Transcript 投影片 1
JXTA Protocol Introduction
Student : Jia-Hui Huang Adviser : Kai-Wei Ke Date : 2005/11/22
Outline
P2P Introduction JXTA Introduction JXTA Assumptions JXTA Concept JXTA Protocols JXTA Connection Scenario Demo Summary
P2P Introduction (1/2)
The term “ Peer-to-Peer ” refers to a class of system/networks that : Distributed resources Perform function in a decentralized manner Each node potentially has the same responsibility & capability.
Sharing can be in many ways : CPU Cycle : share workload Storage space : Napster, Gnutella, Freenet … etc
P2P Introduction (2/2)
Why attractive ? Scalability Reliability Client – Server Ex. FTP Peer-to-Peer Ex. Bit Torrent
Outline
P2P Introduction JXTA Introduction JXTA Assumptions JXTA Concept JXTA Protocols JXTA Connection Scenario Demo Summary
JXTA Introduction(1/3)
What is JXTA Protocol ?
Developed by Sun Microsystems, Inc. 2001 v 1.0
Provide the basic P2P infrastructure Each resource are published as advertisement Some characteristic of JXTA network Discover each other Self-organize into peer group Advertise and discover network resource Communicate with each other Monitor each other
JXTA Introduction(2/3)
JXTA Protocol are composed six Protocols the following six protocol cooperate with other, and form JXTA protocol Peer Resolver Protocol ( PRP ) Peer Discovery Protocol ( PDP ) Peer Information Protocol ( PIP ) Pipe Binding Protocol ( PBP ) Endpoint Routing Protocol ( ERP ) Rendezvous Protocol ( RVP )
JXTA Introduction(3/3)
Not all protocol are necessary JXTA core Protocol – required PRP ERP JXTA standard protocol – not required Remaining JXTA Protocols ( PDP …etc ) More standard protocol increase interoperability
Outline
P2P Introduction JXTA Introduction JXTA Assumptions JXTA Concept JXTA Protocols JXTA Connection Scenario Demo Summary
JXTA
Assumptions
(1/2)
Peer not assume run time environments and programming languages Peers may appear, disappear and migrate at any time Communication between two peers is uni directional at same time Data delivery is unreliable Protocol messages and advertisements are defined using XML messages
JXTA
Assumptions
(2/2)
Message is give up delivery if destination is not available Each peer must be a member of the Net PeerGroups Peers must be members of the same peer group in order to exchange messages The published content is not guarantee can be received from JXTA network
Outline
P2P Introduction JXTA Introduction JXTA Assumptions JXTA Concept JXTA Protocols JXTA Connection Scenario Demo Summary
JXTA Concept
(1/7)
Peers Any network device that implement JXTA Core Protocol Identify by a unique ID Distribute resources and services using advertisement mechanism May advertisement multiple network interface - endpoint PeerGroups A common set of peer self-organized into a peer group Identify by a unique PeerGroup ID Peer group provide a set of service
JXTA Concept (2/7)
Discovery service Used by member to discovery resources ( pipe ….etc ) Membership service Used by member to accept of reject new peer join request Access service Used to validate requests made by one peer to another Pipe service Manage and create pipe between different group members Monitoring service Allow peer monitor each other in same group
JXTA Concept (3/7)
Two level of network service Peer service Accessible only one the peer that is publishing the service Peer group service Running on multiple members of the peer group pipes A virtual communication channel for peer exchange message, many type of pipe can establish Two mode of pipe transfer Point to Point Pipe Propagate Pipe
JXTA Concept (4/7)
IDs Each JXTA resource has a unique ID to identify an entity These resource include Peers, PeerGroups, content, pipes, module classes/spec.
codats Combination of content and its associated JXTA ID
JXTA Concept (5/7)
Module Module indicates the “service” provided by peer or PeerGroup Module class Define the service type, have a unique id Module specification Define the service specification, have a unique id
JXTA Concept (6/7)
All resource on the JXTA network are publish as advertisement Peer advertisement Describe a peer ID, name and other resource Peer group advertisement Describe a peer group specific resource Module class advertisement Describe a particular module class id stand for what type service
JXTA Concept (7/7)
Module specification advertisement Describe what particular module spec. ID stand for which spec.
