System and Software Architectures Ed Green

System and Software Architectures

Ed GreenPennsylvania State

UniversityThe Abington College

April 10, 2023

April 10, 2023 System and Software Architectures 2

Types of Architectures Physical – reflects the hardware elements Logical – reflects the software elements Network – reflects the communications

topology elements Application – reflects the decomposition of

each application into objects and components Data – models the enterprise based upon its

data subjects Interface – describes how key architectural

components interact or interoperate with each other

Integration – reflects the combination of physical, logical, network, and applications into one common view


Understanding the Environment Each architecture element must be

well understood– Components of each will help to develop

the integrated picture• Some components will appear in more than one

depiction• Inclusion may be required for clarity

Each kind of architecture must be understood “in context”– Need a frame of reference– Architectures do not exist in a vacuum – Dependence on business framework and

architecture


Architecture – a Definition Technical blueprint that illustrates the

deployment of services across a topology

Description of the interoperation among the service components

Identification of specific products that can be or are being used to implement the blueprint

Process of specific steps to be achieved to implement the technical blueprint


Opening Round – Some Definitions Topology – the depiction showing where

component elements of the architecture are located

Component – an identifiable part of the architecture

Application – an information system that is intended to solve a specific problem– Architecture-oriented– Enterprise-oriented

System – set of things working together to achieve a goal or objective– Information System – a set of computer modules

working in concert with people to meet a goal/objective of providing accurate and timely information that supports business analysis and/or decision making


Elements of Architecture Services

– Whatservices?

Topology– Located

where?

Process– Done how?

CommunicationServices

Operating System Services

Operating

System

Services

Hardware

Hardware

Security Services

Security

Service

System

&

Network

Mgmt

Services

System and Network Management Services

ConnectivityServices

Object ManagementServices

DistributionSupport Services

Physical Network

Subnetworking

Signalingand Control

Transport

Common Transport Semantics

Network Services

SECURITY

SERVICES

Applicationand

ApplicationEnablingServices

Distributed SystemsServices

Data InterchangeServices

Data Management Services

PresentationServices

Applications

Application DevelopmentServices

Object/ComponentServices

ApplicationWorkgroup

andCollaboration

Services

Foun

datio

n

Ser

vice

s


Network Architecture


Network Architecture – Backbone of the Architecture Explains the communications configuration

– What elements will be used for communication? Defines the topology of the architecture

– Where will these communications be located? Describes the routing

– How will data get from one node to the next?– Considers alternatives

• Transportation model

Addresses protocols– What is the communications mechanism?– Are multiple protocols used and is translation

needed?


Transportation Model “Import” from Operations Research

– Developed originally to optimize routing of freight hauling vehicles (trains and trucks)

– Represents a realistic algorithm set that directs transports to the path of least obstruction

• Minimum Traffic• Minimum delays

Example– A shipment of Volkswagens arrives at the Port of

Baltimore. These cars are to be shipped to various locations across the United States, including Pittsburgh, Fort Wayne, Kansas City, Denver, and Missoula. What is the optimal route?

– At each city, what is the best route to the next stop based on all routing conditions?

• Traffic• Construction• Weather


Applying the Transportation Model NORNE, a large energy services

company, has business centers located in Baltimore, Pittsburgh, Fort Wayne, Kansas City, Denver, and Missoula. Payroll for the entire company is processed at the Baltimore computer center. Individual time and attendance data is collected for employees at individual locations and then forwarded to Baltimore. Since payroll is a time critical application, time and attendance data must arrive in a timely manner.


Applying the Transportation Model

Which route will the data take?


Applying the Transportation Model Route not predictable in advance

– Will vary based on conditions Will follow “path of least resistance”

– ALL network managers work to minimize latency and maximize throughput

Data will depart from a given node with– Next node identified– General itinerary

General itinerary identified upon arrival at destination– Routing re-planned should conditions

warrant


Components of Network Architectures Routers – a physical or logical device that

determines the next network point to which a packet should be forwarded– Connected to at least two networks– Decision based on current understanding of

network state• Table of routing alternatives and current conditions

– Located at any gateway Gateway – the place where one network

or network segment meets another Switch – a physical or logical device that

redirects a packet from one network segment to another


Components of Network Architecture Bandwidth – the capacity of a

network measured in terms of throughput rate– Gigabits per second

TCP/IP communications language of the internet

Packet – the “data unit” that is transported from one node to another


Network Architecture – Showing the Components

Mainframe Router

LocalServers

Router

Local ServersWith Clients


Network Architecture – Showing the Topology

Mainframe Router

LocalServers

Router Local Servers

With Clients


Network Architecture – Mapping to ProductsNetwork

NodeCompone

ntVendor Model Technical

Spec’s

Sh

ou

ld h

ave

ven

dor’

s U

RL


Physical Architecture


Physical Architecture – Computers and Things Identifies the hardware components

that are used in the architecture Also identifies various sub-components

– Workstations and “dumb” terminals– Secondary storage

• Disks• Tapes• RAID• Optical storage

– Communications processors Describes component connectivity May include key technical specifications


