Russ White, Jeff Tantsura

Navigating Network Complexity (eBook, PDF)

Next-generation routing with SDN, service virtualization, and service chaining

• Format: PDF

Produktbeschreibung

Design your networks to successfully manage their growing complexity

Network professionals have often been told that today's modern control planes would simplify their networks. The opposite has happened: Technologies like SDN and NFV, although immensely valuable, are exacerbating complexity instead of solving it. Navigating Network Complexity is the first comprehensive guide to managing this complexity in both deployment and day-to-day operations.

Russ White and Jeff Tantsura introduce modern complexity theory from the standpoint of the working network engineer, helping you apply it to the practical problems you face every day. Avoiding complex mathematical models, they show how to characterize network complexity, so you can understand it and control it.

The authors examine specific techniques and technologies associated with network control planes, including SDNs, fast reroute, segment routing, service chaining, and cloud computing. They reveal how each of these affects network design and complexity and help you anticipate causes of failure in highly complex systems.

Next, they turn to modern control planes, examining the fundamental operating principles of SDNs, such as OpenFlow and I2RS, network and other service function virtualization, content distribution networks, Layer 2 fabrics, and service chaining solutions. You'll learn how each of these might both resolve and increase complexity in network design and operations and what you can do about it.

Coverage includes:

• Defining complexity, understanding its components, and measuring it
• Mastering a straightforward "state, speed, and surface" model for analyzing complexity
• Controlling complexity in design, deployment, operations, protocols, and programmable networks
• Understanding how complex network systems begin to fail and how to prevent failure
• Recognizing complexity tradeoffs in service virtualization and service chaining
• Managing new challenges of complexity in virtualized and cloud environments
• Learning why constructs such as hierarchical design, aggregation, and protocol layering work and when they work best
• Choosing the right models to contain complexity as your network changes

From start to finish, Navigating Network Complexity helps you assess the true impact of new network technologies, so they can capture more value with fewer problems.

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Produktdetails

• Verlag: Pearson ITP
• Seitenzahl: 320
• Erscheinungstermin: 5. November 2015
• Englisch
• ISBN-13: 9780133988079
• Artikelnr.: 44219935

Autorenporträt

Russ White began his network engineering career installing terminal emulation cards and inverse multiplexers in the United States Air Force. In 1996, he moved to Raleigh, N.C., to join Cisco Systems in the Technical Assistance Center (TAC) routing protocols team. From TAC, Russ moved to the global escalation team, and then into engineering, and finally into sales as a Distinguished Architect. He is currently a network architect working in the area of network complexity and large scale design, a member of the IETF Routing Area Directorate, an active speaker and writer, and active in the Internet Society.

He holds CCIE #2637, CCDE 2007:001, the CCAr, a Masters in Information Technology from Capella University, and a Masters in Christian Ministry from Shepherds Theological Seminary. He lives in Oak Island, N.C., with his wife and two children, and is currently a P.h.D student at Southeastern Baptist Theological Seminary.

Jeff Tantsura started his network engineering career in early 1990s at a small ISP as system/network administrator, later working for bigger ISPs where he was responsible for network design and architecture, vendor selection. Currently Jeff is heading Technology Strategy Routing at Ericsson as well as chairing IETF Routing Working Group. Jeff holds MSc in Computer Science and Systems Analysis from University of Georgia and Executive Certificate of Business Excellence from Haas School of Business, Berkeley.

He also holds CCIE R&S #11416 and Ericsson Certified Expert IP Networking #8.

Jeff lives in Palo Alto, CA, with his wife and youngest child.

