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Supporting Groupware in Mobile Networks

Supporting Groupware in Mobile Networks. Idit Keidar, Technion – I.I.T. Joint work with N. Lavi and I. Cidon. Agenda. Motivation for mobile groupware Current solutions Our proposed architecture Group management- one solution Simulation and analysis Future work Conclusions.

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Supporting Groupware in Mobile Networks

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  1. Supporting Groupware in Mobile Networks Idit Keidar, Technion – I.I.T Joint work with N. Lavi and I. Cidon

  2. Agenda • Motivation for mobile groupware • Current solutions • Our proposed architecture • Group management- one solution • Simulation and analysis • Future work • Conclusions

  3. Current Application Trends • Groupware and collaborative applications are widely used. • Chat, Instant-Messaging, VoIP, VCoIP, Net-meeting • Exchange, Lotus notes, webex • Multiplayer interactive games • Push-to-talk (PTT)

  4. Current Cellular Trends • Simple groupware such as Instant Messaging widely used • Major cellular providers (Orange, Verizon, Nextel) offer PTT services • The Yankee Group (Sep. 2003): • In 2003, $84 million PTT revenue, 2.3 million PTT subscribers • By 2008, $10.1 billion PTT revenue, 340 million PTT subscribers

  5. Future Cellular Trends • Richer groupware applications • Data+ voice+ video • Adopting TCP/IP infrastructure • Session Initiation Protocol (SIP) signaling • OMA, 3GPP, 3GPP2 standards

  6. Wireless Networks Trends • Maturing standards (Wi-Fi, WiMAX) • High availability of hot spots • Supported in PDAs, Pocket PCs, laptops, and cellular-phones • Emerging standards and working groups: IETF-MIP, Open Mobile Alliance, 4G

  7. Mobile Networks Trend Groupware popularity Wireless access availability Cellular going IP + + B3G Convergence

  8. The Future Network • IP based

  9. Mobile Groupware Design Goals • Mapping group names to subscribers • Mobility support • Seamless handoff • QoS support for RT applications • Transport efficiency • Transport reliability • Roaming, AAA • Scalable • Support for incremental deployment

  10. Previous Solutions: Mobile IP • RFC 3344 • The standard for seamless mobility • Unicast sessions only • Dependence on a single home • Triangle routing • Poor performance and lack of QoS support • Inadequate for RT applications • Route optimization to 3344 • Eliminate triangle routing • Difficult to deploy • Unclear if it can support simultaneous movements

  11. Previous Solutions: Cellular • OMA PoC working group (cellular operators) • Single server architecture • Large overhead • Triangle routing

  12. Our Proposed Solution Mobility and Group Management Architecture [Lavi, Cidon, Keidar MWCN 2004]

  13. MaGMA’s Architecture • Consists of Mobile-Group Managers (MGMs) and Mobile Nodes (MNs) • Version 1: MGMs static and well-known • MGM in charge of one or more domains • Entering a new domain, MNs obtain IP addresses and contact local MGMs

  14. Example: MaGMA Groups Group Blue Group Red Domain-4

  15. Group Management Approaches • Subscription model • Sending MN implements multicast • MGMs provide list of subscribers in group • MGMs notify sender of changes • join, leave, move (change IP) • Good for lightweight servers, small groups • Multicast overlay model • MGMs implement multicast + QoS + reliability using transport-level overlay • Scalable in group size, good for low battery clients

  16. Group Management inSubscription Model

  17. MaGMA Group View GROUP X

  18. MaGMA Group View GROUP X

  19. MaGMA Solutions • MGMFlood: Flood all events (join, move,…) to all MGMs • Sends unnecessary control messages to MGMs not in group • MGMLeader: forward group events only to MGMs participating in the group • Less control overhead

  20. view join/move/leave join MaGMA Solution 2:MGMLeader group X Coordinator Needs the group’s view

  21. Inconsistent View Consistency with Concurrent Joins CoordinatorMGM2 LEC1=1 MGM1 MGM3 Ignore MN1join join(MN1) [2,1,1] MN2 join join(MN2) LEC1=2 join(MN1) view join(MN2) [1,1,2] {MGM2, MGM3} view {MGM2, MGM3, MGM1} localview Solution uses a Local Event Counter (LEC) per MGM

  22. HandlingMove • Goal 1: smooth handoff • Goal 2: reduce control overhead • while keeping view consistency group X Coordinator view move move from MGM1 transport tunnel

  23. Coordinator Election • Need to ensure a single coordinator • Need to address coordinator leave • See MWCN paper…

  24. Some Simulation & Analysis Results

  25. Ns2 Simulations & Analysis: MGMFlood vs. MGMLeader Control Overhead Evaluation

  26. Simulation: MaGMA vs. MIP Transport Delay MGM1 functions as the HA

  27. MaGMA Multicast Overlay Model • MGMs organized in overlay • Multicast data forwarded over the overlay

  28. Ongoing and Future Direction • Efficient solutions for multicast overlay model • Keeping MGM-level views not MN-level views • Optimizing overlay, adding QoS support • Mapping groups to optimal servers • Fault-tolerance: tolerating MGM failures and dynamic changes • Advanced application support

  29. Conclusions • Wireless networks (Wi-Fi, WiMAX) will merge with the Internet and cellular infrastructure • Converged B3G will be IP-based • Users will demand support for real-time (RT) groupware such as PTT • Current mobility solutions - inadequate for RT • MaGMA can provide comprehensive support for mobility, group management, and QoS

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