LAN/WAN Optimization Techniques

1. LAN/WAN Optimization Techniques

2. Agenda • Current Traffic • Equipment Inventory and Forecasted Growth • Operational Evaluation Criteria • Network Design Decision Approach

3. Current Traffic • Loads • Traffic classes • Traffic response times • Transaction types • Protocol overhead

4. Loads • Traffic Loads : the volume of data communication traffic -data -data transmission overhead

5. Loads (cont.) • Traffic Load is generally calculated by analytically-based NDTs on the following parameters: -message definition -message characteristics - traffic load is required by NDTs for each location on the network

6. Loads (cont.) • NDTs calculate traffic load based on standard deviations from average values account for these peaks and valleys in traffic volume -peak -normal -valley

7. Traffic classes • Traffic loads should be broken down into these types of traffic classes for message prioritizing -real time -interactive -file transfer

8. Traffic response times • Average transaction response times RT=I+CPU+O

9. Traffic response times (cont.) • Polling environments : I or O =T+W+S

10. Traffic response times (cont.) • Service times • Transmission time is the time needed to send the entire message (overhead and text) down the line

11. Traffic response times (cont.) • Connection delay is the time needed by the front-end processor to establish a connection with terminal, including modem turnarounds • Polling delay is attributed to multipoint lines in which terminals must wait their turn before being polled by the front-end processor

12. Traffic response times (cont.) • Arrival rates: number of messages that arrive at all the terminals on the line • Line utilization (U) • Waiting time (W) P-K formula:

13. Transaction types • The most appropriate approach calculates response time based on the varied mixture of transaction types that each location supports

14. Protocol overhead • Control messages are necessary in both poll and select scenarios to inquire if the terminal has data to send or is ready to receive -polling mode -select mode -control message : requires data rates, line sizes -protocol overhead

15. Protocol overhead (cont.)

16. agenda • Current Traffic • Equipment Inventory and Forecasted Growth • Operational Evaluation Criteria • Network Design Decision Approach

17. Equipment Inventory and Forecasted Growth • Equipment inventory • Inventory • forecasting

18. Equipment inventory • Without an accurate awareness of the communications network, design and analysis is impractical • Equipment inventories and growth forecasts develop an understanding of the network that is fundamental to any engineering process

19. Inventory • An essential of network design is identifying communications equipment • Physical resources -compatibility -meet the needs of the network’s users

20. Inventory (cont.) • Location-in order to identifying communication equipment types, locations of all devices must be specified -equipment types and locations are known, fixed, unalterable -equipment types and location possibilities are known - equipment locations determination accommodates an unlimited selection of possibilities • Types-reference 6.4 communication hardware

21. forecasting • Network engineers need to consider forecasted growth when conducting design exercises • Forecasting growth is critical during network design • Once current and future applications of data communications have been identified, engineer must forecast growth trends in usage over the planning period

22. Forecasting (cont.) • Forecasting based on trends is the safest method of determining the future of data communications traffic demands -trend lines are independent of business activity -outside affects are suspected -trend lines generally follow business activity

23. Forecasting (cont.) • trend lines are not directly dependent on business activity, survey must be conducted in an attempt to explain the independence • Purpose of surveys is to establish the aspects of business activity on which the data communications usage will depend

24. agenda • Current Traffic • Equipment Inventory and Forecasted Growth • Operational Evaluation Criteria • Network Design Decision Approach

25. Operational Evaluation Criteria • Performance • Availability • Reliability • Cost • security

26. Performance • Evaluate what performance criteria are necessary for acceptable operational characteristics of the network -response time -throughput -utilization -blocking rate

27. Availability • Availability -reliability (MTBF) -serviceability (MTTR) • Serial-overall system availability

28. Availability (cont.) • Parallel-overall system availability

29. Reliability • Mean time between failures

30. Cost • Line cost –recurring monthly service charges & nonrecurring one-time installation costs • Equipment cost • Software cost

31. security • The most effective security measures involve a variety of barriers of different types and different places

32. agenda • Current Traffic • Equipment Inventory and Forecasted Growth • Operational Evaluation Criteria • Network Design Decision Approach

33. Network Design Decision Approach • Network design tool utilization • Cost-performance break-even analysis • Equipment acquisition

34. Network design tool utilization • This step involved selection of the most appropriate design technique, acquisition of an NDT, development of a network model, and analysis of the model --most critical step of the entire network engineering process

35. Network design phase

36. Cost-performance break-even analysis • This step involved generating and evaluating alternative network designs • What-if questions are used to evaluate various alternative configurations -proposals for adding / deleting resources -redesign application to improve the performance -modeling different routing strategies

37. Cost-performance break-even analysis (cont.) • Each of the various alternative configurations will have associated costs and performance levels • Trade-off between cost/performance

38. Equipment acquisition • This step involves obtaining the necessary equipment as specified in the optimal optimized network design • Once this step is complete, an optimized implementable design is available as input into the next phase: network management