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A simulation study of GELS (GMPLS-controlled Ethernet Label Switching) for Ethernet over WAN

A simulation study of GELS (GMPLS-controlled Ethernet Label Switching) for Ethernet over WAN. Muhammad Saqib Ilyas ( msaqib@ieee.org ) School of Science and Engineering LUMS, Lahore, Pakistan. Co-authors: Atif Nazir, Fawaz Saleem Bokhari, Zartash Afzal Uzmi (LUMS)

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A simulation study of GELS (GMPLS-controlled Ethernet Label Switching) for Ethernet over WAN

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  1. A simulation study of GELS (GMPLS-controlled Ethernet Label Switching) for Ethernet over WAN Muhammad SaqibIlyas (msaqib@ieee.org) School of Science and Engineering LUMS, Lahore, Pakistan Co-authors: Atif Nazir, Fawaz Saleem Bokhari, Zartash Afzal Uzmi (LUMS) Fahad Dogar (CMU, Pittsburgh) Adrian Farrel (Old Dog Consulting) Work sponsored by: Siemens Corporate Technology Division Munich, Germany IEEE Globecom 2007 Washington, D.C. Wednesday, Nov 28, 2007

  2. Agenda • GMPLS – Background • Ethernet – Background • GELS Architecture • GMPLS as the control plane for Ethernet • Simulation Modeling and Setup • Simulation Results • Summary and Conclusions

  3. IP Routing Dest: 150.10.10.1 Longest prefix match

  4. Forwarding in MPLS Label: 13 Label: 10 Label lookup

  5. MPLS challenges • Newer devices are capable of switching on the basis of: • Interface (FSC) • Wavelength (LSC) • TDM timeslot • MPLS works with packet switch devices only • Looks at the label and forwards an incoming packet • Solution: • Generalize MPLS to GMPLS (RFC 3945) Incompatibility of MPLS with newer devices GMPLS offers a control plane for devices with ANY data plane

  6. Ethernet • Dominant LAN transport technology • Speed and reach grew substantially in the last 25 years • Very flexible and cost-effective transport • Ethernet is seeing increasing deployment in service provider networks

  7. Ethernet in the core - challenges • Existing control plane (STP) • Network link utilization – Low • Resilience mechanism – Slow • Rudimentary support for QoS and TE Spanning tree computed Spanning tree recomputed Link failure

  8. GELS • Proposes to use GMPLS control plane for the Ethernet data plane! Ethernet Bridge • GELS is in draft stages in IETF • No quantitative performance comparison available so far Ethernet control plane GMPLS control plane Ethernet data plane

  9. Our work • Simulation based evaluation of GELS • Rapid STP (RSTP) versus GMPLS • How does old control plane compare with new control plane? • Considered: • Normal network operation • Single element failures

  10. Evaluation Criteria How efficiently can we use the network? GELS Recovery Schemes How quickly can we recover from failure?

  11. Evaluation challenges • How to compare contention-based Ethernet with reservation based GMPLS? • Allow partial placement of LSPs in GMPLS instead of YES/NO placement LSP not placed Bandwidth placed: 0% LSP placed Bandwidth placed: 60% Available: 15 Available: 0 GMPLS with Compromised CSPF GMPLS with CSPF Capacity: 100 Request: 25 Placed: 0 Placed: 15

  12. GELS: Convergence time Restoration: trest = tsig+ tproc+ tres+ tsw Reserve new LSP tres: Reservation delay Switch traffic onto new LSP tsw: Switching delay Protection: tprot = tsig + tsw Compute new LSP tproc: Processing delay Potential new path Link failure LSP Ingress Egress Failure notification sent to ingress tsig: Signaling delay Nearest upstream node to the failure

  13. Timing parameter values • tsig(Signaling delay): • Based on 1ms/200 km link propagation delay • tproc(Processing delay): • 5ms • tres(Reservation delay): • Based on 1ms/200 km link propagation delay • tsw(Switching delay): • 1ms

  14. GELS restoration recovery time LSP 1 LSP 2 Ingress has lost multiple LSPs Nearest upstream node for LSP 1 Sequentially Convergence time is tmax • Compute • Reserve • Switch Sequentially Or In parallel Convergence time is tmin Link failure Nearest upstream node for LSP 2 Sequentially Failure signaled to ingress

  15. Helsinki (1) Oslo (2) Stockholm (3) Glasgow (4) Copenhagen (1) Belfast (5) Copenhagen (6) Liverpool (8) Dublin (7) Birmingham (9) London (2) Amsterdam (3) Berlin (4) Hamburg (12) Amsterdam (11) Berlin (13) Warsaw (14) London (10) Brussels (15) Dusseldorf (16) Leipzig (18) Brussels (5) Luxembourg (6) Prague (7) Krakow (23) Frankfurt (17) Prague (22) Strasbourg (20) Munich (21) Paris (19) Budapest (28) Paris (8) Zurich (9) Vienna (10) Basel (25) Zurich (26) Vienna (24) Salzburg (27) Graz (29) Bordeaux (30) Lyon (31) Milan (32) Zagreb (33) Milan (11) Toulouse (34) Belgrade (37) Bukarest (38) Porto (39) Turin (35) Marseille (42) Bologna (36) Zaragoza (40) Sofia (46) Barcelona (41) Rome (45) Madrid (44) Lisbon (43) Neapel (48) Seville (47) Athens (50) Palermo (49) Simulation setup - networks COST 266: 50 nodes COST 239: 11 nodes

  16. Traffic matrices • LSP requests arrive one-by-one • Randomly chosen ingress and egress nodes • Bandwidth request 1, 2 or 3 Gb/s chosen with equal probability

  17. Simulation environment • Based on: • Bridgesim1 for native Ethernet • TOTEM2 for GMPLS-controlled Ethernet • Enhancements to simulators: • Implementation of C-CSPF • Computation of recovery time 1: http://www.cs.cmu.edu/~acm/bridgesim/index.html 2: http://totem.info.ucl.ac.be/

  18. Results: LSP placement percentage GELS with protection places fewer LSPs than RSTP GELS with restoration places more LSPs than RSTP

  19. Results: Bandwidth placement GELS with restoration places more bandwidth than RSTP GELS with protection places less (primary) bandwidth than RSTP

  20. Results: Average link utilization GELS with protection quickly approaches almost full link utilization GELS approaches 92% average link utilization RSTP has lowest average link utilization

  21. Results: RSTP convergence time vs cost to root RSTP convergence time is highest if the root bridge fails Convergence time decreases as cost to root increases

  22. Results: Single link failure convergence time More links closer to root bridge in COST 266 More LSPs were restored in COST 239

  23. Results: Node failure convergence time Small value t1 - t10 are in milliseconds 50+ 11 Small value 50+ t1 – t49 are in milliseconds 50

  24. Summary • About 45% improvement with GELS over native Ethernet in: • LSP acceptance • Bandwidth placement • Failure recovery time orders of magnitude less for GELS than for native Ethernet

  25. Conclusion • Ethernet is a flexible, cost effective and efficient transport mechanism for metro/core networks • GMPLS promises to be a useful control plane for Ethernet in metro/core • Tremendous administrative benefits of using a single control plane • Vendors actively working on standardization of GELS

  26. Questions? • Contact: msaqib@gmail.com • Simulator: http://suraj.lums.edu.pk/gels/

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