Inhaltsangabe

Introduction . . . . . . . . . . . . xvii
    How This Book Is Organized . . . . . . . xvii
Chapter 1: Defining Complexity . . . . . . . . . 1
    What Is Complexity? . . . . . . . . . 3
        Anything I Don’t Understand . . . . . . 3
        Anything with a Lot of Parts . . . . . . . 5
        Anything for Which There Is More State Than Required to
        Achieve a Goal . . . . . . . . . 9
        Unintended Consequences . . . . . . 11
    Why So Much Complexity? . . . . . . . . 13
        Future Extensions versus New Protocols . . . . 16
        Unexpected Errors . . . . . . . . 17
    Why Not Build Infinitely Complex Systems? . . . . . 18
        Quick, Cheap, and High Quality: Choose Two . . . 20
        Consistency, Availability, and Partition Tolerance:
        Choose Two . . . . . . . . . 21
    Journey into the Center of Complexity . . . . . . 22
Chapter 2: Components of Complexity . . . . . . . 25
    Network Convergence . . . . . . . . . 26
        Path Vector: A BGP Example . . . . . . 26
        Distance Vector: An EIGRP Example . . . . . 28
        Link State: OSPF and IS-IS Convergence . . . . 30
    State . . . . . . . . . . . . 31
        Amount of Information . . . . . . . 32
        An Example of State Failure in the Real World . . . 33
        Final Thoughts on State . . . . . . . 34
    Speed . . . . . . . . . . . . 35
        The Network That Never Converges . . . . . 35
        The Flapping Link . . . . . . . . 37
        Final Thoughts on Speed . . . . . . . 38
    Surface . . . . . . . . . . . . 38
    The Hourglass Model . . . . . . . . . 41
    Optimization . . . . . . . . . . . 44
    A Final Thought . . . . . . . . . . 46
Chapter 3: Measuring Network Complexity . . . . . . 47
    Some Measures of Network Complexity . . . . . 49
        Network Complexity Index . . . . . . 49
        Modeling Design Complexity . . . . . . 51
        NetComplex . . . . . . . . . 53
    Organized Complexity . . . . . . . . . 55
    Is This a Waste of Time? . . . . . . . . . 58
        A Final Thought . . . . . . . . . . 58
Chapter 4: Operational Complexity . . . . . . . . 61
    Exploring the Problem Space . . . . . . . . 61
        The Cost of Human Interaction with the System . . . 61
        Policy Dispersion versus Optimal Traffic Handling . . 66
    Solving the Management Complexity Problem . . . . 69
        Automation as a Solution to Management Complexity . 69
        Modularity as a Solution to Management Complexity . 72
        Protocol Complexity versus Management Complexity . 74
        A Final Thought . . . . . . . . . . 77
Chapter 5: Design Complexity . . . . . . . . . 79
    Control Plane State versus Stretch . . . . . . . 81
        Aggregation versus Stretch . . . . . . . 83
        Traffic Engineering . . . . . . . . 85
        State versus Stretch: Some Final Thoughts . . . . 87
    Topology versus Speed of Convergence . . . . . . 88
        Ring Topology Convergence . . . . . . 88
        Redundancy versus Resilience . . . . . . 90
        Topology versus Speed of Convergence:
        Some Final Thoughts . . . . . . . 93
    Fast Convergence versus Complexity . . . . . . 94
        Improving Convergence with Intelligent Timers: Talk Faster . . . .
. . . . . 96
        Removing Timers from Convergence: Precompute . . 99
        Working around Topology: Tunneling to the Loop-Free
        Alternate . . . . . . . . . 101
        Some Final Thoughts on Fast Convergence . . . 104
    Virtualization versus Design Complexity . . . . . 106
        Functional Separation . . . . . . . 108
        Forwarding Plane Complexity . . . . . . 109
        Control Plane Complexity . . . . . . 109
        Shared Fate Risk Groups . . . . . . . 111
    A Final Thought . . . . . . . . . . 111
Chapter 6: Managing Design Complexity . . . . . . 113
    Modularity . . . . . . . . . . . 113
        Uniformity . . . . . . . . . 114
        Interchangeable Modules . . . . . . . 120
        How Modularity Attacks the Complexity Problem . . 121
    Information Hiding . . . . . . . . . 122
        Aggregation . . . . . . . . . 122
        Failure Domains and Information Hiding . . . . 126
        Final Thoughts on Information Hiding . . . . 128
    Models . . . . . . . . . . . 129
        Waterfall . . . . . . . . . . 129
        Places in the Network . . . . . . . 131
        Hierarchical . . . . . . . . . 132
        UML . . . . . . . . . . . 134
    A Final Thought . . . . . . . . . . 136
Chapter 7: Protocol Complexity . . . . . . . . 137
    Flexibility versus Complexity: OSPF versus IS-IS . . . . 138
