Art of Network Architecture, The: Business-Driven Design, 1st edition
Published by Cisco Press (April 2, 2014) © 2014
- Russ White
- Denise Donohue
- Available for purchase from all major ebook resellers, including InformIT.com
The Art of Network Architecture is the first book that places business needs and capabilities at the center of the process of architecting and evolving networks, where it belongs. Three pioneering network architects show how to evaluate both business and application requirements from a network designer’s perspective, identifying crucial upfront questions that can help the reader shape networks that support current business strategy and provide flexibility for the future.
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 245
   Keep Flexibility as a Goal 246
   Consider Total Cost 248
   Consider Making Remote Access the Norm 248
What Solution Should You Deliver? 249
Chapter 16 On Psychologists, Unicorns, and Clouds 251
A Cloudy History 252
This Time It’s Different 254
What Does It Cost? 255
What Are the Risks? 256
What Problems Can Cloud Solve Well? 257
What Services Is Cloud Good at Providing? 258
   Storage 258
   Content Distribution 259
   Database Services 260
   Application Services 260
   Network Services 260
Deploying Cloud 261
   How Hard Is Undoing the Deployment? 261
   How Will the Service Connect to My Network? 261
   How Does Security Work? 262
   Systemic Interactions 262
Flying Through the Cloud 262
   Components 263
Looking Back Over the Clouds 264
Chapter 17 Software-Defined Networks 265
Understanding SDNs 265
   A Proposed Definition 265
   A Proposed Framework 266
       The Distributed Model 267
       The Augmented Model 268
       The Hybrid Model 269
       The Replace Model 271
       Offline Routing/Online Reaction 272
       OpenFlow 274
       Objections and Considerations 276
   Conclusion 281
Software-Defined Network Use Cases 281
   SDNs in a Data Center 281
       What OpenFlow Brings to the Table 281
       Challenges to the OpenFlow Solution 283
   SDNs in a Wide-Area Core 283
Final Thoughts on SDNs 285
Chapter 18 Data Center Design 287
Data Center Spine and Leaf Fabrics 287
   Understanding Spine and Leaf 288
   The Border Leaf 291
   Sizing a Spine and Leaf Fabric 291
       Speed of the Fabric 291
       Number of Edge Ports 292
       Total Fabric Bandwidth 293
   Why No Oversubscription? 294
The Control Plane Conundrum 295
   Why Not Layer 2 Alone? 295
   Where Should Layer 3 Go? 296
       Software-Defined Networks as a Potential Solution 298
Network Virtualization in the Data Center 299
Thoughts on Storage 299
Modularity and the Data Center 300
Summary 301
Â
9781587143755Â Â TOCÂ Â 3/12/2014
Â
Need help? Get in touch