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Summary: A Robust Push-to-Talk Service for Wireless Mesh Networks
Yair Amir, Raluca Musaloiu-Elefteri, Nilo Rivera
Department of Computer Science, Johns Hopkins University
Abstract--Push-to-Talk (PTT) is a useful capability for rapidly
deployable wireless mesh networks used by first responders. PTT
allows several users to speak with each other while using a single,
half-duplex, communication channel, such that only one user
speaks at a time while all other users listen.
This paper presents the architecture and protocol of a robust
distributed PTT service for wireless mesh networks. The architec-
ture supports any 802.11 client with SIP-based (Session Initiation
Protocol) VoIP software and enables the participation of regular
phones. Collectively, the mesh nodes provide the illusion of a
single third party call controller, enabling clients to participate
via any reachable mesh node. Each PTT group instantiates its
own logical floor control manager that is highly available and
resilient to mesh connectivity changes such as node crashes and
recoveries and network partitions and merges. Experimental
results on a fully deployed mesh network consisting of 14 mesh
nodes and tens of emulated clients demonstrate the scalability
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