Multi-Party XML Synchronization over Limited Bandwidth

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Multi-Party XML Synchronization over Limited
Bandwidth

• Thomas Wilczak
• Prof. James Riely

SE 696 Research Project Initial Presentation 5th
May, 2004
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Motivating Examples

• Distributed Inventory Management
• Central inventory stored as XML database
• Updates performed by employees using mobile
  devices while verifying actual product details

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Motivating Examples

• Distributed Inventory Management
• Characteristics
• Central data tree
• Segmentation of data
• Independent updates

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Motivating Examples

• Field Reconnaissance
• Central XML database containing information about
  field conditions
• Clients require current information about field
  conditions
• Clients performing updates to allow real-time
  decision-making

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Motivating Examples

• Field Reconnaissance
• Characteristics
• Clients require rapid access to most recent
  updates
• Central data tree needs coherent updates from
  clients

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General Problem Tree Synchronization

• Current Approaches
• Synchronization
• File Synchronization - rsync
• Source Synchronization - CVS
• XML Merge - Delta XML
• Abstraction
• Bi-Directional Language for Tree Transformation -
  Lenses

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Requirements

• Central data server
• Tree Structured data
• Clients running on limited devices
• Read access to data through clients
• Write access to tree subsets
• Handling transactions between clients and server
  smoothly and concurrently

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Synchronization Model Components

1. Abstraction Model responsible for moving data
   set from the server to the clients
2. Server side exclusion mechanism Prevents
   write-write conflicts when updates are sent from
   the client to the server
3. Client side command logging modifications made
   to the clients data recorded
4. Abstract series of commands sent back to server.
   Subset updated, synchronization performed

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Deliverables

• Simulation of Client and Server running in single
  JVM
• Server
• Handles reading, storing, and abstraction of data
  for use by clients.
• Maintains consistency of data by preventing
  conflicts.
• Reconcile Data changes as they are returned from
  the client.
• Client
• GUI allowing user to read and modify local data
  subset
• Logs abstract commands performed on local subset
• Proof of correctness (?) - possibilty for
  publication

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Project Outline Milestones

• Phase 1 Literature Review 11/2003 - 1/2004
• "What is a File Synchronizer?", S.
  Balasubrmaniam, B.C. Pierce
• "A Language For Bi-Directional Tree
  Transformations", Michael B. Greenwald, et al.
• SyncML Sync Protocol, version 1.1, SyncML Group
• Merging XML Changes with DeltaXML, Monsell EDM
  Ltd
• Phase 2 Project Definition 1/2004 - 3/2004
• Discussion and review of previous work
• Specification of approach and research objectives
• Initial implementation of Synchronization
  Infrastructure in ML
• Translation of initial implementation into Java
• Phase 3 Initial Presentation 5/7/2004
• Phase 5 Ongoing Development 5/2004 - 9/2004
• Phase 6 Intermediate Presentation 9/2004
• Completion 11/2004

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References

• "What is a File Synchronizer?", S.
  Balasubrmaniam, B.C. Pierce
• "A Language For Bi-Directional Tree
  Transformations", Michael B. Greenwald, et al.
• SyncML Sync Protocol, version 1.1, SyncML Group
• Merging XML Changes with DeltaXML, Monsell EDM
  Ltd