Independent thesis Advanced level (professional degree), 20 credits / 30 HE credits
Wireless communication has grown very popular, and communication is the key
to success in many situations. However, most of the common technologies today
rely on infrastructure and in disaster situations infrastructure might be lost or
get severely overloaded. This master thesis concerns intermittently connected
mobile ad hoc networks. A network in which the devices may move freely in any
direction and still be able to communicate. To be able to demonstrate a network
protocol called random-walk gossip-based manycast (RWG) my assignment has been
to implement this protocol using oﬀ-the-shelf hardware and software.
RWG is a multi-hop and partition-tolerant mobile ad hoc manycast network
protocol. Multi-hop refers to information being able to hop between more than
two nodes in a network and partition-tolerant means that the protocol works even
though a network is partitioned. Manycast means that the information should
be successfully delivered to K of all the potential nodes in the area. The RWG
protocol makes use of four diﬀerent packet types, request to forward (REQF), ac-
knowledgement (ACK), ok to forward (OKTF) and be silent (BS). The actual data
being sent is carried by REQFs, and is referred to as messages. When a message
is sent it takes what could be described as a random walk among the nodes in the
network, hence the name.
The implementation of the RWG protocol resides in user-space and depends on
the IEEE 802.11b standard and the raw socket that is speciﬁed in the BSD socket
API. It is written in C and was developed on a machine running Ubuntu. It runs
on systems that use Linux 2.6 kernels and it supports cross-compiling for ARM
based devices such as the Nokia N810 internet tablet and the Android dev phone
1. To be able to demonstrate the protocol I developed my own client application.
Moreover, an already existing application for Android, Portable Open Search and
Identiﬁcation Tool (POSIT), was successfully extended to run on top of the RWG
implementation. The extension was developed by people in the POSIT project
and tested in a physical experiment covering ﬁve devices.
The report covers the RWG protocol, the system choice, the implementation
and the testing of the implementation.
2009. , 99 p.
mobile ad hoc network, multi-hop, partition tolerance, random-walk gossip-based manycast
Asplund, Mikael, Ph.D. Student