Top-Down Network Design

A systems analysis approach to enterprise network design Master techniques for checking the health of an existing network to develop a baseline for measuring performance of a new network design Explore solutions for meeting QoS requirements, including ATM traffic management, IETF controlled-load and guaranteed services, IP multicast, and advanced switching, queuing, and routing algorithms Develop network designs that provide the high bandwidth and low delay required for real-time applications such as multimedia, distance learning, and videoconferencing Identify the advantages and disadvantages of various switching and routing protocols, including transparent bridging, Inter-Switch Link (ISL), IEEE 802.1Q, IGRP, EIGRP, OSPF, and BGP4 Effectively incorporate new technologies into enterprise network designs, including VPNs, wireless networking, and IP Telephony Top-Down Network Design, Second Edition, is a practical and comprehensive guide to designing enterprise networks that are reliable, secure, and manageable. Using illustrations and real-world examples, it teaches a systematic method for network design that can be applied to campus LANs, remote-access networks, WAN links, and large-scale internetworks. You will learn to analyze business and technical requirements, examine traffic flow and QoS requirements, and select protocols and technologies based on performance goals. You will also develop an understanding of network performance factors such as network utilization, throughput, accuracy, efficiency, delay, and jitter. Several charts and job aids will help you apply a top-down approach to network design. This Second Edition has been revised to include new and updated material on wireless networks, virtual private networks (VPNs), network security, network redundancy, modularity in network designs, dynamic addressing for IPv4 and IPv6, new network design and management tools, Ethernet scalability options (including 10-Gbps Ethernet, Metro Ethernet, and Long-Reach Ethernet), and networks that carry voice and data traffic. Top-Down Network Design, Second Edition, has a companion website at http://www.topdownbook.com, which includes updates to the book, links to white papers, and supplemental information about design resources. This book is part of the Networking Technology Series from Cisco Press¿ which offers networking professionals valuable information for constructing efficient networks, understanding new technologies, and building successful careers.

Table of Contents:
I. IDENTIFYING YOUR CUSTOMER'S NEEDS AND GOALS. 1. Analyzing Business Goals and Constraints. Using a Top-Down Network Design Methodology. Using a Structured Network Design Process. Systems Development Life Cycles. The Plan Design Implement Operate Optimize (PDIOO) Network Life Cycle. Analyzing Business Goals. Working with Your Client. Changes in Enterprise Networks. Resiliency. Typical Network Design Business Goals. Identifying the Scope of a Network Design Project. Identifying a Customer's Network Applications. Analyzing Business Constraints. Politics and Policies. Budgetary and Staffing Constraints. Project Scheduling. Business Goals Checklist. Summary. 2. Analyzing Technical Goals and Tradeoffs. Scalability. Planning for Expansion. Expanding Access to Data. Constraints on Scalability. Availability. Specifying Availability Requirements. Network Performance. Network Performance Definitions. Optimum Network Utilization. Throughput. Throughput of Internetworking Devices. Application Layer Throughput. Accuracy. Efficiency. Delay and Delay Variation. Causes of Delay. Delay Variation. Response Time. Security. Identifying Network Assets. Analyzing Security Risks. Reconnaissance Attacks. Denial-of-Service Attacks. Developing Security Requirements. Manageability. Usability. Adaptability. Affordability. Making Network Design Tradeoffs. Technical Goals Checklist. Summary. 3. Characterizing the Existing Internetwork. Characterizing the Network Infrastructure. Developing a Network Map. Characterizing Network Addressing and Naming. Characterizing Wiring and Media. Checking Architectural and Environmental Constraints. Checking the Health of the Existing Internetwork. Analyzing Network Availability. Analyzing Network Utilization. Measuring Bandwidth Utilization by Protocol. Analyzing Network Accuracy. Analyzing Errors on Switched Ethernet Networks. Analyzing Network Efficiency. Analyzing Delay and Response Time. Checking the Status of Major Routers, Switches, and Firewalls. Tools for Characterizing the Existing Internetwork. Network-Monitoring and Management Tools. Remote Monitoring Tools. Cisco Tools for Characterizing an Existing Internetwork. Organizations That Provide Information on Characterizing an Existing. Internetwork. Network Health Checklist. Summary. 