Mobile Slotted Aloha (MS-Aloha) is a wireless network protocol proposed for applications such as vehicle networks.
Considering the typical taxonomy of MAC protocols, MS-Aloha represents a hybrid solution. It is based on connection-oriented paradigm (hence may fall in the class of channel-based/TDMA protocols); however it is also very reactive to topology changes and does not include any reservations separate from data exchanges. It is classified among the packet-based and collision-free MAC methods.[citation needed]
In general, a slotted protocol can be either connectionless or connection-oriented. However, only the latter case represents a true alternative to IEEE 802.11p, by introducing the determinism which carrier sense multiple access with collision avoidance (CSMA/CA) lacks. In vehicle networks the connection set-up phases of a telephone call (reservation request, confirmation, data exchange, tear-down) cannot be applied (it does not hold for broadcast communications, it is hampered by hidden stations, it is not manageable with heavy losses, mobility and varying channel conditions). For these reasons MS-Aloha is connection oriented and continuously refreshes each reservation simply by transmitting each period. MS-Aloha adopts a different approach and subtends the following hypotheses and rules which, basically, define all its main mechanisms.[citation needed]