Physical Architecture – What is Involved? Data center components Office environment

components– Includes integrated laboratory

components Central data collection

components Central display components


Physical Architecture – View of a Typical Environment

Clients

Web Server

ApplicationServers

Data Server


Physical Architecture in a Typical Enterprise

Factory

Office

Lab Stores


Physical Architecture – What it Really Involves What workstations or

terminals?– How many (of each)?

What server(s)?– How many?

What separate configurable items?– Disk– Tape– Printers– Monitors


Physical Architecture – The Keys Physical Architecture is not just a list of

computers Physical Architecture requires the

identification and specification of all separately configurable computer hardware components

Physical Architecture includes all physical components in Network Architecture

Physical Architecture must identify connectivity

Physical Architecture should be mapped to topology


Physical Architecture – The Keys Physical Architecture should

be based on capacity plan– Growth expectations included– Expansion understood

Physical Architecture should be based on guidelines and standards– Seek a common denominator– Embrace heterogeneity – before it

eats you alive


Physical Architecture – Mapping to ProductsNetwork

NodeCompone

ntVendor Model Technical

Spec’s

Sh

ou

ld h

ave

ven

dor’

s U

RL


Logical Architecture


Logical Architecture Shows the configuration of software

– Operating System(s)– Network Manager(s)

• Browsers

– Data and Database Manager(s)– Compilers/Interpreters– Service Utilities– Security Services– System Management Tools– Development and Test Tools– Applications

System-wide and local views– Product-specific


Importance of the Logical Architecture Consistency

– Must align to physical architecture assignment

Interoperability– Bounds (or, at least defines)

requirements for software compatibility Management

– Number of instances– Number of licenses– Number of users– Cost basis


Logical Architecture – a First Look – the Framework

Operating System

Network Managers

Data/DatabaseManagers

Applications

Compilers andInterpreters

Development andTest Tools

Service UtilitiesSystem Management

Tools

Security Services

Browsers


A Logical Architecture Exists at Every Node

Recalling the distributedtopology described in anearlier chart involving:•Baltimore•Pittsburgh•Fort Wayne•Kansas City•Denver•MissoulaIt is important to notethat the logicalarchitecture must exist ateach node

Operating System

Network Managers


Applications




Tools

Security Services

Browsers


Node Specific Logical Architecture Framework only constant Products likely to be different

– By brand– By version within brand

Reflect the character of the enterprise– Degree to which stovepipe environments exist

• Impact of M & A (mergers and acquisitions)• Divisional, departmental, and workgroup

independence

– Technology heritage– Experience base– Strategic partnerships and relationships– Management strategies


Logical Architecture – a Case to Consider NORNE, the large energy company

mentioned earlier, was formed as the result of a “merger of equals” involving six local energy companies. Each of the partner companies had its own logical architecture. The new NORNE used a “best of breed” approach to select the logical architecture for resulting environment given the presumption that the physical architecture was to be reused.


Logical Architecture – a Case to Consider

Baltimore Pittsburgh Fort Wayne Kansas City Denver Missoula

Physical Architecture

IBM S/390 SUN E450 Gateway Hewkett Packard

Sun E10000 Dell

Operating System

VM/CMS; MVS

Solaris V7.1 Windows NT 4.0

HP-UX Solaris V7.2 Windows 2000

Network Manager

SNA TCP/IP TCP/IP TCP/IP Ethernet TCP/IP

Browsers TSO; CICS; Tuxedo

Netscape Netscape Netscape Netscape Internet Explorer

Data/Database Manager

IMS; DB2 Informix; Sybase; DB2

Oracle Sybase DB2 SQL Server

Compilers / Interpreters

FORTRAN; COBOL; C

C; C++; Java C; C++; COBOL

C; Java C; COBOL; Java

C; C++

Service Utilities

Platinum; Tivoli

BMC, Sun BMC Tivoli; BMC BMC None

Security Services

None X.500 Active Directory

X.500 X.500 Active Directory

System Management Tools

Standard IBM

Unicenter None Unicenter; OPENVIEW

Tivoli None

Development and Test Tools

None Powerbuilder

Developer 2000Designer 2000

PoertbuilderERwin; BPwin

ERwin; BPwin;

