nanog mailing list archives
Re: v6 subnet size for DSL & leased line customers
From: Mark Smith <nanog () 85d5b20a518b8f6864949bd940457dc124746ddc nosense org>
Date: Sun, 23 Dec 2007 18:25:23 +1030
On Sat, 22 Dec 2007 12:53:52 -0800 "Christopher Morrow" <morrowc.lists () gmail com> wrote:
On Dec 22, 2007 12:23 PM, Ross Vandegrift <ross () kallisti us> wrote:On Fri, Dec 21, 2007 at 01:33:15PM -0500, Deepak Jain wrote:For example... Within one's own network (or subnet if you will) we can absorb all the concepts of V4 today and have lots of space available. For example... for the DMZ of a business... Why not give them 6 bits (/122?) are we anticipating topology differences UPSTREAM from the customers that can take advantage of subnet differences between /64 and /56 ?I am confused on this point as well. IPv6 documents seem to assume that because auto-discovery on a LAN uses a /64, you always have to use a /64 global-scope subnet. I don't see any technical issues that require this though. ICMPv6 is capable of passing info on prefixes of any length - prefix length is a plain old 8bit field.Uhm, so sure the spec might be able to do something different than /64 but most equipment I've used only does auto-conf if the prefix is a /64 :( Somewhere along the path to ipng we got reverted to classful addressing again :(
Not really. Classful IPv4 defined both an addressing structure *and* an agorithm to match destinations against the route table entries (i.e. classful forwarding won't match on a default route if the router knows at least one prefix within a classful network). IPv6 uses the longest match rule regardless of any addressing structure, and only uses structure for a few portions of the total IPv6 address space, for the operation of things like DHCPv6 and address autoconfiguration. A change in IPv6 addressing structure won't involve a change in the route table matching algorithm. Regards, Mark. -- "Sheep are slow and tasty, and therefore must remain constantly alert." - Bruce Schneier, "Beyond Fear"
Current thread:
- Re: v6 subnet size for DSL & leased line customers, (continued)
- Re: v6 subnet size for DSL & leased line customers Randy Bush (Dec 26)
- Re: v6 subnet size for DSL & leased line customers Joel Jaeggli (Dec 28)
- Re: v6 subnet size for DSL & leased line customers Randy Bush (Dec 28)
- Re: v6 subnet size for DSL & leased line customers Mark Townsley (Dec 22)
- Re: v6 subnet size for DSL & leased line customers Christopher Morrow (Dec 22)
- Re: v6 subnet size for DSL & leased line customers Mark Smith (Dec 21)
- Re: v6 subnet size for DSL & leased line customers Steven M. Bellovin (Dec 21)
- Re: v6 subnet size for DSL & leased line customers Deepak Jain (Dec 21)
- Re: v6 subnet size for DSL & leased line customers Ross Vandegrift (Dec 22)
- Re: v6 subnet size for DSL & leased line customers Christopher Morrow (Dec 22)
- Re: v6 subnet size for DSL & leased line customers Mark Smith (Dec 22)
- Re: v6 subnet size for DSL & leased line customers Deepak Jain (Dec 24)
- Re: v6 subnet size for DSL & leased line customers Iljitsch van Beijnum (Dec 22)
- Re: v6 subnet size for DSL & leased line customers Mohacsi Janos (Dec 23)
- Re: v6 subnet size for DSL & leased line customers Randy Bush (Dec 23)
- Re: v6 subnet size for DSL & leased line customers Mohacsi Janos (Dec 24)
- Re: v6 subnet size for DSL & leased line customers Ross Vandegrift (Dec 23)
- Re: v6 subnet size for DSL & leased line customers Daniel Hagerty (Dec 23)
- Re: v6 subnet size for DSL & leased line customers Mark Smith (Dec 23)
- Re: v6 subnet size for DSL & leased line customers Joe Greco (Dec 23)
- Re: v6 subnet size for DSL & leased line customers Mark Smith (Dec 23)