is a routing protocol for multi-hop mobile ad hoc networks which is under development by the German "Freifunk" community and intended to replace the Optimized Link State Routing Protocol (OLSR) as OLSR did not meet the performance requirements of large-scale mesh deployments.

's crucial point is the decentralization of knowledge about the best route through the network — no single node has all the data.

Instead of manipulating routing tables based on information exchanged via UDP/IP, it provides a virtual network interface and transparently transports Ethernet packets on its own.

As radio networks undergo constant changes and low participation-thresholds are a vital part of the "Freifunk"-networks' foundation, this task has to be automated as much as possible.

For the sending and receiving of originator-messages (information about existence), the UDP port 1966 was chosen.

can be deployed in a central location, such as a tall building, and have several wired or wireless network interfaces attached to it.

Certain unusual phenomena and special circumstances could appear during the determination of the best route through the network.

has been shown to exhibit high levels of stability but slightly slow convergence times in real-world conditions;[7] this is confirmed by theoretical analysis.

[8] BatMan-eXperimental (BMX) aims to approximate the real exponent by also sending OGMs (originator messages) multiple times in independent broadcast datagrams.

[10] An extended version that incorporates securely-entrusted multi-topology routing (SEMTOR) is called BMX7.

[11] [12] Version four implements an algorithm to better detect quality of transmissions in abnormal link situations.

Originator messages are updated to incorporate this data, enabling other nodes to better sense quality of asymmetric connections.

was written on a whiteboard in the HBO series Silicon Valley (Season 4 Episode 2) where the show's lead character Richard Hendricks appears to include B.A.T.M.A.N.