Peer-to-peer networks

Exploits diverse connectivity between participants in a network.

Exploits the cumulative bandwidth of network participants.

Typically used for connecting nodes via large ad-hoc connections.

• Sharing content files containing audio, video, and data.

• Even real-time data, such as telephony traffic, is also passed using P2P technology.

Pure peer-to-peer network.

• There is no notion of clients or servers.

• Equal peer nodes that simultaneously work as both "clients" and "servers" to the other nodes on the network.

The Web Model

Contact a server and download a web page.

The server has all the resources and capabilities.

The P2P Model

A peer’s resources are similar to the resources of the other participants.

P2P – peers communicating directly with other peers and sharing resources.

P2P services.

• Distributed Computing.

• File Sharing.

• Collaboration.

Advantages

Clients provide resources, including bandwidth, storage space, and computing power.

As nodes arrive and demand on the system increases, the total capacity of the system also increases.

Distributed nature also increases robustness in case of failures by replicating data over multiple peers.

• Enable peers to find the data without relying on a centralized index server.

Applications

• File sharing

  • Using application layer protocols.

    • DirectConnect (centralized), Gnutella (flooding), BitTorrent (hybrid)

• VoIP

  • Using application layer protocols.

    • SIP

• Streaming media.

• Instant messaging.

• Software publication and distribution.

• Media publication and distribution.

• Radio, video.

Challenges

Peer discovery and group management.

Data location, searching, and placement.

• Search and routing.

Reliable and efficient file delivery.

Security/privacy/anonymity/trust.