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Introduction xx
Part I Framing the Problem
Chapter 1 Business and Technology 1 Business Drives Technology 2 The Business Environment 2 The Big Picture 3 The Competition 4 The Business Side of the Network 5 Technologies and Applications 5 Network Evaluation 6 The Network''s Customers 6 Internal Users 7 External Users 8 Guest Users 9 Technology Drives Business 9
Part II Business-Driven Design
Chapter 2 Designing for Change 11 Organic Growth and Decline 12 Mergers, Acquisitions, and Divestments 14 Centralizing Versus Decentralizing 15
Chapter 3 Improving Business Operations 19 Workflow 19 Matching Data Flow and Network Design 20 Person-to-Person Communication 21 Person-to-Machine Communication 21 Machine-to-Machine Communication 22 Bringing It All Together 23 BYOD 24 BYOD Options 24 BYOD Design Considerations 27 BYOD Policy 28 Business Continuity 29 Business Continuity Versus Disaster Recovery 29 Business Continuity Planning 30 Business Continuity Design Considerations 31 Summary 33
Part III Tools of the Trade
Chapter 4 Models 35 The Seven-Layer Model 36 Problems with the Seven-Layer Model 38 The Four-Layer Model 38 Iterative Layering Model 39 Connection-Oriented and Connectionless 41 A Hybrid Model 42 The Control Plane 43 What Am I Trying to Reach? 43 Where Is It? 44 How Do I Get There? 45 Other Network Metadata 46 Control Plane Relationships 46 Routing 46 Quality of Service 48 Network Measurement and Management 49 Interaction Between Control Planes 49 Reactive and Proactive 51 The Waterfall Model 53 Places in the Network 54 Summary 56
Chapter 5 Underlying Support 57 Questions You Should Ask 57 What Happens When the Link Fails? 57 What Types of Virtualization Can Be Run Over This Link? 58 How Does the Link Support Quality of Service? 59 Marking Packets 59 Queues and Rate Limiters 59 Speeds and Feeds Versus Quality of Service 60 Spanning Tree 61 TRILL 62 TRILL Operation 62 TRILL in the Design Landscape 64 TRILL and the Fabrics 65 Final Thoughts on the Physical Layer 65
Chapter 6 Principles of Modularity 67 Why Modularize? 68 Machine Level Information Overload 68 Machine Level Information Overload Defined 69 Reducing Machine Information Level Overload 71 Separating Complexity from Complexity 72 Human Level Information Overload 73 Clearly Assigned Functionality 74 Repeatable Configurations 75 Mean Time to Repair and Modularization 75 How Do You Modularize? 77 Topology and Reachability 77 Aggregating Topology Information at Router B 78 Aggregating Reachability Information at Router B 78 Filtering Routing Information at Router B 79 Splitting Failure Domains Horizontally and Vertically 79 Modularization and Optimization 81 Summary 82
Chapter 7 Applying Modularity 83 What Is Hierarchical Design? 83 A Hub-and-Spoke Design Pattern 84 An Architectural Methodology 85 Assign Each Module One Function 85 All Modules at a Given Level Should Share Common Functionality 86 Build Solid Redundancy at the Intermodule Level 87 Hide Information at Module Edges 88 Typical Hierarchical Design Patterns 89 Virtualization 90 What Is Virtualization? 90 Virtualization as Vertical Hierarchy 93 Why We Virtualize 93 Communities of Interest 94 Network Desegmentation 94 Separation of Failure Domains 94 Consequences of Network Virtualization 95 Final Thoughts on Applying Modularity 96
Chapter 8 Weathering Storms 97 Redundancy as Resilience 98 Network Availability Basics 98 Adding Redundancy 99 MTTR, Resilience, and Redundancy 100 Limits on Control Plane Convergence 100 Feedback Loops 102 The Interaction Between MTTR and Redundancy 103 Fast Convergence Techniques 104 Detecting the Topology Change 104 Propagating Information About the Change 105 Calculating the New Best Path 106 Switching to the New Best Path 107 The Impact of Fast Convergence 107 Fast Reroute 108 P/Q Space 109 Loop-Free Alternates 110 Remote Loop-Free Alternates 110 Not-Via Fast Reroute 111 Maximally Redundant Trees 113 Final Thoughts on Fast Reroute 115 The Human Side of Resilience 115
