implementation of ad-hoc mesh network

Jadavpur University

Centre for Mobile Computing & Communication

Implementation of Ad-Hoc Mesh Network

Presentation by:

Sudipto DasRajesh Roy

Jadavpur University


Presentation Outline

Ad-hoc Mesh Network – an overview

Advantages Motivation and Practical Applications Implementation at Jadavpur University

Campus Looking ahead : Possible enhancements

Jadavpur University



Mesh network corresponds to a mix of ad-hoc and “Infrastructure” or “AP Based” approach.

The ad-hoc component of the mesh deals with• mesh devices communicating with each other• co-operation in forwarding traffic of each other to the nearest node

supporting external connectivity. A distributed system consisting of many

wireless mobile stations/ nodes with no predetermined topology or central control.

Each device has to manage and maintain known optimal paths which can change very often due to mobility.

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All the nodes in the network may be sub-divided into two categories:

• Client Node: • These may be the Mobile Nodes or the Forwarding Nodes that

are within the ad-hoc network.• Gateway Node:

• Nodes within the ad-hoc network but with external connectivity.

• Help in forwarding packets to some external network or the internet.

• Must have at least two interfaces – one for the ad-hoc network and the other connected to the internet

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Inte

rnet

Ad-hoc Mesh Network – an overviewHow it Works

Forwarding Node Gateway Node Mobile Node

Mobile Ad-hoc Mesh Network

Correspondent Node

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Advantages

Motivation and Practical Applications Implementation at Jadavpur University

Campus Looking ahead : Possible enhancements

Jadavpur University


Advantages

Dynamic Route Discovery and Route Maintenance

• no initial information about the routes from one node to another has to be provided.

• The nodes can dynamically determine the appropriate route to forward packet to the destination nodes.

• Character of mesh topology and ad-hoc routing promises greater stability in the face of changing conditions or failure at single nodes.

Adaptive Backbone provisioning• lack of the requirement to provide a wired backhaul connection to

every node.• user traffic is relayed using wireless radios between nodes, until it

reaches its destination.

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Advantages

Fault-tolerance• Adaptive to failure in nodes or drop-outs in radio coverage – traffic is

simply re-routed dynamically

Organization:• The decentralized nature of mesh networks lends itself well to a

decentralized ownership model.• Each participant in the network owns and maintains their own hardware,

which can greatly simplify the financial and community aspects of the system.

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Ad-hoc Mesh Network – an overview Advantages

Motivation and Practical Applications

Implementation at Jadavpur University Campus

Looking ahead : Possible enhancements

Jadavpur University


Motivation and Practical Applications

Interconnection amongst the Universities• Connecting the various universities and colleges to create a wireless corridor

that can be used for knowledge transfer and future research activities

Low cost connectivity to the rural areas• The vast uninhabited tracts of land in rural areas may be explored to extend

connectivity to rural areas or to far-off cities by providing intermediate hops.

Future test bed for network research• Although a great deal of research has been done on Ad Hoc routing protocols,

relatively little real-world evaluation has been carried out.• Most research published on the topic has been evaluated only in simulation.• While simulation can provide a great deal of information about many

properties of a routing algorithm, unfortunately many real-world effects on a protocol's performance cannot be predicted in simulation.

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Internet

Jadavpur University



Ad-hoc Mesh Network – an overview Advantages Motivation and Practical Applications

Implementation at Jadavpur University Campus


Jadavpur University


Implementation Details

Platform Used:• An easily deployable workstation that can support wireless interface(s) –

our implementation, we have used workstations with Intel Pentium 4 processors (x86 architecture) and Linux Fedora Core – I installed

Wireless interface and its driver:• D-Link g520+ PCI Adapter with open source driver

Implementation of AODV routing protocol:• Our implementation uses an AODV implementation from NIST that requires

NetFilter architecture.• Gateway feature included thereby providing external connectivity to the

nodes in the Ad-hoc network.

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Implementation Details Application Program for Monitoring:

A Client – Server application for monitoring the performance of the nodes in the network. It is a GUI based application developed in Java that provides a user friendly environment for the purpose of monitoring.

The Server Application• Acts much like a Daemon process that continually listens to a port

(2048) assigned to it.• On receiving a connection, the Server services it and delivers the client

the proper information according to the request received.

The Client Application• Provides a rough graphical representation of the present network

scenario.• Information can be gathered from any node in the network, provided

the server is running on the destination Node. • On requesting information about a particular node, the Client

application opens a connection with the Server running on the destination node, gathers information and displays it.

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Ad-hoc Mesh Network – an overview Advantages Motivation and Practical Applications Implementation at Jadavpur University

Campus


Jadavpur University


Looking ahead : Possible

enhancements Dynamic Host Configuration

• Our implementation uses static configuration of IP addresses.• In a truly dynamic real scenario, it would be ideal to dynamically obtain an

IP address that is valid & unique in the AODV subnet.• Use of Distributed and Dynamic Address Configuration in the network would

impart a truly dynamic nature to the network.

QoS over Ad-hoc Networks• 802.11b was not designed with providing QoS in mind, and it is not trivial to

provide QoS guarantees over such networks.• To bridge the gap, we envision to investigate the problem of providing QoS

guarantees in a small sized 802.11b ad hoc wireless network.

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Thank you

implementation of ad-hoc mesh network

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