What are the various concepts to be taken into consideration when creating a software architecture, what are the different types of architecture and when to apply what to a business scenario

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Architecture Concepts
Principles, Types, Views, Components, Agile

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Agenda
• Principles
• Types
• Views
• Components
• Architecture to Design
• Agile Architecture

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Architecture Principles
• Separation of concerns
• Points of failure
• Scalability
• Access control
• Architecture Styles (types of architecture, event driven,
process centric)
• Segregation

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Example – Shopping Site
Purchase
Items
Product
Catalogue
Payment
Members
Support
Loyalty
Fulfilment
Despatch
Receipt

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Separation of Concerns
• Each Feature must be addressed
by a single architectural
component
• One component may address
multiple features a single feature
should not be managed by
multiple components.
• If multiple components manage a
feature they should be bundled
together as a ‘package’ and
treated as a single component
(note if you end up with only 1
component in your system it is no
longer architecture)
CRM
Member Support
Workflow
Publish Product
Product Catalogue
Workflow
Workflow
Re-use

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Local Log
Points Of Failure
• Number of components that need to
fail for the entire system to shut down
• Larger the points of failure the more
stable the overall architecture
• Usually has a trade off with
performance
• Use Asynchronous interfaces to
reduce failure points
• Use Hardware redundancy to provide
for switchover
• Clustering (hot switchover)
• DR Site (cold switchover)
• Protect ‘sensitive’ components from
overloading
Order
Booking
Payment
Audit
Logging
Payment
Gateway (3rd
Party)
Order
Booking Payment
Audit
Logging
Payment
Gateway (3rd
Party)
Local Log
Drip Feed

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Workload/Usage Patterns
• Define peak/off peak
patterns and expected
‘surges’
• Project expected growth
over period of time
• Provide for capacity to
absorb peak usages
• Provide economically viable
solution
• Pattern could be Users,
Transactions, Data Loading,
Processing
• Scale Out when
• Peaks are for short periods of
time
• One time surge (such as start-
up)
• Budgets prevent large
investments in hardware and
licenses
• Scale Up when
• There is a predictable growth
in volumes
• Growth patterns do not have
significant peaks and troughs
• Budgets support initial
overcapacity

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Segregation
• Need to decouple component
• High resource usage
• Scale out a high usage component
• Availability issues
• Security Concerns
• Example
• Reporting/Data warehousing
• External Access
• Workflow
Time
Volume
Data Feed

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Architecture Types
• Three Tier
• Service Orientation
• Cloud Computing
• Event Driven
• High Throughput
• No SQL
• Map Reduce

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Three Tier
• Default type and most commonly use
• Applies the Model View Controller Pattern
• Model
• Encapsulates Application State
• Responds to Queries
• Exposes Functionality
• Notifies Changes
• View
• Renders models
• Requests for updates
• Sends user actions to controller
• Allows selection by controller
• Controller
• Defines application behaviour
• Maps user action to model updates
• Selects view for response
• Separate for each functionality

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Service Orientation
• Provide a set of services rather than interfaces to external
applications
• Ability to monitor and manage the resource usage by services
• Ability to allocate system resources based upon simple rules
• Service has a contract – key elements of that contract. Same
service can have multiple contracts
• Who can call
• For that caller, what it need to pass
• For that caller – what will be response
• When caller can expect response
• What will be communication channel
• Operates on a publish-subscribe model
• May be aligned with commercial models which require specific
usage data to be maintained

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Component 1
Event Driven
• Used where the system is part of a partially or fully automated
operation or a real time loop
• Operates on a throw—catch model
• Usually built in a single tier with interfaces with other systems
for Human Machine Interface (such as mobile alerts, emails)
• Decouples application and component interfaces
• Internal interfaces through components raising and processing
events
• Typical example would be system monitoring and management
Event
Raise
Input
Component 2
Catch

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Cloud Computing
• Hosted environment provided by vendors for
• Web Sites
• Databases
• File Services
• Images and Videos
• Removes need for administrating site and managing scaling
• Different architectural components may be deployed on different
clouds
• Provides elasticity in capacity building and management
• Commercials depend upon nature of site and type (public/private) of
usage (Rate Controls)
• Private clouds help reduce capital budgets with shared services
• Typical Usages
• Mobile Applications
• Customer Services
• Business Intelligence

