1. ECEN4533 Data Communications Lecture #2125 February 2013 Dr. George Scheets n Read 11.4 n Problems: Chapter 11.2, 4, & 5 n Quiz #2, 25 March (Live) < 1 April (DL)

2. ECEN4533 Data Communications Lecture #2227 February 2013 Dr. George Scheets n Read 11.5 n Corrected Exams u Due 6 March (Live) u One week after return (DL) n Scan Design Problem #2

3. ECEN4533 Data Communications Lecture #231 March 2013 Dr. George Scheets n Read 11.6.1, 11.7 n Problems Web 13-15 n Corrected Exams u Due 6 March (Live) u One week after return (DL) n Design #2 u Due 15 March (Live) u Due 22 March (DL)

4. RedNeckNet Low Bid n Cost = $12, 643.40 per month n Promoted to MegaMoron Senior Engineer u Tsega Debele

5. Design #2 Improved RedNeckNet n Combined Traffic Options (Pick One): u (1) Standard Internet (FIFO) u (2) QoS Enabled Internet u (3) ATM: VBR Video, UBR Data n Redundancy: Two Connectivity n Analysis u Calculate Single Hop Delays F Queuing + Propagation Delays u Multiple Hop Delays = sum of single Hops u Make sure you account for the overhead!!! F Traffic Matrix is application traffic

6. Design Comments: n Link Costs u Proportional to distance 1.0 traffic 0.0 ? Centralized Star is best. u Proportional to distance 0.0 traffic 1.0 ? Full Mesh is Best. F Ours is proportional to distance 0.22 traffic 0.77 u Otherwise pay attention to traffic matrix High traffic node? Generally best to have many links.

7. Classical Queuing Theory n M/x/x u Exponentially Distributed IAT n M/G/1, M/M/1, M/D/1 u Single server, various packet distributions n M/M/1 with priorities n M/M/a u Several (a) output servers

8. Real vs Artificial Trace 10 Seconds Real Traffic 10 Seconds Artificial M/M/1 Traffic Source: Willinger et al, "Self-Similarity through High Variability", IEEE/ACM Transactions on Networking, February 1997.

9. Real vs Artificial Trace 100 Seconds Real Traffic 100 Seconds Artificial M/M/1 Traffic

10. Real vs Artificial Trace 16.7 Minutes Real Traffic 16.7 Minutes Artificial M/M/1 Traffic

11. Real vs Artificial Trace 167 Minutes Real Traffic 167 Minutes Artificial M/M/1 Traffic

12. Real vs Artificial Trace 27.78 Hours Real Traffic 27.78 Hours Artificial M/M/1 Traffic

13. Self Similar Behavior

14. Fall 2002 Final n 'Average' based on 1 test chosen at random 126.00 out of 150 u One point average X 1 n 'Average' based on 10 tests chosen randomly 109.44 out of 150 u Ten point average X 10 n Actual Midterm Average 106.85 out of 150

15. Harold Edwin Hurst (1880-1978) British Hydrologist Found Long Term Dependence in Reservoir Storage.

16. One way to estimate H nCnCnCnCompute Variance of original trace, X nMnMnMnMerge 10 consecutive points into new point Y Y = 10 point average of X Compute variance of this new trace nMnMnMnMerge 10 consecutive points of Y into new point Z Z = 100 point average of X Compute variance of this new trace nHnHnHnHow is variance decreasing? uBuBuBuBy factor of N? Not self-similar, H = 0.5 uBuBuBuBy factor of N2(1-H)? Evidence of self-similarity

17. Classical Queuing Theory Vs. Self Similar 0% 100% Offered Load M/D/1M/M/1 Average Delay Self Similar

18. Traffic Rate over time Source: "Dimensioning Network Links", IEEE Network Magazine, April 2009

19. Carrying Capacity % of Line Speed carrying Application Traffic Line Speed Load (63% Active)37% Idle 84% Traffic16% Overhead Carrying Capacity = Traffic Moved/Line Speed = 84% * 63% = 53%

20. Carrying Capacity n Estimate Packet/Cell overhead n Estimate Traffic Characteristics u Classical? u Self-Similar? What is Hurst Parameter? n Estimate allowable trunk load u Delay constrained? (low speed tendency) u Buffer constrained? (high speed tendency) n Calculate Carrying Capacity = (% Trunk Load)(% of Traffic in packet/cell)

21. Low Speed Links Likely Delay Constrained Plenty of Memory Available 0% 100% Offered Load Average Delay 50% Target Average Target Maximum PDF

22. High Speed Links Likely Memory Constrained Plenty of Time Available 0% 100% Offered Load 50% Memory Limit Queue Size Target Average

23. Circuit Switch TDM Trunking (Leased Line Telephone Network) TDM Switch SONET OC-N Fixed Rate Traffic Bursty Data Traffic Assumptions: Fixed Rate Traffic gets fixed number of time slots. (N Bytes every 1/8000th second). Bursty Data Traffic channels get fixed number of time slots based on peak (line) input rates.

24. Carrier Leased Line Network Leased Line ‘Cloud’ Trunk capacity shared via TDM & Circuit Switching Cross-Connect Trunks Leased Line

25. Packet Switch StatMux Trunking (Pure Internet Model) Router SONET OC-N Fixed Rate Traffic Bursty Data Traffic Assumptions: All traffic is packetized & Statistically Multiplexed onto the trunk BW.

26. Internet Service Provider Backbone Router Trunks Leased Line ISP ‘Cloud’ Trunk capacity shared via StatMux & Packet Switching

27. Cell Switch StatMux Trunking (ATM Model) ATM Switch SONET OC-N Fixed Rate Traffic Bursty Data Traffic Assumptions: Fixed rate traffic moved over CBR VC's. Gets reserved bandwidth and near-TDM like service. Data or Variable Rate Traffic is StatMuxed onto the trunk bandwidth that’s not reserved for CBR.

28. ATM Backbone ATM ‘Cloud’ Trunks use StatMux/TDM & Cell Switching ATM Switch Trunks Leased Line

29. Switched Network Carrying Capacities High Speed Trunk (OC-3) 0% Bursty 100% Bursty 100% Fixed Rate 0% Fixed Rate Offered Mix Carrying Capacity Circuit Switch TDM Packet Switch StatMux Cell Switch StatMux

30. Traffic Growth Voice Data time

31. 70’s & 80’s Voice Dominates Voice Data time 70’s & 80’s

32. Switched Network Carrying Capacities High Speed Trunks Carrying Capacity Circuit Switch TDM 0% Bursty 100% Bursty 100% Fixed Rate 0% Fixed Rate Offered Traffic Mix

33. Turn of the Century A Mixed Traffic Environment Voice Data time 2000

34. Switched Network Carrying Capacities High Speed Trunks Carrying Capacity Cell Switch StatMux 0% Bursty 100% Bursty 100% Fixed Rate 0% Fixed Rate Offered Traffic Mix

35. Today, Data Dominates Voice Data time 2013

36. Switched Network Carrying Capacities High Speed Trunks Carrying Capacity Packet Switch StatMux 0% Bursty 100% Bursty 100% Fixed Rate 0% Fixed Rate Offered Traffic Mix

37. The Big Unknown... What impact will Video have? n If Video becomes dominant, is a packet switched statmux network best?

38. ISO OSI Seven Layer Model n Layer 7 Application Word Perfect n Layer 6 Presentation Windows API n Layer 5 Session TCP, Windows n Layer 4 TransportTCP, Windows n Layer 3 Network IP, Windows n Layer 2 Data LinkPC NIC n Layer 1 Physical PC NIC