4. Characterizing Network Traffic. Characterizing Traffic Flow. Identifying Major Traffic Sources and Stores. Documenting Traffic Flow on the Existing Network. Characterizing Types of Traffic Flow for New Network Applications. Terminal/Host Traffic Flow. Client/Server Traffic Flow. Thin Client Traffic Flow. Peer-to-Peer Traffic Flow. Server/Server Traffic Flow. Distributed Computing Traffic Flow. Traffic Flow in Voice over IP Networks. Documenting Traffic Flow for New and Existing Network Applications. Characterizing Traffic Load. Calculating Theoretical Traffic Load. Documenting Application-Usage Patterns. Refining Estimates of Traffic Load Caused by Applications. Estimating Traffic Overhead for Various Protocols. Estimating Traffic Load Caused by Workstation and Session Initialization. Estimating Traffic Load Caused by Routing Protocols. Characterizing Traffic Behavior. Broadcast/Multicast Behavior. Network Efficiency. Frame Size. Protocol Interaction. Windowing and Flow Control. Error-Recovery Mechanisms. Characterizing Quality of Service Requirements. ATM Quality of Service Specifications. IETF Integrated Services Working Group Quality of Service Specifications. IETF Differentiated Services Working Group Quality of Service Specifications. Grade of Service Requirements for Voice Applications. Documenting QoS Requirements. Network Traffic Checklist. Summary. Summary for Part I. II. LOGICAL NETWORK DESIGN. 5. Designing a Network Topology. Hierarchical Network Design. Why Use a Hierarchical Network Design Model? The Classic Three-Layer Hierarchical Model. Guidelines for Hierarchical Network Design. Redundant Network Design Topologies. Backup Paths. Load Sharing. Modular Network Design. Designing a Campus Network Design Topology. The Spanning Tree Protocol. Scaling the Spanning Tree Protocol. Virtual LANs. Wireless LANs. Redundancy and Load Sharing in Wired LANs. Server Redundancy. Workstation-to-Router Redundancy. Designing the Enterprise Edge Topology. Redundant WAN Segments. Multihoming the Internet Connection. Virtual Private Networking. The Service Provider Edge. Secure Network Design Topologies. Planning for Physical Security. Meeting Security Goals with Firewall Topologies. Summary. 6. Designing Models for Addressing and Naming. Guidelines for Assigning Network Layer Addresses. Administering Addresses by a Central Authority. Distributing Authority for Addressing. Using Dynamic Addressing for End Systems. Using Private Addresses in an IP Environment. ng a Hierarchical Model for Assigning Addresses. Why Use a Hierarchical Model for Addressing and Routing? Hierarchical Routing. Classless Interdomain Routing. Classless Routing Versus Classful Routing. Route Summarization (Aggregation). Discontiguous Subnets. Variable-Length Subnet Masking. Hierarchy in IP Version 6 Addresses. Designing a Model for Naming. Distributing Authority for Naming. Guidelines for Assigning Names. Assigning Names in a NetBIOS Environment. Assigning Names in an IP Environment. Summary. 7. Selecting Switching and Routing Protocols. Making Decisions as Part of the Top-Down Network Design Process. Selecting Bridging and Switching Protocols. Transparent Bridging. Transparent Switching. Selecting Spanning Tree Protocol Enhancements. Protocols for Transporting VLAN Information. Selecting Routing Protocols. Characterizing Routing Protocols. IP Routing. AppleTalk Routing. Novell NetWare Routing. Using Multiple Routing Protocols in an Internetwork. A Summary of IP, AppleTalk, and IPX Routing Protocols. Summary. 8. Developing Network Security Strategies. Network Security Design. Identifying Network Assets and Risks. Analyzing Security Tradeoffs. Developing a Security Plan. Developing a Security Policy. Developing Security Procedures. Security Mechanisms. Physical Security. Authentication. Authorization. Accounting (Auditing). Data Encryption. Packet Filters. Firewalls. Intrusion Detection Systems. Modularizing Security Design. Securing Internet Connections. Securing Remote-Access and Virtual Private Networks. Securing Network Services and Network Management. Securing Server Farms. Securing User Services. Securing Wireless Networks. Summary. 