32bit IDs A lot of protocols use 32bit IDs 32bit IDs = management headaches, scalability limitation What is the domain of uniqueness? BGP, OSPF - within an AS NTP - worldwide uniqueness needed How wide does ID need to be? 128bit - global IPv6 address can be used 64bit - EUI64 maybe? (not guaranteed to be unique) 64bit - 32bit AS number + 32bit serial (management headache) 32bit - insufficient (32bit AS numbers) Scoped IPv6 address and IDs?