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No SQL Databases
• No SQL databases support
unstructured data by replacing
RDBMS concept of row with
‘Document’(Mostly JSON)
• Schema is not enforced by
database, consuming
applications are expected to
deal with structure
• Data is mostly distributed
across some kind of network
file system
• Every piece of data has
(Minimum 3)
Conceptual View of
NO SQL
Node1 Node 2 Node n

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Virtual Dataset
Node1 Node 2 Node n
Master Controller
Node
Map Reduce Architecture
• Map-Reduce architecture is
built for handling terabyte –
petabyte data load using
cluster of cheap commodity
nodes
• Algorithms are expressed as
two functions. Map function
travels over network where
data resides and applies on
data
• Final results are combined
back using reduce function
• Our own IP – Data Extraction
Platform (DEP) is built using
Map-Reduce which provides
grid scale capability to
handle massive data loads

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Architecture Views
• Overview
• Business
• Application
• Technical
• Information
• Deployment

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Structured Data
Content
Distribution
Mining
Performance
Applications
Products
Tools
Interfaces
Mapping
Enterprise Architecture
Enterprise
Architecture
Business
Organization Structure
Operations
Locations
O/S
Middleware
Instrumentation
Integration
Failover
Scaling
Patterns
Distribution
Support infrastructure
Benchmarks
Disaster Recovery

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Business Architecture
CEO
Operations Finance Vendor Mgmt Sales
Members
Support
Editing
Receipts
Banking
investments
Accounting
Acquisition
Delivery
Payments
Payments
Promotions
Events
Loyalty Mgmt
Products Data Analysis

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Application Architecture
Website
Content
Management
Workflow
CRM Payment
Gateway
BPM
Vendors

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Application Architecture
Data Layer
Business Layer
Db Server OLAP Db
Content
Server
User Interface Layer
Web Client App 3rd Party
CRM Content Workflow
Interface
BPM

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Information Architecture
Main Database
(Entities and
Relations)
DR Site
Configuration
Regional
Databases
Content Server
Content BackupPurchase Payment Pricing Delivery
Customer C R U R U R U
Product R C R U R U

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Technical Architecture
O/S
App Server
Web Site
Content Server
Workflow
LDAP
O/S
Database Server
O/S
BPM
External
Interfaces
O/S
Mail Server

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Deployment Architecture
Members
Partners
Employees
VPN
Scale Up
Scale Out
Server Farm

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Architecture Components
• Independently maintained software
• Addresses one or more functional and non-functional
requirements
• Selection from a class of similar software on the basis of
• Compatibility with proposed stack
• Cost
• Fitment with client requirements
• Common Components
• Portal
• Workflow
• BPM
• ETL
• Document Management
• Rules Engine
• Security
• Systems Management

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Common Architecture Components
• Products and tools regularly used in systems
• List of most popular components
• Integration & Workflow
• Document Management
• Rules Engine
• Security
• System Management
• Business Intelligence

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Overview
• Independently maintained software
• Addresses one or more functional and non-functional
requirements
• Selection from a class of similar software on the basis of
• Compatibility with proposed stack
• Cost
• Fitment with client requirements

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Workflow
• Products which manage processes within an organisation
• Generates tasks on completion of an event
• Has capability to determine which task to initiate
depending upon configurable parameter
• May be bundled with CRM and Document Management
products
• Primarily meant to handle manual tasks and does not scale
well to large transaction volumes

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Integration
• Define and manage external interfaces
• Manage processes across multiple systems or organisations
• Process integration defined through standard language
(such as BPEL or BPMN 2)
• Provide an Orchestration service to compose business
views from multiple sources
• Provide a highly configurable platform when dealing with
multiple partners or systems
• Can be implemented in conjunction with workflow engines
• Not to be used for high volume data processing (use ETL
tools instead) for integration or data loading

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Document Management
• Repository based tool to create, modify and publish documents
• Manages access through Access Control Lists or third party Role
Based Access Control systems
• Maintains history of changes and can produce specific version
• May include multiple channels including RSS feeds
• Significantly improves productivity
• Can extend to maintain content, specially for web based
applications
• Manage feeds from external devices (scanners, cameras etc)
• Meant for stable process flows, has problems when document
management processes change frequently
• Not very cost effective for small volumes

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Rules Engine
• Define and manage complex business rules with high
transaction volumes
• Ideally suited for STP type of requirements
• Can be combined with Workflow or BPM engine to
determine process direction
• May be used to make complex rule driven calculations
• Expensive and process hungry

