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Jgroups - Toolkit for Reliable Multicast Communication

Irfan Aris Nurhakim
Irfan Aris Nurhakim

JGroups is a toolkit for reliable multicast communication that provides protocols for message fragmentation, retransmission, ordering, and group membership changes. It operates at a lower level than multicast by providing a channel abstraction similar to sockets. Applications can then use higher-level building blocks composed of basic multicast functions. JGroups uses a flexible protocol stack that can be customized with different transport, discovery, reliability, and other protocols to meet an application's needs.

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JGROUPS AToolkit for Reliable Multicast Communication Wednesday, April 24, 13
Introduction API and Architecture Protocols Building Blocks Group Membership Conclusion OVERVIEW Wednesday, April 24, 13
INTRODUCTION What is JGroups? Toolkit for Reliable Multicast Communication Fragmentation Message retransmission Ordering Group membership, membership change noti鍖cation, etc. LAN or WAN based Wednesday, April 24, 13
INTRODUCTION Where JGroups 鍖ts in? Unreliable Reliable Unicast UDP TCP Multicast IP Multicast JGroups Wednesday, April 24, 13
API & ARCHITECTURE Wednesday, April 24, 13
CHANNEL Lower-Level Abstraction to build Multicast Communication Apps provided by JGroups. Similar to socket from Java Operations : Create a channel with a set of properties Connect to a group X. Everyone that connects to X will see each other Send a message to all members of X Wednesday, April 24, 13
BUILDING BLOCKS Group communication pattern Layered on top of channels More sophisticated APIs Applications communicate directly with the building block, rather than the channel. Composed with many basic multicast function Wednesday, April 24, 13
BUILDING BLOCKS Wednesday, April 24, 13
FLEXIBLE PROTOCOL STACK The most powerful feature of JGroups!! Contains a number of protocol layers in a bidirectional list. A message sent by Channel is simply passed to the protocol stack which in turn forwards it to the top most layer. Available Protocol : Transport: UDP,TCP,TCP_NIO,TUNNEL, JMS, LOOPBACK Discovery: PING,TCPPING,TCPGOSSIP, UDPPING Reliable delivery & FIFO: NAKACK, SMACK Group membership, Failure Detector, Security, Fragmentation,Virtual Synchrony, Ordering, etc. Wednesday, April 24, 13
GROUP MEMBERSHIP SERVICE Task : Maintain a list of members Notify members when a new member joins, or an existing member leaves (or crashes) Each member has the same ordered list List can be retrieved by Channel.getView() First (= oldest) member is coordinator If coord crashes, 2nd oldest takes over Wednesday, April 24, 13
VIRTUAL SYNCHRONY AView is a list of members (A,B,C,D) When members join/leave, a new view will be installed (A,C,D) Every healthy member receives the same set of messages between subsequent views Messages sent inV1 are received inV1 All msgs by sender received in same order Wednesday, April 24, 13
VIRTUAL SYNCHRONY The FLUSH protocol ensures that all members have received all msgs inV1 before installingV2 New members wont receive messages from previous views Member that left wont receive msgs Wednesday, April 24, 13
FAILURE DETECTION Failure detection protocol sends up SUSPECT event VERIFY_SUSPECT double checks GMS multicasts new view (not containing crashed member) If member resurfaces, it will be shunned Has to leave and rejoin group Wednesday, April 24, 13
FAILURE DETECTION Task : Detect if a member has crashed and send SUSPECT event up the stack (to be handled by GMS) Logical ring over membership Each member pings its neighbor to the right Wednesday, April 24, 13
FAILURE DETECTION Wednesday, April 24, 13
CONCLUSION Jgroups merupakan toolkit yang bisa dipakai saat akan membangun suatu aplikasi yang membutuhkan aspek reliability dalam komunikasi grup. Jgroups sangat modular dan mudah untuk dimodi鍖kasi sesuai dengan kebutuhan aplikasi Pengembang aplikasi bisa lebih fokus terhadap persoalan apa yang mau dipecahkan oleh aplikasinya. Wednesday, April 24, 13
REFERENCE JavaGroups - Group Communication Patterns in Java, Bela Ban. 1998 Design and Implementation of a Reliable Group CommunicationToolkit for Java, Bela Ban, - JgroupTutorial and Programmers Manual,Albert M. dkk. 2002. Reliable and Secure Distributed Programming 2nd Ed, C. Cachin dkk. 2011. http://www.jgroups.org https://github.com/belaban/JGroups Wednesday, April 24, 13
Thank you & Question? Wednesday, April 24, 13

