On 11-aug-2005, at 2:23, Kevin Loch wrote:
And on that vein perhaps it's prudent for people using network prefixes longer than /64 to take care to ensure that the bit positions in the IPv6 address that should correspond to the u and g bits in the modified EUI-64 interface ID (according to RFC 3513) are both set to
Is there any known use for those bits?
The universal/local bit is copied from the EUI-64/MAC address and flipped, and indicates whether the address is derived from something (supposedly) globally unique or not. Both occur frequently, non- unique stem from manual configuration or RFC 3041 temporary/privacy addresses. The group bit isn't relevant, although you won't see MAC- derived addresses with this bit set, of course. There is no real reason to preserve these bits when the prefix length is > 64.