UAv6: Alias Resolution in IPv6 Using Unused Addresses

Ramakrishna Padmanabhan, Zhihao Li, Dave Levin, and Neil Spring

Alias resolution is the process of grouping interface addresses (usually obtained from traceroutes) onto their corresponding routers. A network map constructed purely from traceroute-derived interface addresses will overestimate the number of routers. Alias resolution reduces an interface-level map derived from traceroutes to a router-level map, rendering a more accurate picture of the actual network topology.

UAv6 is a new alias resolution technique for IPv6. The first “harvest” phase gathers potential alias pairs, and is based on our empirical observation that addresses adjacent to router interface addresses are often unused. UAv6 probes these unused addresses, eliciting ICMPv6 Address Unreachable responses. The central assumption of this work is that the source address of such a response belongs to a router directly connected to the prefix containing the unused and router interface addresses. The second “disambiguation” phase determines which interface address is an alias of the Address Unreachable’s source address. UAv6 uses both new and established techniques to construct proofs or disproofs that two addresses are aliases.