a d - hoc mobile application submitted by: artem barger itai gannon tatiana shvartzman

AD-HOC MOBILE APPLICATION

Submitted by:Artem BargerItai GannonTatiana Shvartzman

BACKGROUND AND PROJECT GOALS

• Currently in most social networks users identity is persisted and managed by service providers, like in the most popular examples: facebook and twitter.

• While we can think of another possible option – an Ad Hoc Social Networking, where user identity is not managed at all and created upon demand.

• Seem very natural to leverage MANET technology to implement self-configuring network of mobile devices connected by wireless links (peer-to-peer model), which will simulate and manage the Ad Hoc Social Network.

DESIGN

We assume our network topology is a star –

Two kinds of entities: Client – a device that runs only as an end user,

meaning connecting to an existing network (getting an IP from it) and starting the social interactions.

• Leader – is a client as far as the user is concerned, but behind the scene is also the network manager and is responsible for the following tasks:

allocating IP addresses updating all clients about connecting and disconnecting

of other clients managing all communication between clients (request

for user details, chat message, etc.)

Leader

Client Client

Client

ClientClient

DESIGN CONT.

ImageManager

Network

Ad-hoc connectivity

DHCPCommunication

Activities ~ GUI

ActivityLogin

ActivityChatActivityCreateUser

ActivityFileBrowser

ActivityUserDetails

ActivityUsersList

Messages

ALGORITHMS Updating online users:

Using a polling algorithm (ping-pong) between the leader and the client. The leader sends a ping message and the client answers with a pong message

– if too much time passes without the leader getting a ping from a client, he updates all connected clients with a broadcast that that client has disconnected.

Leader selection: Was solved by picking up as a leader the first node which managed to startup

and initialize the DHCP server.

Losing the leader of the network This happens in one of two cases :

The leader logs out. The leader gets out of range from the other users, so they don’t get a

ping message from him. When this happens, each client starts re-establishing the network as follows:

Check if his IP is the smallest one: If so - try to reconnect as leader. Otherwise – try to reconnect as client. If failed, the smallest IP has

not connected and will be considered as disconnected and the process will start again.