPv6 with prefixes shorter than a /64 on a LAN bmanning (Feb 04)
- Re: Using IPv6 with prefixes shorter than a /64 on a LAN Jack Bates (Feb 04)
- Re: Using IPv6 with prefixes shorter than a /64 on a LAN Owen DeLong (Feb 04)
- Re: Using IPv6 with prefixes shorter than a /64 on a LAN Mark Andrews (Feb 04)
- Re: Using IPv6 with prefixes shorter than a /64 on a LAN Jack Bates (Feb 04)
- Re: Using IPv6 with prefixes shorter than a /64 on a LAN Mark Andrews (Feb 04)
- Re: Using IPv6 with prefixes shorter than a /64 on a LAN Jack Bates (Feb 04)
- Re: Using IPv6 with prefixes shorter than a /64 on a LAN Mark Andrews (Feb 05)
- Re: Using IPv6 with prefixes shorter than a /64 on a LAN Jack Bates (Feb 05)
- Re: Using IPv6 with prefixes shorter than a /64 on a LAN Mark Andrews (Feb 05)
- Re: Using IPv6 with prefixes shorter than a /64 on a LAN Jack Bates (Feb 05)
- Re: Using IPv6 with prefixes shorter than a /64 on a LAN Mark Andrews (Feb 05)
- Re: Using IPv6 with prefixes shorter than a /64 on a LAN Jack Bates (Feb 05)
- Re: Using IPv6 with prefixes shorter than a /64 on a LAN Rob Evans (Feb 03)