1 / 12

Peer-to-Peer Overlay Networks in an Event-Based Middleware

Peer-to-Peer Overlay Networks in an Event-Based Middleware. DEBS’03, San Diego, CA, USA, June 2003. Overlay Broker Networks. Distributed pub/sub systems Mapping of brokers to physical nodes Specification of overlay topology Efficiency, reliability, manageability, …. Today

cato
Download Presentation

Peer-to-Peer Overlay Networks in an Event-Based Middleware

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Peer-to-Peer Overlay Networks in an Event-Based Middleware DEBS’03, San Diego, CA, USA, June 2003

  2. Overlay Broker Networks • Distributed pub/sub systems • Mapping of brokers to physical nodes • Specification of overlay topology • Efficiency, reliability, manageability, … Today • Static neighbour lists • Difficult at deployment time • Require global view • Depend on physical network topology • Hierarchical topologies • Hard to maintain global properties • No redundancy Tomorrow • Self-managing overlays • Add more brokers on demand • Not only useful for large-scale • Adaptive overlay networks • Reflect current network situation • Lead to more efficient event dissemination • Evaluation

  3. Overview • Overlay Broker Networks • Peer-to-Peer Techniques • Hermes • Type- and Attribute-Based Routing • Simulational Evaluation • Routing Efficiency • Space Efficiency and Distribution • Message Complexity • Conclusions

  4. Peer-to-Peer Techniques • Distributed hash tables (Pastry, CAN, Chord, …) • Overlay network of nodes with unique ids • Hash operation from key to nodeid • Scalable and efficient • Locality properties • Advantages of P2P for publish/subscribe • Higher abstraction for building pub/sub systems • Content-based routing algorithm deals with hash keys • P2P overlay handles neighbouring set for event brokers route (msg, key)

  5. R B B B B B B P P P P S S P P P P S S S S Hermes • Hermes, an event-based middleware • P2P overlay network • Evaluation of its efficiency vs. Siena-like approach • Type- and attribute-based publish/subscribe • Event Clients • Event Brokers • Local Broker, Rendezvous Node • Rendezvous Nodes • Set up on a per type basis • Hash of event type name gives key for DHT • Ensure that advertisements and subscriptions join in the network

  6. Type- and Attribute-Based Routing Advertisement Messages • Routed towards RN by publishers • Create entries in advertisement routing tables along the way Subscription Messages • Routed towards RN by subscribers • Follow the reverse path of advertisements • Create entries in subscription routing tables along the way Publication Messages • Follow the reverse path of subscriptions • Get filtered along the way

  7. Simulational Evaluation • Evaluation of content-based pub/sub in simulator • Large-scale deployment for experiments difficult • Realistic network topologies and model for simulation • E.g. notification latency, hop count, routing cost, … • Scale reflects corporate deployment (102 event brokers) • Keep number of subscribers small if routing unaffected DSSim • Discrete event simulator • Transit stub network model • Visualisation plug-ins Pan • Pastry-like routing CovAdv • Siena-like pub/sub • Static set of neighbours • Acyclic topology Hermes • Pub/sub

  8. Routing Efficiency • Overlay networks used in experiments • Hermes: Sequential addition to closest existing broker w.r.t latency • CovAdv: Pre-computed minimum spanning tree Latency per notification (500 brokers; single subscriber per broker) • Quality of the overlay • Decreases  tree is more populated • CovAdv (closest broker) has worst latency • CovAdv (min span) is optimal • Hermes is in between

  9. Space Efficiency and Distribution Routing table sizes • Hermes does not broadcast advertisements • Hermes has slightly less subscription state due to better routing • Converge to same value as tables become full Routing table distribution • CovAdv: Majority of broker has 20 routing table entries • Hermes: No broker has more than 15; some have none

  10. Message Complexity Message numbers (Advs, Subs, Pubs) (100 event types) • Hermes sends fewer publications than CovAdv due to its better routing • Hermes sends moresubscriptions than CovAdv due to RNs • Number of advertisements staysconstant

  11. Conclusions • Self-managing & adaptive overlay networks are needed • Distributed Hash Tables are helpful • Evaluation through simulation • Contrast different kinds of pub/sub approaches • Peer-to-peer routing with RNs is efficient • Future Work • Fault-tolerance • Dynamic network environments

  12. Thank You Any Questions?

More Related