Transcript JXTA
JXTA Selo TE 2005 Introduction What is JXTA (pronounced Juxta) Jxta – an open, network computing platform designed for peer-to-peer (P2P) computing Provides a base P2P infrastructure over which other P2P applications can be built Originally conceived by Sun Microsystems Designed with the participation of experts from academia and industry Jxta P2P Software Architecture Jxta Three Layer Cake JXTA applications JXTA services JXTA core Jxta community applications Jxta community services Peer groups Sun Jxta applications Sun Jxta -indexing Services – searching Peer pipes Peer Shell --------Peer commands Peer monioring Security Any peer on the extended Web Jxta Layers Platform - Minimal and essential primitives Services - Network / Web services Peer & peer group discovery Communication Monitoring Security Indexing,searching Directory storage systems Distributed file systems Applications Instant messaging Content management Distributed auction systems P2P email systems Jxta Jargon Peers Peer groups Collection of peers with common set of interests Unique PeerGroup Id Default: World Peer Group Messages Message-based communication XML Datagram Envelope having header, digest, source & destination endpoints Pipes Virtual communication channels Network abstraction over the peer endpoint transport Jxta Jargon (contd) Services Peer Services PeerGroup Services Discovery service Membership service Access service Pipe service Resolver service Monitoring service Codats (Code/Data) Identifiers Advertisements Jxta Protocols PeerGroup Peer Peer Membership Protocol PeerGroup Peer Information Protocol Peer Information Protocol Peer Binding Protocol Peer Binding Protocol Peer Discovery Protocol Peer Discovery Protocol Peer Peer Resolver Protocol Resolver Endpoint Peer Membership Protocol Peer Resolver Protocol Resolver Peer Endpoint Protocol Transport Endpoint Peer Endpoint Protocol Transport Jxta Protocols Set of six protocols Designed for ad hoc, pervasive and multi-hop peer-to-peer network computing Objectives Interoperability Plaform independence Ubiquity Using the protocols, peers can cooperate to form self organized and self-configured peer groups Advertise resources Discover network resources Route messages/communicate Peer Discovery Protocol Enables peers to discover peer resources Peers, peer groups, pipes, services, etc Default discovery protocol Based on web-crawling and rendezvous peers Rendezvous peers Cache advertisements Forward requests Discovery Request messages Unicast propagate Peer Resolver Protocol Enables a peer to send a generic query to another peer service Each service can register a handle in peergroup resolver Unique service handler name A peer is not required to respond to a ResolverQuery request Peer Membership Protocol Peers use PMP for joining and leaving peer groups Actions: Apply Join Renew Cancel Authenticators and security credentials to provide desired level of protection Peer Information Protocol PIP allows a peer to learn about the capabilities and status of other peers Eg. Ping a peer to determine if it is alive PeerInfo Messages <?xml? Version=“1.0” encoding=“UTF-”> <jxta: PeerInfo> <Credential> Credential </Credential> <SourcePid> Source Peer Id </SourcePid> <TargetPid> Target Peer Id </TargetPid> <Uptime> uptime </uptime> <Timestamp> timestamp </timestamp> <PeerAdv> Peer advertisement </PeerAdv> </jxta: PeerInfo> Peer Binding Protocol PBP is used by peers to bind a pipe advertisement to a pipe endpoint Pipes can be viewed as abstract named message queues Support abstract operations Bind Unbind Peer Endpoint Protocol Also called Endpoint Routing Protocol Allows peers to query a peer router for available routes for sending a message to a destination peer Router peers Cache route information Bridge different logical and physical networks Jxta Java Binding Jxta reference implementation in Java (JDK release 1.1.4) Portability Ease of development Rich set of class libraries XML Messages and advertisements Parsing and extensibility Lightweight XML parser that supports a subset of SML - MicroXML Jxta Class organization Two main class hierarchies: net.jxta.*classes Interfaces for Jxta protocols and core building blocks net.jxta.impl.*classes Interfaces’ implementations Peer class • Boot class – net.jxta.impl.peergroup.Boot Peer Group • PeerGroup class – net.jxta.peergroup.PeerGroup Applications • net.jxta.platform.Application Security Crypto Library Hashing functions (MD5) Symmetric encryption (RC4) Asymmetric encryption (DH and RSA) Pluggable Authentication Module (PAM) Password based login scheme Transport security mechanism Simple access-control mechanism NAT/Firewalls – active research Jxta Shell Application built on top of Jxta Platform Networked command-line interface Shell commands (similar to Unix) Man Env Whoami Peers Importfile Mkpipe Applications Jxta Content Manager Service (CMS) InstantP2P Allows sharing and retrieving of content Peer-to-peer messenger service Group chat File sharing Net Services standards such as WSDL,ebXML,SOAP,UPnP,etc Conclusion Foundation for peer-to-peer systems Protocol suite – technology independent of APIs Independent of transport protocols Heterogeneous devices with completely different software stacks can interoperate through Jxta protocols Implementation over TCP/IP, HTTP, Bluetooth, HomePNA, etc Jxta promise !!