Intelligent Transport Systems (ITS) and the open-ended
research in the field of vehicular communication attempts
to deal with the road traffic problems. In Vehicular Ad-Hoc
Networks (VANETs), vehicles are moving faster in comparison
with Mobile Ad-hoc Networks (MANETs). Furthermore, in urban
VANETs, vehicles are constrained by the layout of the roads and
buildings, which causes shadowing effects. On the other hand,
ITS promises traffic management, road safety and comfort applications,
that have their Quality-of-Service (QoS) requirements.
Thus, one of the key factors to the successful establishment of
VANETs is a routing protocol to meet these QoS requirements.
Geo-routing protocols are appropriate for VANETs, as a result
of their simplicity, efficiency, and scalability. Because of the large
number of the proposed geo-routing protocols, it is requisite to
have a comprehensive collection of the materials on this topic to
provide a solid background for a research paper¡¯s investigation.
This paper presents an overview of the state of the art geo-routing
protocols for urban VANETs.