Lectures Top-Down Network Design - Chapter 1: Analyzing Business Goals and Constraints

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1. Top-Down Network Design, Ch. 1: Analyzing Business Goals and Constraints Top-Down Network Design Chapter One Analyzing Business Goals and Constraints Copyright 2010 Cisco Press & Priscilla Oppenheimer Top-Down Network Design • Network design should be a complete process that mat ch es b us iness nee ds to available technology to deliver a system that will maximize an organization’s success. – In the LAN area it is more than just buying a few devices . – In the WAN area it is more than just calling the phone company. Copyright 2004 Cisco Press & Priscilla Oppenheimer Page 1
2. Top-Down Network Design, Ch. 1: Analyzing Business Goals and Constraints Start at the Top • Don’t just start connecting the dots. • Analyze business and technical goals first. • Explore divisional and group structures to find out who the network serves and where they reside. • Determine what applications will run on the network and how those applications bhbehave on a ne twor k. • Focus on Layer 7 and above first. Layers of the OSI Model Layer 7 Application Layer 6 Presentation Layer 5 Session Layer 4 Transport Layer 3 Network Layer 2 Data Link Layer 1 Physical Copyright 2004 Cisco Press & Priscilla Oppenheimer Page 2
3. Top-Down Network Design, Ch. 1: Analyzing Business Goals and Constraints Structured Design • A focus is placed on understanding data flow, data types, and ppgrocesses that access or change the data. • A focus is placed on understanding the location and needs of user communities that access or change data and processes. • Several techniques and models can be used to characterize the existing system, new user requirements, and a structure for the future system. • AlA log ica l mo dliddel is deve lope dbfd before the p hys ica l mo dldel. – The logical model represents the basic building blocks, divided by function, and the structure of the system. – The physical model represents devices and specific technologies and implementations. Systems Development Life Cycles • SDLC: Does it mean Synchronous Data Link Control or Systems Development Life Cycle? • The latter for the purposes of this class! • Typical systems are developed and continue to exist over a period of time, often ca lle d a sys tems deve lopmen t life cycle (SDLC). Copyright 2004 Cisco Press & Priscilla Oppenheimer Page 3
4. Top-Down Network Design, Ch. 1: Analyzing Business Goals and Constraints Top-Down Network Design Steps Analyze requirements Monitor and Develop optimize logical network design performance Implement Develop and test physical network design Test, optimize, and document design Network Design Steps • Phase 1 – Analyze Requirements – Analyze business goals and constraints – Analyze technical goals and tradeoffs – Characterize the existing network – Characterize network traffic Copyright 2004 Cisco Press & Priscilla Oppenheimer Page 4
5. Top-Down Network Design, Ch. 1: Analyzing Business Goals and Constraints Network Design Steps • Phase 2 – Logical Network Design – Design a network topology – Design models for addressing and naming – Select switching and routing protocols – Develop network security strategies – Develop network management strategies Network Design Steps • Phase 3 – Physical Network Design – Select technologies and devices for campus networks – Select technologies and devices for enterprise networks Copyright 2004 Cisco Press & Priscilla Oppenheimer Page 5
6. Top-Down Network Design, Ch. 1: Analyzing Business Goals and Constraints Network Design Steps • Phase 4 – Testing, Optimizing, and DtithNtkDiDocumenting the Network Design – Test the network design – Optimize the network design – Document the network design The PDIOO Network Life Cycle Plan Design Retire Optimize Implement Operate Copyright 2004 Cisco Press & Priscilla Oppenheimer Page 6
7. Top-Down Network Design, Ch. 1: Analyzing Business Goals and Constraints Business Goals • Increase revenue • Reduce operating costs • Improve communications • Shorten product development cycle • Expand into worldwide markets • Build partnerships with other companies • Offer better customer support or new customer services Recent Business Priorities • Mobility • Security • Resiliency (fault tolerance) • Business continuity after a disaster • Network projects must be prioritized based on fiscal goals • Networks must offer the low delay required for real-time applications such as VoIP Copyright 2004 Cisco Press & Priscilla Oppenheimer Page 7
8. Top-Down Network Design, Ch. 1: Analyzing Business Goals and Constraints Business Constraints • Budget •Staffing • Schedule • Politics and policies Collect Information Before the First Meeting • Before meeting with the client, whether internal or external, collect some basic business-related information • Such as – Products produced/Services supplied – Financial viability – Customers, suppliers, competitors – Competitive advantage Copyright 2004 Cisco Press & Priscilla Oppenheimer Page 8
9. Top-Down Network Design, Ch. 1: Analyzing Business Goals and Constraints Meet With the Customer • Try to get – A concise statement of the goals of the project • What problem are they trying to solve? • How will new technology help them be more successful in their business? • What must happen for the project to succeed? Meet With the Customer • What will happen if the project is a failure? – Is this a critical business function? – Is this project visible to upper management? – Who’s on your side? Copyright 2004 Cisco Press & Priscilla Oppenheimer Page 9
10. Top-Down Network Design, Ch. 1: Analyzing Business Goals and Constraints Meet With the Customer • Discover any biases – For example • Will they only use certain company’s products? • Do they avoid certain technologies? • Do the data people look down on the voice people or vice versa? – Talk to the technical and management staff Meet With the Customer – Get a copy of the organization chart • This will show the general structure of the organization • It will suggest users to account for • It will suggest geographical locations to account for Copyright 2004 Cisco Press & Priscilla Oppenheimer Page 10
11. Top-Down Network Design, Ch. 1: Analyzing Business Goals and Constraints Meet With the Customer – Get a copy of the security policy • How does the policy affect the new design? • How does the new design affect the policy? • Is the policy so strict that you (the network designer) won’t be able to do your job? – Start cataloging network assets that security should protect • Hardware, software, applications, and data • Less obvious, but still important, intellectual property, trade secrets, and a company's reputation The Scope of the Design Project • Small in scope? – Allow sal es peopl e t o access net work vi a a VPN • Large in scope? – An entire redesign of an enterprise network • Use the OSI model to clarify the scope – New financial reporting application versus new routinggp protocol versus new data link (wireless, for example) • Does the scope fit the budget, capabilities of staff and consultants, schedule? Copyright 2004 Cisco Press & Priscilla Oppenheimer Page 11
12. Top-Down Network Design, Ch. 1: Analyzing Business Goals and Constraints Gather More Detailed Information • Applications – Now an d a fter th e proj ec t i s comp le te d – Include both productivity applications and system management applications • User communities • Data stores •Protocols • Current logical and physical architecture • Current performance Network Applications Name of Type of New Criticality Comments Application Application Application? Copyright 2004 Cisco Press & Priscilla Oppenheimer Page 12
13. Top-Down Network Design, Ch. 1: Analyzing Business Goals and Constraints Summary • Systematic approach • Focus first on business requirements and constraints, and applications • Gain an understanding of the customer’s corporate structure • Gain an understanding of the customer’s business style Review Questions • What are the main phases of network design per the top-down network design approach? • What are the main phases of network design per the PDIOO approach? • Why is it important to understand your customer’s business style? • What are some typical business goals for organizations today? Copyright 2004 Cisco Press & Priscilla Oppenheimer Page 13