Proxy vs. broadcast solution

Two main approaches can be taken when requesting an IP address from nodes in a MANET. They are here referred to as the proxy solution and the broadcast solution.

If using the proxy solution, the unconfigured node elects one configured node that operates on behalf of it for the entire configuration session. In PAA this can be done, but the implementation on which this chapter is based, uses another approach. The main idea in the implementation of PAA, is that an unconfigured node is to be able be mobile while doing configuration. Because of this no proxy is used for configuration.

A node communicates with any configured nodes that are in communication range. Data is broadcasted from the unconfigured node and back from configured nodes. Because of this, this approach is called the broadcast solution. No state is kept in the configured nodes regarding configuration sessions. An unconfigured node can be mobile and use different configured nodes for different parts of the configuration process.

Both approaches have their pros and cons. The broadcast solution gives the advantage of mobility, but the proxy approach could provide a more robust DAD. If using a proxy, address conflict messages in strong DAD, can be unicasted back to the proxy node. When using the broadcast solution all such traffic is flooded throughout the MANET. Some specific scenarios where a node loses connectivity and does not receive conflicting messages could also be avoided when using the proxy solution, but new such problematic scenarios could be generated for the proxy solution as well.

Andreas 2004-07-29