  The inability of practical MANET deployments to scale beyond about 100 nodes
has traditionally been blamed on insufficient network capacity for supporting
routing related control traffic. However, this paper points out that network
capacity is significantly under-utilized by standard MANET routing algorithms
at observed scaling limits. Therefore, as opposed to identifying the scaling
limit for MANET routing from a capacity stand-point, it is instead
characterized as a function of the interaction between dynamics of path failure
(caused due to mobility) and path repair. This leads to the discovery of the
repair time scaling wall, which is used to explain observed scaling limits in
MANETs. The factors behind the repair time scaling wall are identified and
techniques to extend the scaling limits are described.
