Fast Duplicate Address Detection for Mobile IPv6

Several components contribute to handover delay of mobile IPv6, namely, movement detection time, address configuration time, binding registration time, and route optimization time. Through testbed experiments, we found that the dominating delay component is the address configuration time, which is the time required to configure a new globally routable IPv6 address on the mobile node after it moves to a foreign network. A typical process of IPv6 address configuration requires a duplicate address detection (DAD) procedure. During DAD, a mobile node sends a neighbor solicitation message to ask whether its new address is being used. If no node replies within a set timer, a mobile node can assume the new address is unique on that network. On the Linux testbed, DAD takes as much as 1 second, which causes intolerable disruption in case of time-critical applications. This work studies techniques for reducing delay during the DAD procedure. Main contributions of this work are the insights into benefits and shortcomings of different DAD techniques, as well as benchmarks for design of future DAD protocols.