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.Promotional Information
The mission of Top-Down Network Design, Second Edition, is to
teach a practical methodology for designing enterprise networks
that are reliable, secure, and manageable. Like the popular first
edition, published by Cisco Press in 1998, this book teaches a
network design methodology that is based on structured systems
analysis techniques that revolutionized software development
projects back in the 1970s and 1980s, but updated to reflect new
priorities and technologies. The book begins by describing the
design methodology, as it has been adapted to fit modern network
design, with the topics being taught in the order that design tasks
should be accomplished. Case studies and examples are included to
help the reader understand how to successfully complete a design
project that fulfills a customer's requirements. Changes in the
business world have resulted in technological adjustments to
typical enterprise networks. The author emphasizes design with the
following four business goals that have emerged or re-emerged as
top-priority requirements for network designs in mind; an increased
need for security, for resilience, for project prioritization based
on business goals, and a need to support mobile users.
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.