DDBS and P2P

1
DDBS and P2P JXTA JuxMem
2
DDBS vs P2P
3
Architecture Priniciples
4
Some research issues
5
JXTA a specification for P2P computing

• Open platform for P2P programming
• Common functionalities
• Language, OS, network
• Set of interoperable protocols (XML)?
• Open source project
• http//www.jxta.org

6
JXTA architecture
JXTA Applications
SunJXTA Applications
Community JXTA Applications
Sun JXTAServices
JXTA Shell
Community JXTA Services
JXTA Services

• Indexing
• Searching
• File sharing

Peer Commands
Peer Monitoring
Peer Groups
Peer Pipes
JXTA Core
Security
Security
Any Peer on the Expanded Web
7
JXTA virtual network
Project JXTA virtual network
Peer
Peer
Peer
Peer
Peer
Peer
Peer
Peer
Virtual mapping
TCP/IP

Physical network

NAT
HTTP
Firewall
Physical Network
8
JXTA protocols stack (2/2)?
Pipe Binding Protocol
Peer Discovery Protocol
Peer Info Protocol
Peer Resolver Protocol
Peer Rendezvous Protocol
Peer Endpoint Protocol
9
Peers

• A peer
• Unique identifier (UUID)?
• Adressable independently of its location
  (firewalls, NAT)?
• Multiple Peer endpoint address (TCP, HTTP,
  etc.)?
• Peer types
• Edge send/receive cache
• Rendezvous fwd requests
• Relay routing cache firewall support

10
Peer groups

• Why Peer Groups?
• Provide a group identity (common interest)
• Create secure protected domains
• Scope peer operations (discovery, search,
  communications)?
• Enable monitoring

NetPeerGroup
PeerGroupA
Peer ID
Peer ID
Peer ID
Peer ID
Peer ID
Peer ID
Peer ID
Peer ID
PeerGroupB
11
Advertisements

• Every resource is represented by an advertisement
• Peer
• Peer group
• Pipe
• Service
• Content
• Peer status

PeerGroup Advertisement lt?xml
version"1.0"?gt lt!DOCTYPE jxtaPGAgt ltjxtaPGAgt ltG
IDgt urnjxta uuid- BCBCDEABDBBBABEABBBABA
000000 lt/GIDgt ltMSIDgt urnjxtauuid- BFEFDEDFBA
BAFRUDBACE00000001 lt/MSIDgt ltNamegt My
Group lt/Namegt ltDescgt This group is to be used
for my own testing lt/Descgt lt/jxtaPGAgt
12
Network services

• Peer services peergroup services
• Implement protocols
• Service invocation
• Not specified by JXTA
• Can be dynamically loaded
• Code retrieved at run-time
• Applications
• Use several services

13
JXTA core standard protocols

• Core protocol
• Endpoint Routing Protocol
• Transport protocols used underneath (TCP, TLS,
  HTTP, etc)?
• Resolver protocol generic RPC
• Standard protocols
• Peer discovery protocol
• Discovering resources
• Rendezvous protocol
• Management of the JXTA network
• Peer Information protocol
• Pipe binding protocol
• Resolution of virtual channels (pipes)?

14
API of a service

• Init( Group, assignedID, ModuleImplAdvertisement
  )?
• startApp( args )?
• stopApp()?
• getImplAdvertisement()?
• getInterface()?
• specific API

15
Lookup mechanisms in P2P systems

• Peers have high churn rate
• Based on DHTs (Chord, Pastry, Tapestry, etc)?
• Efficient
• But costly to maintain a consistent distributed
  index
• Based on crawling (Gnutella, KaZaA, etc)
• Expensive
• But do not have any maintenance cost
• Hybrid approach loosely-consistent DHT

16
Organization of a JXTA overlay

• Type of peer involved
• Edge peer
• Rendezvous peer
• Concept of peer view (PV)?
• Ordered list of known rendezvous peers
• Peer view protocol for the discovery of other
• rendezvous peers
• Structured overlay
• Loosely-Consistent DHT between rendezvous peers
• Mechanism for ensuring convergence of the PV
  across rendezvous peers
• Key point for the efficient of the
  loosely-consistent DHT
• Fallback mechanism limited-range walker

17
Time for the PV to converge across rendezvous
peers?

• Testbed up to 580 nodes
• Rennes (161), Bordeaux (44), Orsay (185),
  Toulouse (50), Sophia (100) and Lyon (40)?
• Logical overlay
• n rendezvous peers (n 2, 10, 80, 160, 580)?
• No delay between startup
• Initial topology simple link between rendezvous
  peers
• Duration up to 2 hours

18
Conclusion JXTA technology today

• Enhanced network and J2SE platform
• Mature, stable, secure, scalable platform.
• 2.0 spec, code, demos, docs, and tutorials
  on-line
• Public virtual network in place
• Release 2.5.x
• JXTA-C and JXME implementations available
• JXTA-C better on some points than JXTA-J2SE
• JXTA-C 2.5.2 JXME 2.1.2
• Community projects industrial choice

19
JuxMem a grid data sharing service build using
P2P techniques
20
(No Transcript)
21
(No Transcript)
22
(No Transcript)
23
(No Transcript)
24
(No Transcript)
25
(No Transcript)
26
(No Transcript)
27
Idea an Hybrid Approach

• DSM systems consistency and transparent access
• P2P systems scalability and high dynamicity

28
Overview of JuxMems architecture

• Based on JXTA (Sun Microsystems), a generic
  framework for custom P2P services and
  applications
• Basic concepts peer, peer group, advertisement
• Specifies a set of protocols for inter-peer
  interaction

Juxmem group
Cluster group C
Cluster group A
Cluster group B
29
(No Transcript)
30
(No Transcript)
31
(No Transcript)
32
(No Transcript)
33
Managing Shared Data Blocks

• Allocate a memory block create a data group
• Data blocks replicated on providers
• Data blocks identified by the ID of the peer
  group
• Transparent access for clients via data ID
• Consistency
• Current model Entry Consitency
• Simultaneous updates of replicas (logical
  multicast)?
• Clients are not notified of updates

34
The big picture of JuxMem layers
3
?
2
1
35
The big picture of juk layers
Module mémoire (niveau haut)?
2
3
Module publication et découverte
Module mémoire (niveau bas)?
Module communication
Pipe service
Discovery service
Module service
1
Resolver service
Rendezvous service