Types

Pure P2P

Refers to an environment where all the participating nodes are peers.

• No central system controls, coordinates, or facilitates the exchanges among peers.

Hybrid P2P

Refers to an environment where there are servers which enable peers to interact with each other.

• The degree of central system involvement varies with the application.

• Different peers may have different functions (simple nodes, routers, rendezvous).

No method is better than the other, each has its advantages and its drawbacks, each is the right choice for some applications.

Simple Peers

Single end user, allowing that user to provide services from his device and consuming services provided by other peers on the network.

• Will usually be located behind a firewall, separated from the network at large; peers outside the firewall will probably not be capable of directly communicating with the simple peer located inside the firewall.

• Because of their limited network accessibility, simple peers have the least amount of responsibility in any P2P network.

They are not responsible for handling communication on behalf of other peers or serving third-party information for consumption by other peers.

Rendez-vous Peers

Gathering or meeting place.

• Provides peers with a network location to use to discover other peers and peer resources.

Peers issue discovery queries to a rendez-vous peer, and the rendez- vous provides information on the peers it is aware of on the network.

May cache information on peers for future use or by forwarding discovery requests to other rendez-vous peers.

• Improve responsiveness, reduce network traffic, and provide better service to simple peers.

Usually outside a private internal network’s firewall. A rendez-vous could exist behind the firewall, but it would need to be capable of traversing the firewall using either a protocol authorized by the firewall or a router peer outside the firewall.

Router (Relay) Peers

A router peer provides a mechanism for peers to communicate with other peers separated from the network by firewall or Network Address Translation (NAT) equipment.

Peers outside the firewall to communicate with a peer behind the firewall, and vice versa.

A relay is not necessarily a rendez-vouz peer.

• Relay is on the data stream.

• Rendez-vous is always on the discovery path (and maybe in the data stream).