9. Developing Network Management Strategies. Network Management Design. Network Management Processes. Fault Management. Configuration Management. Security Management. Accounting Management. Network Management Architectures. Centralized Versus Distributed Monitoring. Selecting Protocols for Network Management. Simple Network Management Protocol. Cisco Discovery Protocol. Estimating Network Traffic Caused by Network Management. Selecting Tools for Network Management. Cisco Tools. Summary. Summary for Part II. III. PHYSICAL NETWORK DESIGN. 10. Selecting Technologies and Devices for Campus Networks. LAN Cabling Plant Design. Cabling Topologies. Types of Cables. LAN Technologies. Ethernet. Campus ATM Networks. Selecting Internetworking Devices for a Campus Network Design. Optimization Features on Campus Internetworking Devices. An Example of a Campus Network Design. Background Information for the Campus Network Design Project. Business Goals. Technical Goals. Network Applications. User Communities. Data Stores (Servers). The Current Network at WVCC. The Network Redesign for WVCC. Summary. 11. Selecting Technologies and Devices for Enterprise Networks. Remote-Access Technologies. Point-to-Point Protocol. Integrated Services Digital Network. Cable Modem Remote Access. Digital Subscriber Line Remote Access. Selecting Remote-Access Devices for an Enterprise Network Design. Selecting Devices for Remote Users. Selecting Devices for the Central Site. WAN Technologies. Systems for Provisioning WAN Bandwidth. Leased Lines. Synchronous Optical Network. Frame Relay. ATM Wide-Area Networks. Selecting Routers for an Enterprise WAN Design. Selecting a WAN Service Provider. An Example of a WAN Design. Business and Technical Goals. Network Applications. User Communities. Data Stores (Servers). The Current Network. The WAN Design for Klamath Paper Products. Summary. Summary for Part III. IV. TESTING, OPTIMIZING, AND DOCUMENTING YOUR NETWORK DESIGN. 12. Testing Your Network Design. Using Industry Tests. Building and Testing a Prototype Network System. Determining the Scope of a Prototype System. Writing a Test Plan for the Prototype System. Implementing the Test Plan. Tools for Testing a Network Design. Types of Tools. Specific Tools for Testing a Network Design. An Example of a Network Design Testing Scenario. Goals for the Design and Testing Project. Network Applications. The Current Network. Testing Methods Used. Measured Data. Analysis of the New Order-Entry System. Conclusions. Summary. 13. Optimizing Your Network Design. Optimizing Bandwidth Usage with IP Multicast Technologies. IP Multicast Addressing. The Internet Group Management Protocol. Multicast Routing Protocols. Reducing Serialization Delay. Link-Layer Fragmentation and Interleaving. Compressed Real Time Protocol. Optimizing Network Performance to Meet Quality of Service Requirements. IP Precedence and Type of Service. IP Version 6 QoS. The Resource Reservation Protocol. The Common Open Policy Service Protocol. Classifying LAN Traffic. Cisco Internetwork Operating System Features for Optimizing Network Performance. Switching Techniques. Queuing Services. Random Early Detection. Traffic Shaping. Committed Access Rate. Summary. 14. Documenting Your Network Design. Responding to a Customer's Request for Proposal. Contents of a Network Design Document. Executive Summary. Project Goal. Project Scope. Design Requirements. Business Goals. Technical Goals. User Communities and Data Stores. Network Applications. Current State of the Network. Logical Design. Physical Design. Results of Network Design Testing. Implementation Plan. Project Schedule. Project Budget. Return on Investment. Design Document Appendix. Summary. Appendix A: Characterizing Network Traffic When Workstations Boot. Appendix B: References and Recommended Reading. Glossary.

About the Author :
Priscilla Oppenheimer has been developing data communications and networking systems since 1980 when she earned her master's degree in information science from the University of Michigan. After many years as a software developer, she became a technical instructor and training developer and taught more than 2000 network engineers from most of the Fortune 500 companies. Her employment at such companies as Apple Computer, Network General, and Cisco Systems gave her opportunities to troubleshoot real-world network design problems and to develop a practical methodology for enterprise network design. Priscilla was one of the developers of the Cisco Internetwork Design course and the creator of the Designing Cisco Networks course and is a CCNP and CCDP. Priscilla currently teaches computer networking at Southern Oregon University.