    Layering versus Protocol Complexity . . . . . . 141
        The Seven-Layer Model . . . . . . . 143
        The Four-Layer Model . . . . . . . 146
        The Iterative Model . . . . . . . . 147
        Protocol Stacks and Design . . . . . . 148
    Protocol Complexity versus Design Complexity . . . . 149
        Microloops and Fast Reroute . . . . . . 149
        EIGRP and the Design Conundrum . . . . . 158
    Final Thoughts on Protocol Complexity . . . . . 162
Chapter 8: How Complex Systems Fail . . . . . . . 163
    Feedback Loops . . . . . . . . . . 164
        Positive Feedback Loops in Network Engineering . . 169
        Speed, State, and Surface: Stability in the
        Network Control Plane . . . . . . . 174
    Shared Fate . . . . . . . . . . . 177
        Virtual Circuits . . . . . . . . . 177
        TCP Synchronization as a Shared Fate Problem . . 179
    A Final Thought . . . . . . . . . . 181
        Thoughts on Root Cause Analysis . . . . . 181
        Engineering Skills and Failure Management . . . 182
Chapter 9: Programmable Networks . . . . . . . 185
    Drivers and Definition . . . . . . . . . 186
        Business Drivers . . . . . . . . 186
        The Ebb and Flow of Centralization . . . . . 188
        Defining Network Programmability . . . . . 191
    Use Cases for Programmable Networks . . . . . 193
        Bandwidth Calendaring . . . . . . . 193
        Software-Defined Perimeter . . . . . . 196
    Programmable Network Interfaces . . . . . . 200
    The Programmable Network Landscape . . . . . 201
        OpenFlow . . . . . . . . . . 202
        YANG . . . . . . . . . . 204
        Path Computation Element Protocol . . . . . 207
        Interface to the Routing System . . . . . 210
    A Final Thought . . . . . . . . . . 212
Chapter 10: Programmable Network Complexity . . . . . 215
    The Subsidiarity Principle . . . . . . . . 216
    Policy Management . . . . . . . . . 217
        Policy Dispersion . . . . . . . . 220
        Policy Consistency . . . . . . . . 222
        Policy Complexity . . . . . . . . 223
    Surface and the Programmable Network . . . . . 224
    Impact on Failure Domains . . . . . . . . 226
        Wide Area Failure Domains . . . . . . 227
        Data Center Failure Domains . . . . . . 228
        Application to Control Plane Failure Domain . . . 229
        Controller to Controller Failure Domain . . . . 229
        Final Thoughts on Failure Domains . . . . . 229
    A Final Thought . . . . . . . . . . 230
Chapter 11: Service Virtualization and Service Chaining . . . . 233
    Network Function Virtualization . . . . . . . 234
        NFV: A Use Case . . . . . . . . 236
    Service Chaining . . . . . . . . . . 242
        Service Function Chaining . . . . . . 243
        Segment Routing . . . . . . . . 245
    A Final Thought . . . . . . . . . . 248
Chapter 12: Virtualization and Complexity . . . . . . 249
    Policy Dispersion and Network Virtualization . . . . 250
        State and Service Chaining . . . . . . 253
        State and Optimization . . . . . . . 254
        Surface and Policy Interaction . . . . . . 255
        Surface and Policy Proxies . . . . . . 255
    Other Design Considerations . . . . . . . 256
        Coupling and Failure Domains . . . . . . 257
        Troubleshooting . . . . . . . . 260
    The Orchestration Effect . . . . . . . . 262
    Managing Complexity . . . . . . . . . 264
    A Final Thought . . . . . . . . . . 266
Chapter 13: Complexity and the Cloud . . . . . . . 267
    Where Does the Complexity Live? . . . . . . 268
        Cloud Centric . . . . . . . . . 269
        Vendor Centric . . . . . . . . . 270
        Network Centric . . . . . . . . 271
        Is There a “Right Way?” . . . . . . . 271
    Centralize What? . . . . . . . . . . 272
    Cloudy Complications . . . . . . . . . 273
        Security . . . . . . . . . . 273
        Data Portability . . . . . . . . 276
    A Final Thought . . . . . . . . . . 277
Chapter 14: A Simple Ending . . . . . . . . . 279
    Defining Complexity . . . . . . . . . 279
        Difficult to Understand . . . . . . . 280
        Unintended Consequences . . . . . . 280
        Large Numbers of Interacting Parts . . . . . 280
        What Makes Something “Too Complex”? . . . 281
    Complexity Is a Tradeoff . . . . . . . . 282
    Modeling Complexity . . . . . . . . . 284
    Managing Complexity in the Real World . . . . . 286
        Don’t Ignore Complexity . . . . . . . 286
        Find a Model to Contain the Complexity . . . . 287
    A Final Thought . . . . . . . . 288
TOC, 9780133989359, 10/28/2015