1. Peer to Peer Discovery Nate Thrasher

2. Peer to Peer Discovery ● 2 Basic Categories – Hardware Discovery – Information Discovery ● JXTA (http://www.jxta.org) has 6 protocolshttp://www.jxta.org – http://spec.jxta.org/nonav/v1.0/docbook/JXTAProtocols.html http://spec.jxta.org/nonav/v1.0/docbook/JXTAProtocols.html – ERP (Endpoint Routing Protocol)

3. Peer to Peer Discovery ● Hardware Discovery – Discovery of nodes in local network – Discovery of nodes outside of local network (through firewalls/proxies) ● Information Discovery – Advertise local, discoverable information. – Submit a query to any node and have it propagate throughout the “peer network” and return a result.

4. Peer to Peer Discovery ● Hardware Discovery – Multicast Communication ● Used for LAN discovery ● Used by all nodes in P2P network – HTTP Communication ● Used for discovery outside of LAN ● Performed by special “Router” node

5. Peer to Peer Discovery ● Multicast Communication – Packets exchanged on multicast group containing IP/port available for direct connection. ● Router nodes store these for reference when external router nodes ask to send a packet to a local node. ● Every node on a local network should maintain a list of every other node.

6. Peer to Peer Discovery ● HTTP Communication – Used by router nodes to communicate through a firewall/proxy. ● Messages are wrapped in an http packet and sent through the firewall (assuming it allows http communication on a standard port). ● HTTP packets are automatically routed to the client from which the request was made. ● The packet contains information that tells the router node where it needs to be sent.

7. Peer to Peer Discovery ● Hardware Discovery NODE ROUTER NODE Firewall ROUTER NODE Multicast HTTP

8. Peer to Peer Discovery ● My Implementation – Multicast Only ● Areas for Improvement – Add HTTP – Add some kind of Information discovery