  Ad hoc networking specific challenges foster a strong research effort on
efficient protocols design. Routing protocols based on a self-organized
structure have been studied principally for the robustness and the scalability
they provide. On the other hand, self-organization schemes may decrease the
network capacity since they concentrate the traffic on privileged links. This
paper presents four models for evaluating the capacity of a routing schemes on
802.11 like networks. Our approach consists in modeling the radio resource
sharing principles of 802.11 like MAC protocols as a set of linear constraints.
We have implemented two models of fairness. The first one assumes that nodes
have a fair access to the channel, while the second one assumes that on the
radio links. We then develop a pessimistic and an optimistic scenarii of
spatial re-utilization of the medium, yielding a lower bound and an upper bound
on the network capacity for each fairness case. Our models are independent of
the routing protocols and provide therefore a relevant framework for their
comparison. We apply our models to a comparative analysis of the well-known
shortest path base flat routing protocol OLSR against two main self-organized
structure approaches, VSR, and Wu & Li's protocols. This study concludes on the
relevance of self-organized approaches from the network capacity point of view.
