RFC 1897 IPv6 Testing Address Allocation January 1996 2.0 Address Format The address format for the IPv6 test address is consistent with the provider-based unicast address allocation [PRVD] which is as follows: | 3 | 5 bits | 16 bits | 8 | 24 bits | 8 | 64 bits | +---+----------+----------+---+------------+---+----------------+ |010|RegistryID|ProviderID|RES|SubscriberID|RES|Intra-Subscriber| +---+----------+----------+---+------------+---+----------------+ The specific allocation of each field of the test address format is as follows: | 3 | 5 bits | 16 bits | 8 | 24 bits | 8 | 16 bits|48 bits| +---+----------+----------+---+------------+---+--------+-------+ | | |Autonomous| | IPv4 | | Subnet | Intf. | |010| 11111 | System |RES| Network |RES| | | | | | Number | | Address | | Address| ID | +---+----------+----------+---+------------+---+--------+-------+ where: 010 This is the Format Prefix used to identify provider-based unicast addresses. 11111 This is a Registry ID reserved by the IANA. The initial use of addresses in this Registry ID for IPv6 testing is temporary. All users of these addresses will be required to renumber at some time in the future. Autonomous System Number This is the current autonomous system number assigned to the provider providing internet service to the an IPv6 testers organization. For example for IPv6 testers receiving internet service from BBN Barrnet would use autonomous system number 189. This would be coded in the autonomous system field of the address as follows: 0000 0000 1011 1101 (binary) Hinden & Postel Experimental