Module implementation advertisement Describe one of implementation of a specific spec. it also provide necessary parameter of use this implementation
Outline
P2P Introduction JXTA Introduction JXTA Assumptions JXTA Concept JXTA Protocols JXTA Connection Scenario Demo Summary
JXTA Protocols
Two types of JXTA Protocol JXTA Core Protocol – required JXTA Standard Protocol – optional
JXTA Core Protocol
Protocol is a set of message format (XML) that exchange between peers JXTA Core Specification define ： Peer Resolver Protocol Endpoint Routing Protocol
Peer resolver protocol (PRP)
Provide a resolution service, used to send query and receive response Each query and response is addressed with a handler Handler is a demultiplexing key that specifies how, by which higher-level protocol to be processed
Endpoint routing protocol (ERP)(1/3)
ERP is used for routing When a peer wants to issue a message, it process is as follows ： Peer lookup his local cache If exist route information then directly use If no exist route information then find available peer router for asking (send route resolver query message)
Endpoint routing protocol (ERP)(2/3)
When peer router receive a route query If it know route information it will return as an enumeration of hop If it don’t know then peer will asking other peer router until no peer router Finally, if no peer router knows then give up routing this message note ： routing information may obsolete at any hop Shared Resource Distributed Index (SRDI) Utilize the set of rendezvous peer as resource index to help message direction
Endpoint routing protocol (ERP)(3/3)
At each hop the peer will extra a peer id information in the message header use for Loop detect New route discovery Message is a basic unit of data exchange and the process is like packet in protocol stack
JXTA Standard Protocols
Rendezvous Protocol (RVP) Peer Discovery Protocol (PDP) Peer Information Protocol (PIP) Pipe Binding Protocol (PBP)
Rendezvous protocol (RVP) (1/3)
RVP is used to propagate message within a peer group A peergroup may contains more than one rendezvous peer.
The set of rendezvous peer perform a peer view The PeerView is a list of the peers which are currently acting as Rendezvous Peers.
The RVP can divided into three parts Management protocol (peer view protocol) An optional protocol used by Rendezvous Peers to organize themselves Each Rendezvous Peer maintains its own local list of active PeerView members Rendezvous Peer exchange message with each other
Rendezvous protocol (RVP)(2/3)
Connection registration protocol (rendezvous lease protocol) An optional protocol enables non-Rendezvous Peers to subscribe to receive propagated messages. ( act as a rendezvous peer ) Leases are of fixed duration.
Rendezvous Peers offer lease its ability to distribute message.
Both rendezvous peer and subscriber can terminate the lease at any time.
Rendezvous protocol (RVP) (3/3)
Propagated message (rendezvous propagation protocol) A required protocol, enable peers to manage the propagation of individual message.
Propagation stop condition ： Loop/Duplicate ( detected by unique id ) TTL Rendezvous advertisement is used for describe a peer become a rendezvous peer
Peer discovery protocol (PDP) (1/2)
PDP is used to discover resource within a group Discovery peers behavior Use the field attribute and threshold to match query PDP message is not guarantee response
Peer discovery protocol (PDP)(2/2)
Five Scenario of discovery
Local Discovery Using Rendezvous Peer w/o Propagation Using Rendezvous Peer over Firewall Using Rendezvous Peer and Propagation
Peer information protocol (PIP)
An optional protocol, Used to obtain a peer status information.
No guarantee response.
Information include : Timestamp Traffic LastInCommingMessageAt LastOutgoingAt … etc SourcePid TargetPid … etc
Pipe binding protocol (PBP)
PBP is used to create a pipe between two peer (virtual communication channel) The underlying transport can use JXTA HTTP, JXTA TCP/IP or secure JXTA TLS Transport The pipe can viewed as a message queue that support create, bind, close, delete, send, and receive operation
Pipe advertisement
Used to describe a local binded pipe information Each advertisement has a pipe type field Currently three type has defined JXTAUnicast Unicast, unsecure, unreliable pipe.
JXTAUnicastSecure Unicast, secure ( using TLS ) pipe.
JXTAPropagate Diffusion pipes Diffusion pipes, used to send one-to-many messages.
Outline
P2P Introduction JXTA Introduction JXTA Assumptions JXTA Concept JXTA Protocols JXTA Connection Scenario Demo Summary
JXTA message transports
Three Scenario of message transports Communication across Firewall (outside to inside) Message to Peer across one Firewall (inside to outside ) Message to Peer across two Firewalls
Outline
P2P Introduction JXTA Introduction JXTA Assumptions JXTA Concept JXTA Protocols JXTA Connection Scenario Demo Summary
Demo
Messaging P2PAVConference File sharing Peer1 Peer2
Outline
P2P Introduction JXTA Introduction JXTA Assumptions JXTA Concept JXTA Protocols JXTA Connection Scenario Demo Summary
Summary
Project JXTA establish a virtual network overlay on top of existing networks.
JXTA provide a P2P systems, it achieve : Interoperability Platform independence Ubiquity It allow application developers build P2P application without take underlying network into account.
P2P system become more easy to develop.
Reference
Sun Microsystems Inc. “ JXTA v2.0 Protocols Specification ”, 2004 Li Gong Sun Microsystems, Inc “ Project JXTA : A Technology Overview ”, October 29 2002 Bernard Traversat, Ahkil Arora, Mohamed Abdelaziz, Mike Duigou, Carl Haywood, Jean Christophe Hugly, Eric Pouyoul, Bill Yeager, “ Project JXTA 2.0 Super-Peer Virtual Network ”, May 25 2003 www.jxta.org
Discovery Scenario (1/5)
lookup
communicate
Discovery Scenario (2/5)
multicast response
Discovery Scenario (3/5)
Response message Discovery message
Discovery Scenario (4/5)
response cache discovery
Discovery Scenario (5/5)
Connection Scenario (1/3)
By Propagate message Msg queue HTTP connection
Connection Scenario (2/3)
Regular connection
Connection Scenario (3/3)
message HTTP HTTP