Simple Architectures for Complex Enterprises

by Sessions, Roger

• ISBN13: 9780735625785
• ISBN10: 0735625786
• Edition: 1st
• Format: Paperback
• Copyright: 2019-09-10
• Publisher: Microsoft Press

Summary

Slash the complexity that overwhelms large IT projects'”and improve return on investment and increase business agility. Learn a practical methodology for simplifying your IT architecture and improving results from an expert on enterprise architecture.

Author Biography

Roger Sessions is a well-known consultant and expert in the field of enterprise software architecture. He is a board member for the International Association of Software Architects (IASA), editor-in-chief of IASA's Perspectives journal, and a Microsoft MVP. He's written seven books, including Software Fortresses: Modeling Enterprise Architectures, and presented at dozens of conferences worldwide

Table of Contents

Acknowledgments	p. xiii
Introduction	p. xv
The Organization of This Book	p. xx
Find Additional Content Online	p. xxi
Support for This Book	p. xxi
Questions and Comments	p. xxii
The Question of Complexity
Enterprise Architecture Today	p. 3
Why Bother?	p. 3
Issue: Unreliable Enterprise Information	p. 4
Issue: Untimely Enterprise Information	p. 4
Issue: New Complex Projects Underway	p. 4
Issue: New Companies Being Acquired	p. 5
Issue: Enterprise Wants to Spin Off Unit	p. 5
Issue: Need to Identify Outsourcing Opportunities	p. 5
Issue: Regulatory Requirements	p. 5
Issue: Need to Automate Relationships with External Partners	p. 6
Issue: Need to Automate Relationships with Customers	p. 6
Issue: Poor Relationship Between IT and Business Units	p. 6
Issue: Poor Interoperability of IT Systems	p. 6
Issue: IT Systems Unmanageable	p. 7
The Value of Enterprise Architecture	p. 7
Common Definitions	p. 7
What Is Enterprise Architecture?	p. 8
Complexity in Enterprise Architectures	p. 10
The Zachman Framework for Enterprise Architectures	p. 15
The Open Group Architecture Framework	p. 20
Federal Enterprise Architecture	p. 26
Summary	p. 33
A First Look at Complexity	p. 35
Partitioning	p. 35
Executive Lunch	p. 35
Choir Rehearsal	p. 36
Emergency Responses	p. 37
Clothing Store	p. 38
Chess Games	p. 38
Children at Starbucks	p. 39
Rubik's Cube	p. 40
Five Laws of Partitions	p. 42
First Law: Partitions Must Be True Partitions	p. 42
Second Law: Partition Definitions Must Be Appropriate	p. 43
Third Law: Partition Subset Numbers Must Be Appropriate	p. 44
Fourth Law: Partition Subset Sizes Must Be Roughly Equal	p. 44
Fifth Law: Subset Interactions Must Be Minimal and Well Defined	p. 45
Simplification	p. 45
Iteration	p. 46
Summary	p. 52
Mathematics of Complexity	p. 53
Looking at Complexity	p. 54
Laws of Complexity	p. 58
Homomorphisms	p. 60
Controlling Complexity in Dice Systems	p. 61
Adding Buckets	p. 62
Partitioning	p. 65
Equivalence Relations	p. 67
Equivalence Classes	p. 71
Inverse Equivalence Relations	p. 72
Equivalence Relations and Enterprise Architectures	p. 73
Synergistic in Practice	p. 76
Removing Faces	p. 77
Removing Buckets	p. 79
Other Measures of Complexity	p. 80
Complexity in Theory and in Practice	p. 81
Summary	p. 83
The Quest for Simplification
The ABCs of Enterprise Partitions	p. 87
Review of the Mathematics	p. 87
Partitioning the Enterprise	p. 88
The ABCs of Enterprise Equivalence Classes	p. 89
ABC-Type Relationships	p. 90
Implementations and Deployments	p. 93
ABC Types	p. 95
Type Hierarchies	p. 96
Composition Relationships	p. 98
Partner Relationships	p. 99
Relationships and Partition Simplification	p. 100
Retail Operation, Again	p. 102
Summary	p. 106
SIP Process	p. 107
Overview	p. 107
Enterprise Architecture Evaluation	p. 108
Issue: Unreliable Enterprise Information	p. 109
Issue: Untimely Enterprise Information	p. 109
Issue: New Complex Projects Underway	p. 110
Issue: New Companies Being Acquired	p. 110
Issue: Enterprise Wants to Spin Off Unit	p. 111
Issue: Need to Identify Outsourcing Opportunities	p. 111
Issue: Regulatory Requirements	p. 112
Issue: Need to Automate Relationships with External Partners	p. 112
Issue: Need to Automate Relationships with Customers	p. 113
Issue: Poor Relationship Between IT and Business Units	p. 113
Issue: Poor Interoperability of IT Systems	p. 113
Issue: IT Systems Unmanageable	p. 114
Contraindications	p. 114
SIP Preparation	p. 115
Audit of Organizational Readiness	p. 115
Training	p. 116
Governance Model	p. 116
SIP Blend	p. 117
Enterprise-Specific Tools	p. 117
Partitioning	p. 118
Partition Simplification	p. 121
ABC Prioritization	p. 124
ABC Iteration	p. 127
Summary	p. 128
A Case Study in Complexity	p. 129
Overview of NPfIT	p. 129
Current Status of NPfIT	p. 132
The SIP Approach	p. 135
Summary	p. 145
Guarding the Boundaries: Software Fortresses	p. 147
Technical Partitions	p. 147
Autonomy	p. 152
Explicit Boundaries	p. 152
Partitioning of Functionality	p. 153
Dependencies Defined by Policy	p. 153
Asynchronicity	p. 153
Partitioning of Data	p. 154
No Cross-Fortress Transactions	p. 155
Single-Point Security	p. 156
Inside Trust	p. 156
Keep It Simple	p. 156
Summary	p. 157
The Path Forward	p. 159
Complexity: The Real Enemy	p. 160
Simplicity Pays	p. 161
A Philosophy of Simplicity	p. 164
A Review of the Book Content	p. 165
A Parting Message	p. 166
This Book at a Glance	p. 169
Mathematical Concepts	p. 169
Mathematical Definition of a Partition	p. 169
Five Laws of Partitions	p. 169
Measuring States in a System of Dice-Like Systems	p. 170
Homomorphism	p. 170
Equivalence Relations	p. 170
Inverse Equivalence Relations	p. 171
Partitions	p. 171
Partitioning Algorithm for Equivalence Relations	p. 171
Enterprise Architectural Concepts	p. 172
Preferred Definition of Enterprise Architecture	p. 172
Definition of Optimal Architecture	p. 172
Boyd's Law of Iteration	p. 172
Laws of Enterprise Complexity	p. 172
Synergistic and Autonomous	p. 173
SIP Concepts	p. 173
Definition of SIP	p. 173
The SIP Process	p. 173
ABC	p. 174
Software Fortress Model	p. 175
Three Styles of ABC Communications	p. 176
The SIP Mantra	p. 176
Index	p. 177
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