1. LAN/WAN Optimization Techniques

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

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

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

5. Loads (cont.) Traffic Load is generally calculated by analytically-based NDTs on the following parameters: Traffic Load is generally calculated by analytically-based NDTs on the following parameters: -message definition -message definition -message characteristics -message characteristics - traffic load is required by NDTs for each location on the network - 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 NDTs calculate traffic load based on standard deviations from average values account for these peaks and valleys in traffic volume -peak -peak -normal -normal -valley -valley

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

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

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

10. Traffic response times (cont.) Service times Service times Transmission time is the time needed to send the entire message (overhead and text) down the line 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 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 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 Arrival rates: number of messages that arrive at all the terminals on the line Line utilization (U) Line utilization (U) Waiting time (W) Waiting time (W) P-K formula: 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 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 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 -polling mode -select mode -select mode -control message : requires data rates, line sizes -control message : requires data rates, line sizes -protocol overhead -protocol overhead

15. Protocol overhead (cont.)

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

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

18. Equipment inventory Without an accurate awareness of the communications network, design and analysis is impractical 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 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 An essential of network design is identifying communications equipment Physical resources Physical resources -compatibility -compatibility -meet the needs of the network’s users -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 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 locations are known, fixed, unalterable -equipment types and location possibilities are known -equipment types and location possibilities are known - equipment locations determination accommodates an unlimited selection of possibilities - equipment locations determination accommodates an unlimited selection of possibilities Types-reference 6.4 communication hardware Types-reference 6.4 communication hardware

21. forecasting Network engineers need to consider forecasted growth when conducting design exercises Network engineers need to consider forecasted growth when conducting design exercises Forecasting growth is critical during network design 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 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 Forecasting based on trends is the safest method of determining the future of data communications traffic demands -trend lines are independent of business activity -trend lines are independent of business activity -outside affects are suspected -outside affects are suspected -trend lines generally follow business activity -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 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 Purpose of surveys is to establish the aspects of business activity on which the data communications usage will depend

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

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

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

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

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

29. Reliability Mean time between failures Mean time between failures

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

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

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

33. Network Design Decision Approach Network design tool utilization Network design tool utilization Cost-performance break-even analysis Cost-performance break-even analysis Equipment acquisition 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 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 --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 This step involved generating and evaluating alternative network designs What-if questions are used to evaluate various alternative configurations What-if questions are used to evaluate various alternative configurations -proposals for adding / deleting resources -proposals for adding / deleting resources -redesign application to improve the performance -redesign application to improve the performance -modeling different routing strategies -modeling different routing strategies

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

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