Brian and James,I should have been more specific - my comments were for BNG/BRAS (as that is the space I play in) that describe a situation where the ISP needs to change the original prefix (call it prefix-A) to a new prefix (call it prefix-B).
Yes, IPv6 the protocol and DHCPv6 Prefix Delegation support such a concept (delegating a new prefix(-B) and allowing the lifetime to expire on prefix-A while allowing both to be routed). I was pointing out that this will (in my view) consume needless resources on a BNG/ BRAS ultimately limiting the scalability and increasing the cost for carriers to adopt IPv6. This will also be increase implementation complexity as now the subscriber has (up to) three DHCP states - DHCPv4, DHCPv6 Prefix-A and DHCPv6 Prefix-B - for the BNG (and the ISP) to keep track of.
We would rather avoid the need for such a requirement and keep to a single "static" prefix per subscriber. As Mikael said (and I agree with), subscriber do not want the global-unicast addresses on their LAN to change.
-d On 04/01/2008, at 3:47 PM, Brian E Carpenter wrote:
On 2008-01-04 16:00, james woodyatt wrote:On Jan 3, 2008, at 18:25, David Miles wrote:Actually, no it isn't. The IPv6-enabled Internet gateway my employer sells today does this. Every time the public IPv4 address changes, the IPv6 6to4 interior prefix moves.While IPv6 supports it, it would be resource intensive for edge routers to support transitioning from one prefix to another with multiple prefixes simultaneously active.That's not quite the same as running with several simultaneous prefixes, though. I agree that this ought to work painlessly too, since it's a design feature of IPv6, but the CPE will have to actually support it, and so will all the consumer devices. Brian