Chapter 9 Securing the Premises 117 The OODA Loop 118 Observe 119 Orient 122 Decide 124 Act 125 Brittleness 125 Building Defense In 126 Modularization 128 Modularity, Failure Domains, and Security 128 Modularity, Complexity, and Security 128 Modularity, Functionality, and Security 129 Resilience 129 Some Practical Considerations 129 Close a Door, Open a Door 129 Beware of Virtualization 131 Social Engineering 131 Summary 132
Chapter 10 Measure Twice 133 Why Manage? 133 Justifying the Cost of the Network 134 Planning 135 Decreasing the Mean Time to Repair 136 Increasing the Mean Time Between Mistakes 136 Management Models 137 Fault, Configuration, Accounting, Performance, and Security 137 Observe, Orient, Decide, and Act (OODA) 138 Deploying Management 140 Loosen the Connection Between Collection and Management 140 Sampling Considerations 141 Where and What 142 End-to-End/Network 142 Interface/Transport 143 Failure Domain/Control Plane 143 Bare Necessities 144 Summary 145
Part IV Choosing Materials
Chapter 11 The Floor Plan 147 Rings 147 Scaling Characteristics 147 Resilience Characteristics 149 Convergence Characteristics 151 Generalizing Ring Convergence 154 Final Thoughts on Ring Topologies 155 Full Mesh 155 Clos Networks 157 Clos and the Control Plane 159 Clos and Capacity Planning 160 Partial Mesh 161 Disjoint Parallel Planes 162 Advantages of Disjoint Topologies 163 Added Complexity 164 The Bottom Line 164 Divergent Data Planes 165 Cubes 166 Toroid Topologies 167 Summary 169
Chapter 12 Building the Second Floor 171 What Is a Tunnel? 171 Is MPLS Tunneling? 173 Fundamental Virtualization Questions 175 Data Plane Interaction 176 Control Plane Considerations 177 Control Plane Interaction 177 Scaling 178 Multicast 179 Security in a Virtual Topology 180 MPLS-Based L3VPNs 182 Operational Overview 182 Fundamental Questions 185 The Maximum Transmission Unit 185 Quality of Service 186 Control Plane Interaction 186 Scaling 187 Multicast 188 Security in MPLS-Based L3VPNs 188 MPLS-Based L3VPN Summary 188 VXLAN 189 Operational Overview 189 Fundamental Questions 190 Control Plane Interaction 190 Scaling 190 VXLAN Summary 191 Summary 191
Chapter 13 Routing Choices 193 Which Routing Protocol? 194 How Fast Does the Routing Protocol Converge? 194 Is the Routing Protocol Proprietary? 196 How Easy Is the Routing Protocol to Configure and Troubleshoot? 197 Which Protocol Degrades in a Way That Works with the Business? 198 Which Protocol Works Best on the Topology the Business Usually Builds? 199 Which Protocol is Right? 200 IPv6 Considerations 202 What Is the Shape of the Deployment? 202 How Does Your Deployment Grow? 202 Topological Deployment 203 Virtual Topology Deployment 203 Where Are the Policy Edges? 203 Routing Protocol Interaction with IPv6 204 IS-IS Interaction with IPv6 204 OSPF Interaction with IPv6 205 EIGRP Interaction with IPv6 206 Deploying BGP 206 Why Deploy BGP? 207 Complexity of Purpose 207 Complexity of Place 208 Complexity of Policy 208 BGP Deployment Models 209 iBGP Edge-to-Edge (Overlay Model) 209 iBGP Core 210 eBGP Edge-to-Edge (Core and Aggregation Model) 211 Summary 212
Chapter 14 Considering Complexity 213 Control Plane State 213 Concepts of Control Plane State 214 Network Stretch 215 Configuration State 217 Control Plane Policy Dispersion 218 Data Plane State 220 Reaction Time 223 Managing Complexity Trade-offs 225
Part V Current and Future Trends
Chapter 15 Network in Motion 227 The Business Case for Mobility 228 A Campus Bus Service 228 A Mobile Retail Analysis Team 229 Shifting Load 230 Pinning the Hard Problems into Place 230 Mobility Requires State 231 Mobility Requires Speed 231 State Must Be Topologically Located 232 State and the Network Layers 233 IP-Centric Mobility Solutions 234 Identifier-Locator Network Protocol (ILNP) 235 Locator Identifier Separation Protocol (LISP) 237 Mobile IP 238 Host Routing 239 Mobile Ad-Hoc Networks (MANET) 240 Dynamic DNS 242 Final Thoughts on Mobility Solutions 243 Remote Access Solutions 244 Separate Network Access from Application Access 244 Consider Cloud-Based Solutions 24