Autoconfiguartion in Wireless Mesh Networks

In MANETs or WMNs nodes communicate directly with other nodes within their wireless transmission range (single-hop communication). With all other participating nodes they communicate using intermediate nodes as relays (multi-hop communication). The solution for IP address autoconfiguration in spontaneous, local networks mentioned above implies that all participants are able to communicate directly. Thus, their application to spontaneous, wireless multi-hop networks is impossible.

Since about 2000 several research groups have addressed this problem and have been developing specific solutions for autoconfiguration in wireless multi-hop networks, especially in MANETs. The existing proposals can be classified mainly into three different categories.

The first category uses conflict-detection allocation methods, especially before address assignment. Some approaches also perfom this during operation. Such a continuous verification is crucial since one part of the MANET nodes might lose the connection to an other, may it be by node failure or by collective node departure. Out of this, independent MANETs arise, partitions which might allocate addresses on their own. If such partitions merge later on into a single MANET it will be possible that addresses are now allocated multiple times.

The second category performs conflict-free allocation. It guarantees that adresses are never allocated multiple times. However, there it is possible that MANETs merge which were never connected before and, therefore, address conflicts occur. So, approaches using such methods must consider partition and merging, too.

Approaches of the third category introduce best-effort allocation methods. They try to allocate addresses which are unassigned to the best of their knowledge. Since their knowledge is only partial they use conflict-detection to ensure a conflict-free allocation.

Since about 2004 specific solution for hybrid MANETs, i.e., MANETs with one or more gateways, have been in the works. In principle, these approaches are applicable to WMNs. However, they do not take advantage of the existing wireless infrastructure in WMNs, likewise the autoconfiguration in pure MANETs. This hierachical infrastructure may lead to more effcient methods than in MANETs.

In comparison to MANETs, WMNs show a couple of special features. They are built upon the idea of mobile ad-hoc networks but furthermore they offer the following: wireless infrastructure to improve network coverage, connectivity, and stability; integration of conventional wireless devices by gateway/bridge functionality; dedicated assignment of routing and configuration tasks to the infrastructure; multiple radios to seperate infras- tructure from client traffc enhancing overall throughput; and mobility more independent from end-user devices.