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Jgroups - Toolkit for Reliable Multicast Communication

  • 1. JGROUPS AToolkit for Reliable Multicast Communication Wednesday, April 24, 13
  • 2. Introduction API and Architecture Protocols Building Blocks Group Membership Conclusion OVERVIEW Wednesday, April 24, 13
  • 3. INTRODUCTION What is JGroups? Toolkit for Reliable Multicast Communication Fragmentation Message retransmission Ordering Group membership, membership change noti鍖cation, etc. LAN or WAN based Wednesday, April 24, 13
  • 4. INTRODUCTION Where JGroups 鍖ts in? Unreliable Reliable Unicast UDP TCP Multicast IP Multicast JGroups Wednesday, April 24, 13
  • 6. CHANNEL Lower-Level Abstraction to build Multicast Communication Apps provided by JGroups. Similar to socket from Java Operations : Create a channel with a set of properties Connect to a group X. Everyone that connects to X will see each other Send a message to all members of X Wednesday, April 24, 13
  • 7. BUILDING BLOCKS Group communication pattern Layered on top of channels More sophisticated APIs Applications communicate directly with the building block, rather than the channel. Composed with many basic multicast function Wednesday, April 24, 13
  • 9. FLEXIBLE PROTOCOL STACK The most powerful feature of JGroups!! Contains a number of protocol layers in a bidirectional list. A message sent by Channel is simply passed to the protocol stack which in turn forwards it to the top most layer. Available Protocol : Transport: UDP,TCP,TCP_NIO,TUNNEL, JMS, LOOPBACK Discovery: PING,TCPPING,TCPGOSSIP, UDPPING Reliable delivery & FIFO: NAKACK, SMACK Group membership, Failure Detector, Security, Fragmentation,Virtual Synchrony, Ordering, etc. Wednesday, April 24, 13
  • 10. GROUP MEMBERSHIP SERVICE Task : Maintain a list of members Notify members when a new member joins, or an existing member leaves (or crashes) Each member has the same ordered list List can be retrieved by Channel.getView() First (= oldest) member is coordinator If coord crashes, 2nd oldest takes over Wednesday, April 24, 13
  • 11. VIRTUAL SYNCHRONY AView is a list of members (A,B,C,D) When members join/leave, a new view will be installed (A,C,D) Every healthy member receives the same set of messages between subsequent views Messages sent inV1 are received inV1 All msgs by sender received in same order Wednesday, April 24, 13
  • 12. VIRTUAL SYNCHRONY The FLUSH protocol ensures that all members have received all msgs inV1 before installingV2 New members wont receive messages from previous views Member that left wont receive msgs Wednesday, April 24, 13
  • 13. FAILURE DETECTION Failure detection protocol sends up SUSPECT event VERIFY_SUSPECT double checks GMS multicasts new view (not containing crashed member) If member resurfaces, it will be shunned Has to leave and rejoin group Wednesday, April 24, 13
  • 14. FAILURE DETECTION Task : Detect if a member has crashed and send SUSPECT event up the stack (to be handled by GMS) Logical ring over membership Each member pings its neighbor to the right Wednesday, April 24, 13
  • 16. CONCLUSION Jgroups merupakan toolkit yang bisa dipakai saat akan membangun suatu aplikasi yang membutuhkan aspek reliability dalam komunikasi grup. Jgroups sangat modular dan mudah untuk dimodi鍖kasi sesuai dengan kebutuhan aplikasi Pengembang aplikasi bisa lebih fokus terhadap persoalan apa yang mau dipecahkan oleh aplikasinya. Wednesday, April 24, 13
  • 17. REFERENCE JavaGroups - Group Communication Patterns in Java, Bela Ban. 1998 Design and Implementation of a Reliable Group CommunicationToolkit for Java, Bela Ban, - JgroupTutorial and Programmers Manual,Albert M. dkk. 2002. Reliable and Secure Distributed Programming 2nd Ed, C. Cachin dkk. 2011. http://www.jgroups.org https://github.com/belaban/JGroups Wednesday, April 24, 13