A Ubiquitous Stable Storage for Mobile Computing Devices

1
A Ubiquitous Stable Storage for Mobile Computing
Devices

• March 18th, 2004
• M.S. Dae Wook Kim
• Computer Science and Grid Computing Lab.
• Yonsei University

2
Outline

• Introduction
• Motivation
• Proposal
• Architectural Framework
• Conclusion Future Work

3
Introduction

• The brief introduction of Research
• Distributed Systems Research Group at Howard
  Univ.
• Infrastructure of ubiquitous stable storage for
  mobile computing devices
• Based on wireless JINI technology

4
Motivation

• The event of a device related failure
• Smaller, faster, and more personalized computing
• ? the big gap between mobile device and desktop
  application.
• Catastrophic event
• - power lost
• - ease that device can be lost, misplaced,
  damaged
• Several risks in term of data reliability and
  dependability

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Motivation (Cont.)

• Current Technique for this problem
• Backup and synchronization of mobile data into
  desktop or server using a special docking device,
  or a low-bandwidth network connection
• The limitation of Current Technique
• Unpredictable the failure of mobile devices
• Current state of the device between syncs is loss

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Proposal (1)

• A networked non-volatile memory
• Stable storage for mobile devices
• Location aware network enabled service utilized
  by mobile computing such as network-enabled print
  or fax services

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Proposal (2)

• Backup protocol
• Guarantee delivery in transient link failure
• The security and privacy of mobile data
• Use shared key authentication
• Implemented within the Jini framework

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Architectural Framework(1)

• System Architecture
• Consist of six components
• Transmit wireless signals
• Initiate a service discovery to LDSL
• Monitor the network for the request of mobile
  device by LDSL

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Architectural Framework (Cont)

• System Architecture
• Detect a stable storage device (SSD) in LAN
• Local Directory Service Locator returns the
  location of SSD to mobile device
• Invoke the SSD directly store temporary
• Data is encrypted and forward to Destination
  Machine
• SSD as a temporary cache Ubiquitous!
  (universally located)

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Architectural Framework (Cont)

• Backup to Destination Machine

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Architectural Framework(2)

• Communication Transport
• Locate detect storage unit in LAN
• ? Require pervasive network access
• omni-directional transmission
• Bluetooth vs IR (Infra red)
• Diffused IR communication
• - IR PC card adapter inserted into PCMCIA of
  mobile device (MD)
• - Possible to communicate between MD and LAN via
  a antenna on
• IR base station

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Architectural Framework(3)

• Security and Privacy of Mobile Data
• Generally, wireless connectivity increase
  vulnerability to threats such as malicious
  attacks, monitoring, unauthorized system access
• In the system, no way to authenticate the mobile
  device before utilizing any services on the
  network
• No way to avoid theft of the storage device
• No way to authenticate the final destination
  machine before beginning a backup session.

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Architectural Framework (Cont)

• Trusted authentication encryption proxy
• Authenticate service locator storage devices
  by Mobile Device
• Specific protocol utilizing a shared secret key
• Provide DES mutual handshake

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Security System Architecture
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Architectural Framework(4)

• Backup Protocol
• Provide transparent delivery in transient link
  failure
• Implemented using TCP/IP socket on top of IrLAN
• Maintain status information for backup purpose
• - backup bit
• - creation time
• - modification time
• - the last backup time
• - message log

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Architectural Framework (Cont.)

• Two types of Backup Protocol
• Between mobile devices and stable storage devices
  
• Between ubiquitous storage devices and
  destination machine

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Architectural Framework (5)

• Protocol Between mobile devices and ubiquitous
  stable storage devices
• Execute in FIFO order based on modification
  times.
• Store fixed sized block into a stable storage
  device
• For each block,
• - message-id - backup bit for
  block
• - logical timestamp - total data size
• - identity of the bock

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Architectural Framework (Cont.)

• How does Backup Session start?
• ltStep1gt Backup Request to storage device
• ltStep2gt receive AWK(BREQ message) to
  a mobile device
• ltStep3gt Backup bit is set
• (otherwise, block is pending)
• ltStep4gt transmit data block
• ltStep5gt Backup process continues for all data
  block until EOT

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Architectural Framework (6)

• Protocol Between ubiquitous storage devices and
  destination machine
• Construct a summary vector for each backup
  session
• contains message ids of the transmitted data
  blocks
• Reconstruct database and application data in
  destination machine (No duplicates)

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Conclusion

• Communication and security issue between wireless
  mobile devices
• Backup protocol

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Future Work

• Protocol that will provide ubiquitous
  bidirectional synchronization
• Serve Storage devices as a gateway between mobile
  devices and primary machine

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Thank you so much!
Hi! Grid Family!