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Graded Channel Reservation with Path Switching in Ultra High Capacity Networks

Graded Channel Reservation with Path Switching in Ultra High Capacity Networks. Reuven Cohen, Niloofar Fazlollahi , David Starobinski ECE Dept., Boston University Gridnets Workshop 2006 San Jose, CA. Acknowledgements. US Department of Energy Dr. N. Rao, ORNL. Outlines.

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Graded Channel Reservation with Path Switching in Ultra High Capacity Networks

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  1. Graded Channel Reservation with Path Switching in Ultra High Capacity Networks Reuven Cohen, Niloofar Fazlollahi, David Starobinski ECE Dept., Boston University Gridnets Workshop 2006 San Jose, CA

  2. Acknowledgements • US Department of Energy • Dr. N. Rao, ORNL

  3. Outlines • Advanced Channel Reservation • Contributions • Models and Algorithms • Related work • Variants • Performance Evaluation • Conclusion

  4. Motivation • Grid computation : Large Hadron Collider (LHC) at CERN • Exabytes (1018 bytes) → need for new protocol to support huge file transfers http://lhc.web.cern.ch/lhc/LHC_Experiments.htm

  5. Advanced Channel Reservation • Emergence of new protocol stack • complements TCP/IP • Properties: 1 - Users request resources for connection in advance (bandwidth/duration, file size) 2 – Dedicated resources allocated by a scheduler (centralized or replicated) 3 – Implemented directly on top of layer 2

  6. UltraScience Net http://www.csm.ornl.gov/ultranet/

  7. ACR Challenges • Scheduling • Routing • Goal: maximum utilization of resources Earliest Shortest A B

  8. Graded Channel Reservation (GCR) Contributions: • path grading multi-criteria path optimization (shortest, earliest) • path switching connection can switch between paths • Complexity analysis (small polynomial) • Performance evaluation

  9. Model Model: • G (V,E) V: {A, B, C} E: {AB, AC, BC} • requests: • response: (time,path) Objective: Highest grade path B Source Destination Bandwidth Duration A C

  10. Grading Example • Primary grading criterion: earliest path • Secondary grading criterion: • Shortest • Widest

  11. Example (Cont.) • Thm: • GCR always returns the earliest time at which a path satisfying requested bandwidth B and duration T can be established between nodes s and d. • Return path with highest grade (e.g., earliest-shortest)

  12. GCR Algorithm: • Time slots: connection set up/ tear down • Steady state residual graph • Graph intersection • yes - highest grade path no – start from next slot • Reserve bandwidths BFS path search

  13. Related Work • Most closely related: Guerin & Orda, INFOCOM, 2000 Rao, Wing, Carter & Wu, IEEE ComSoc Mag., 2005 • Focus on single criterion optimization • No path switching • Limited performance evaluation

  14. Advantage of path switching Request: (A,C) at time 2:00 pm, duration = 4 hours A A A B B B C C C Slot 1: [1,1:30] Slot 2: [1:30,2] Slot 2: [1:30,4] Slot 3: [2,4] A A B B No switch Switch C C Slot 3: [4,8] Slot 4: [4,6] Slot 5: [6,8]

  15. Variants to GCR • GCRswitch • Switch to best grade path available at each slot

  16. Reducing Path Switches • GCRminimum • Thm: GCRminimum returns the earliest path and minimizes number of path switches. • GCRlimitx • Heuristic: limits up to x switches

  17. Performance measures: 1- average delay 2- saturation throughput Requests: (s,d,B,T) Parameters: uniform source uniform or hot-spot destination uniform or 80/20 bandwidth exponential or heavy-tailed connection length Simulation measures & parameters

  18. Topologies

  19. Performance Evaluations

  20. Performance Evaluations

  21. Conclusion • Framework: grading & switching • 1st and 2nd path optimization important • Path switching widely improves performance

  22. Future Work • Time window: simulating blocking probability • Cost of switching

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