Ljubica Blazevic

Self organization in mobile ad hoc networks: the approach of Terminodes

The Terminodes project is designing a wide-area mobile ad hoc network which is meant to be used in a public environment; in our approach, the network is run by users themselves. We give a global description of the building blocks used by the basic operation of the network; they all rely on various concepts of self-organization. Routing uses a combination of geography-based information and local MANET-like protocols. Terminode positioning is obtained by either GPS or a relative positioning method. Mobility management uses self-organized virtual regions. Terminodes employ a form of virtual money called nuglets as an incentive to collaborate. Lastly, we discuss directions for providing some level of security.

A location-based routing method for mobile ad hoc networks

Using location information to help routing is often proposed as a means to achieve scalability in large mobile ad hoc networks. However, location-based routing is difficult when there are holes in the network topology and nodes are mobile or frequently disconnected to save battery. Terminode routing, presented here, addresses these issues. It uses a combination of location-based routing (terminode remote routing, TRR), used when the destination is far, and link state-routing (terminode local routing, TLR), used when the destination is close. TRR uses anchored paths, a list of geographic points (not nodes) used as loose source routing information. Anchored paths are discovered and managed by sources, using one of two low overhead protocols: friend assisted path discovery and geographical map-based path discovery. Our simulation results show that terminode routing performs well in networks of various sizes. In smaller networks; the performance is comparable to MANET routing protocols. In larger networks that are not uniformly populated with nodes, terminode routing outperforms, existing location-based or MANET routing protocols.

Towards mobile ad-hoc WANs: terminodes

Terminodes are personal devices that provide functionality of both the terminals and the nodes of the network. A network of terminodes is an autonomous, fully self-organized, wireless network, independent of any infrastructure. It must be able to scale up to millions of units, without any fixed backbone or server. In this paper we present the main challenges and discuss the main technical directions.

Distributed core multicast (DCM): a multicast routing protocol for many groups with few receivers

We present a multicast routing protocol called Distributed Core Multicast (DCM). It is intended for use within a large single Internet domain network with a very large number of multicast groups with a small number of receivers. Such a case occurs, for example, when multicast addresses are allocated to mobile hosts, as a mechanism to manage Internet host mobility or in large distributed simulations. For such cases, existing dense or sparse mode multicast routing algorithms do not scale well with the number of multicast groups. DCM is based on an extension of the centre-based tree approach. It uses several core routers, called Distributed Core Routers (DCRs) and a special control protocol among them. DCM aims: (1) avoiding multicast group state information in backbone routers, (2) avoiding triangular routing across expensive backbone links, (3) scaling well with the number of multicast groups. We evaluate the performance of DCM and compare it to an existing sparse mode routing protocol when there is a large number of small multicast groups. We also analyse the behaviour of DCM when the number of receivers per group is not a small number.

Self organized routing in wide area mobile ad-hoc networks

This paper considers the problem of routing in a wide area mobile ad-hoc network called terminode network. Our routing scheme is a combination of two protocols called terminode local routing (TLR) and terminode remote routing (TRR). TRR is activated when the destination is remote and uses location of the destination obtained either via location management or by location tracking. TLR acts when the packet gets close to the destination. The use of TRR results in a scalable solution that reduces dependence on the intermediate systems, while TLR allows us to reduce problems due to location inaccuracy. The paper describes TLR and TRR protocols and presents some simulation results.

Distributed Core Multicast (DCM): A Multicast Routing Protocol for Many Groups with Few Receivers

We present a multicast routing protocol called Distributed Core Multicast (DCM). It is intended for use within a large single Internet domain network with a very large number of multicast groups with a small number of receivers. Such a case occurs, for example, when multicast addresses are allocated to mobile hosts, as a mechanism to manage Internet host mobility or in large distributed simulations. For such cases, existing dense or sparse mode multicast routing algorithms do not scale well with the number of multicast groups. DCM is based on an extension of the centre-based tree approach. It uses several core routers, called Distributed Core Routers (DCRs) and a special control protocol among them. DCM aims: (1) avoiding multicast group state information in backbone routers, (2) avoiding triangular routing across expensive backbone links, (3) scaling well with the number of multicast groups. We evaluate the performance of DCM and compare it to an existing sparse mode routing protocol when there is a large number of small multicast groups.

Issues on mobile ad-hoc WANs

The authors present the main challenges in mobile ad-hoc wide area networks (MAWANs). A MAWAN is a wide area, large, (potentially) entirely wireless networks. We describe the Terminodes Project that investigates issues and challenges in MAWANs. The name of the project comes from the fact that the elements of the network act as nodes and terminals at the same (terminodes).