1. Chapter 14 Network Design and Implementation

2. 2 Network Analysis and Design Aspects of network analysis and design Understanding the requirements for a communications network Need to decide how detailed the analysis must be Example: just install more capacity than needed to avoid time consuming estimates of required capacity Investigating alternative ways for implementing the network Selecting the most appropriate alternative to provide the required capability Similar considerations used for voice and data networks Usually involves a multi-step process

3. 3 Network Implementation Process of installing a network and making it operational

4. 4 Project Approach Network analysis, design and implementation usually done in multi-phase project Main objective: Provide network satisfying user requirements at an appropriate cost May outsource the project Usually the case for small businesses

5. 5 Network Project Steps 1.The request 2.Preliminary investigation and feasibility study 3. Detailed understanding and definition of requirements 4.Investigation of alternatives 5. Network design 6.Selection of vendors and equipment 7.Calculation of costs 8.Documentation of network design and implementation plan

6. 6 Network Project Steps 9.Approval by management 10. Equipment order 11. Preparation for implementation 12. Installation 13. Training 14. System testing 15. Cutover 16. Implementation cleanup and audit

7. 7 Preliminary Investigation A small preliminary project team is formed to examine existing communication system Determine what improvements are necessary Estimate costs and schedule Creeping commitment of resources Ramp up project personnel and expenditures as needed Helps minimize financial risk if project is stopped

8. 8 Project Life Cycle

9. 9 Definition of Requirements Breakdown requirements by Geography Traffic loads (peak and average) Transaction-based network loads are easier to estimate Internet-type environments are more difficult to estimate due to different traffic types (images, sound, video) Flow pattern i.e. Star vs. mesh  Traffic in star flows through central node  Traffic in mesh has more complex pattern Response time and reliability

10. 10 Definition of Requirements Future growth Completion date Compatibility with old network Costs

11. 11 Typical Data Network Traffic Load

12. 12 Analysis of Expected Traffic Loads

13. 13 Investigate Alternatives Check availability of different services Public switched vs. private lines Topology type Is packet switching available? Satellite?

14. 14 Network Design Iterative process Refinements made as project progresses Translate specs to drawings Simulate the design Allows “what if” scenarios Simulation model can be difficult to create Calculate response times Example: Require transmission of 100 million characters in an 8-hour day with no longer than 1 second response time

15. 15 Network Diagram

16. 16 Response Time Design Example

17. 17 Equipment and Vendor Selection Evaluate types of equipment available Send out Request Request for Quotation (RFQ) to vendors of “commodity” products and services. Request for Proposal (RFP) to vendors of “custom” products and services. Detail required by vendor in response to RFQ/RFP varies based on application Evaluate vendor proposals

18. 18 Example RFP

19. 19 Example Vendor Response to RFP

20. 20 Calculate Costs Examine costs of alternate designs Group costs by Circuit costs Modem costs Other hardware costs Software costs Personnel costs

21. 21 Documentation of Design Include: Specifications Software and versions Wiring diagrams Equipment list

22. 22 Management Approval of Design Present design and cost/benefit information to management Design review

23. 23 Network Implementation Equipment Order Make sure equipment specs meet your needs Make purchase contingent on acceptance test (expensive items) Watch out for lead times Prepare for Implementation Set up network policies Modify software Track progress

24. 24 Network Implementation Installation Allocate and prepare space Mechanical drawings showing locations Have vendors install and test equipment Make sure equipment interfaces properly Training Train users, operational and maintenance personnel

25. 25 Network Implementation System Testing Perform as much testing as possible initially Locate and solve problems May need to test hardware and software separately Schedule tests when network has minimum load Stress test to find network limits Workload generator – software that produces network traffic Test component error handling capability Failure to test error recovery is a major oversight Can the network recover?

26. 26 Network Implementation Cutover High visibility event Typically scheduled for weekend Problems can occur Good idea to have technicians from equipment vendor companies on hand during cutover Implementation Cleanup and Audit Make adjustments Revise documentation Audit Find out if benefits of new network are as expected Interview users and support personnel