dynamic or static IPv6 prefixes to residential customers

Tue Aug 2 14:32:38 UTC 2011

In message <877h6w9emi.fsf at nemi.mork.no>, =?utf-8?Q?Bj=C3=B8rn_Mork?= writes:
> JORDI PALET MARTINEZ <jordi.palet at consulintel.es> writes:
> 
> > I will like to know, from those deploying IPv6 services to residential
> > customers, if you are planning to provide static or dynamic IPv6 prefixes.
> >
> > Just to be clear, I'm for static prefix delegation to residential
> > customers, however I heard that some ISPs are doing dynamic delegations,
> > the same way as is common today with IPv4.
> >
> > I don't thin it make sense, as the main reason for doing so in IPv4 was
> > address exhaustion and legacy oversubscription models such as PPP/dial-up.
> 
> We will do "semi-static" PD for residential users.  In practice most
> users will see this as static, but we may reallocate users if necessary
> to preserve aggregation.
> 
> One point I often miss in the endless discussions wrt dynamic/static
> IPv6 with references to the dynamic IPv4 world, is the lack of RFC1918
> addressing for IPv6.  The fact is that all residential users are used
> to, and depend on, static IPv4 addressing within their own network.
> They assign e.g. 192.168.5.5 to their printer and 192.168.5.6 to their
> NAS, and trust that those addresses are static.
> 
> Now moving to IPv6, their choices are either link local or a static
> delegated prefix.  Link local will of course work and be completely
> static for a given device, but does have a couple of drawbacks which I
> believe will make most users want a static global prefix instead:
> - ugly addresses, often not configurable
> - the need to specify outgoing interface on any PC/whatever you want to
>   talk to the link local addresss
> 
> For this reason, I argue that residential users are used to static IPv4
> addresses and will demand static IPv6 addresses.  The fact that their
> globally routed IPv4 address is dynamic is completely irrelevant as long
> as a similar mechanism isn't available for IPv6 (no, I won't mention
> NAT66).=20

en1: flags=8863<UP,BROADCAST,SMART,RUNNING,SIMPLEX,MULTICAST> mtu 1500
	ether 60:33:4b:01:75:85 
	inet6 fe80::6233:4bff:fe01:7585%en1 prefixlen 64 scopeid 0x5 
	inet 192.168.191.223 netmask 0xffffff00 broadcast 192.168.191.255
	inet6 fd92:7065:b8e::6233:4bff:fe01:7585 prefixlen 64 autoconf 
	inet6 2001:470:1f00:820:6233:4bff:fe01:7585 prefixlen 64 autoconf 
	media: autoselect
	status: active

Note the multiple prefixes.  IPv6 is not just IPv4 with bigger addresses.
If you want to give your printers, etc. stable IPv6 addesses use ULAs.

> Bj=C3=B8rn
> 
-- 
Mark Andrews, ISC
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742                 INTERNET: marka at isc.org