*3.9.1. Cluster stability*

Cluster stability is based on the selection of suitable CMs to ensure greater cluster lifetimes by reducing cluster re-configuration events. Cluster stability also depends on the different vehicle densities. To be able to form stable clusters of one hop vehicles, vehicular movements should be taken in to account. Speed and location data transfer is a usual procedure in most of the cluster-based routing protocols. Nevertheless, this needs two additional communication rounds (for speed, location and relative stability data transfer) and stationary assumption of vehicles prior to cluster creation. Cluster stability can be defined as the average number of cluster changes throughout the simulation and the percentage of time in which vehicles were CMs, represented as association time. In practical environment effects of multi path fading are bound to affect the cluster creation method and thus stability. In some cases, nodes in cluster are linked to cluster rather than CH. This increase furthers the cluster stability.