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Security
• Manage access to data and functions
• Three aspects
• Identity Management – Issue/update password, smart card,
biometrics
• Authentication – Verify identity of user
• Access Control – Determine access to functions and data
• Each aspect may be addressed by a different product
• Regulatory requirements regarding privacy at local and
country level
• Additional measures would include firewalls, certification
and anti-virus solutions

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System Management
• System Monitoring and Management
• Instrumentation for escalating key events
• Performance monitoring and diagnostics
• Compatibility with application and product
instrumentation
• Optimizes hardware and software resources
• Expensive to deploy and maintain

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Common Components
• Can be a library or published services
• Nature of services or methods provided
• Usage rules must be defined
• Typically fall into these categories
• Interface Patterns or Facades
• System Service Providers (Security, Access Control, Audit)
• File Management
• Instrumentation

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Architecture to Design
• Defining common components
• Constraints
• Design standards
• Defining master templates
• Coding standards,
• Risks – How mitigated
• Assumption

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Agile Architecture
• Solution Modelling
• Evolutionary Design
• NFR Management

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Solution Modelling
• Three Dimensional Models
• Business/Product/Service for which the software is used
• Features and Functionality which are provided by the software
• Technology and Configuration used to run the software
• Release objectives and scope set on one dimension
• Teams defined on another
• Product Backlog on the third

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F5
Traditional – Modelling
F1
F2
F3
F4
T1 T2 T3 T4 T5 T6 T7
Technologies

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F5
Agile Planning – Modelling
F1
F2
F3
F4
P1 P2 P3 P4 P5 P6 P7
Businesses/Products/Services

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Functional
Non-Functional
Evolutionary Design
Pre Sales
(Contract)
Application Architecture
Features Themes Story/Function Points
Non Functional Requirements
Functionality
Concepts, Standards
and Templates
Estimate, Staffing
Principles, Components
and Interfaces
Velocity, Productivity,
Buffers, Activities
Foundation
(Plan)
High Level Design
Epics Themes
Project
Backlog
Story Points
Sprint
(Actual)
Low Level Design
User StoriesBacklog
Story Points
Tasks
Estimate, Staffing
Velocity,
Activities
Actual
Dis
Assembly
Estimate
Velocity
Assign

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Example – Shopping Cart
Epic – Registered user searches for products for Purchase
User Stories
Search Select CheckoutLogin
High Level Design
Search Form
• Free Text Search
• Product Name,
Category, Size, Colour
and brand
Query Generator
• Create Query based
on selected
parameters
• Fetch Data
Saved Searches
• Parameter
• Value
Low Level Design
Wireframe Field Validations Query Generator
Interface
Save Searches
Retrieve Searches
Pre Sales
Release Planning
Release
Foundation
Sprint

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Agile Architecture
Data Layer
Business Layer
Db Server OLAP Db
Content
Server
User Interface Layer
Usability Themes
User Story 1 User Story 2
Maintainability Themes
Performance Themes
Task1Task2
Task1Task2Task3
Security ThemesEpic
User Story 3
Availability
Themes
QueryMemory/CPURendering
AuthenticationAccessControlDataFilter

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NFR Management
Features User Story Security Performance Usability Others
RBAC Data Filter Capacity Latency UI Preferences Menu
Feature 1 User Story 1 X X X X X X
User Story 2 X
User Story 3 X X X X X
Feature 2 User Story 4 X X
Feature 3 User Story 5 X X X
User Story 6 X X X
User Story 7 X X X X
Feature 4 User Story 8 X X
User Story 9 X X X
User Story 10 X X X X
Feature 5 User Story 11
User Story 12 X X X X
Implementation approach Template Component Service Optimise Db Template Template Template
Implemented by Story Story Story Activity Story Story Story

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Object
Model
Design Framework
User Interface Business Rules Data Management External Interfaces
Forms
Grids
Workflow
Validations
Stored Procedures/Triggers
Database
Content
Configuration
Protocols
Transport
Content/Payload
GenericProduct
Flex
Flash Browser YAWL
DROOLS
ANSI (Oracle/SQL Server)
File Services
Web Services REST/SOAP
Blaze
Server Interface
Model
Application
Objects
Logical Model
Group Model
Data
Model
Interface
Objects
Implement
Pagination
Actions
Process Flow
Work Flow
Rules
Transaction Manager
Persistence Manager
Interface Manager
File Manager
Eclipse for Modelling
BIRT over RDB
Custom Workflow YAWL TemplatesJBEAM
Calculations
Calculations

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