Hi all, As quoted from "IPv6 Transition Mechanism" [RFC1933], "...The tunnel endpoint is the node to which the IPv6 packet is addressed. Since the endpoint of the tunnel is the destination of the IPv6 packet, the tunnel endpoint can be determined from the destination IPv6 address of that packet: If that address is an IPv4-compatible address, then the low-order 32-bits hold the IPv4 address of the destination node, and that can be used as the tunnel endpoint address."
Unfortunately, the usage of IPv4-compatible address may cause routing scalability issue for IPv6 in practice when multiple sites use such addresses. The ISATAP (RFC5214) solves the above routing scalability issue with the automatic tunneling address by concatenating a /64 LIR prefix and an ISATAP interface ID (which is constructed in the Modified EUI-64) to generate an IPv6 Global unicast address. I wonder whether it is better to directly concatenate a /96 LIR prefix (which can be learnt from the prefix information option in the RA message) and a 32-bit IPv4 address to generate an IPv6 address. One obvious benefit of this method is IPv6 prefix resource can be allocated in a more efficient way. By the way, the IPv6 DAD action can also be avoided since the IPv4 address is already guaranteed to be unique. Xiaohu _______________________________________________ Softwires mailing list [email protected] https://www.ietf.org/mailman/listinfo/softwires
