Re:IPv6: Not Ready For Prime Time (Score 1)

128 bits for IPv6 addresses are divided into a 64 bit "network id" and a 64 bit "host id". The 64 bit network id isn't overkill. You could argue that, given allocation realities, and the need for several levels of aggregation, that it isn't enough.

But 64 bits for the host id does seem excessive. Most of the time, it is onlynecessary to provide enough bits to uniquely identify a host within its network. 64 bits is considerably more than is required for this, and is enough to give every host a globally unique identifier independent of the network ids. In fact, most hosts will have a host id that is based on their unique MAC address, and even this would have required only 48 bits. The long host ids were done to permit autoconfiguration. But they raise privacy issues, and it doesn't seem logical to me that every one of trillions of network packets needs to carry a globally unique host id for the sake of an autoconfiguration event that happens only when the host joins the network.