None


Logical Architecture – Presenting the Case Clearly complex Some overlap but no

consistency– Each node different

Present each node independently

Summarize the net result


Logical Architecture Displayed

IBM S/390

VM/CMS; MVS

SNA

IMS; DB2

Applications

FORTRANCOBOL;

CNone

Platinum; Tivoli Standard IBM

None

TSO; CICS; Tuxedo

IBM S/390

SUN E450

Solaris V 7.1

TCP/IP

InformixSybase DB2

Applications

CC++Java

Powerbuilder

BMC; Sun Unicenter

X.500

Netscape

SUN E450

Windows NT 4.0

TCP/IP

Oracle

Applications

CC++

Cobol

Designer 2000Developer 2000

BMC Unicenter

Active Directory

Netscape

Gateway

Gateway

Hewlwtt-PackardHP-UX

TCP/IP

Sybase

Applications

CJava

PowerbuilderERwinBPwin

TivoliBMC

UnicenterOPENVIEW

X.500

Netscape

Hewlwtt-Packard

Solaris V 7.2

Ethernet

DB2

Applications

CCOBOL

Java

ERwinBPwin

BMC Tivoli

X.500

Netscape

SUN E10000

Windows 2000

TCP/IP

SQL Server

Applications

CC++

None

None None

Active Directory

Internet Explorer

Dell

Key: Model, page 30


Application Architecture


Application Architecture Reflects the decomposition of

applications into objects and components

Every application has an architecture Application architecture mirrors

decomposition of business processes and functionality– Functional rather than technical– Not product specific (generally speaking)

• Exception may be when a COTS* product is used to provide application functionality

* COTS Commercial Off The Shelf


Decomposition of Applications Applications comprised of a set

of subcomponents – Analogous to the systems of the

human body Subcomponents can be further

decomposed until objects and modules are identified– Organization structure model


Decomposition of Applications

Application

FunctionFunctionFunction

ReusableReusableObjectsObjects

TasksTasks

ProgramsPrograms


Application Architecture – Considerations Applications exist to support the

accomplishment of a business process– MUST logically mirror “how business gets done”– MUST improve accuracy and timeliness

• Applications have been funded to improve productivity

Programs most closely align with functional tasks– Not (necessarily) a 1::1 relationship

• Can be M::M– One task may require more than one program– One program may support achievement of several tasks

– Constructed from library of reusable objects• Logic to execute an atomic business process


Application Architecture - Considerations Computer programs must associate

product technology dependencies– COTS facilitation– Compilers/interpreters– Data managers– Library services

• Including repositories and/or data dictionary services

Computer programs must understand data architecture– Conceptual data model– Logical data model– Physical data model


Depicting the Applications Architecture

DBMSREUSABLE

OBJECT

LIBRARY

LIB

RA

RY

SER

VIC

ES

LOCAL LOGIC

DBMSREUSABLE

OBJECT

LIBRARY

LIB

RA

RY

SER

VIC

ES

LOCAL LOGIC

DBMSREUSABLE

OBJECT

LIBRARY

LIB

RA

RY

SER

VIC

ES

LOCAL LOGIC

DBMSREUSABLE

OBJECT

LIBRARY

LIB

RA

RY

SER

VIC

ES

LOCAL LOGIC

DBMSREUSABLE

OBJECT

LIBRARY

LIB

RA

RY

SER

VIC

ES

LOCAL LOGIC

DBMSREUSABLE

OBJECT

LIBRARY

LIB

RA

RY

SER

VIC

ES

LOCAL LOGIC

DBMSREUSABLE

OBJECT

LIBRARY

LIB

RA

RY

SER

VIC

ES

LOCAL LOGIC

DBMSREUSABLE

OBJECT

LIBRARY

LIB

RA

RY

SER

VIC

ES

LOCAL LOGIC

DBMSREUSABLE

OBJECT

LIBRARYLIB

RA

RY

SER

VIC

ES

LOCAL LOGIC

DBMSREUSABLE

OBJECT

LIBRARY

LIB

RA

RY

SER

VIC

ES

LOCAL LOGIC

DBMSREUSABLE

OBJECT

LIBRARY

LIB

RA

RY

SER

VIC

ES

LOCAL LOGIC

DBMSREUSABLE

OBJECT

LIBRARY

LIB

RA

RY

SER

VIC

ES

LOCAL LOGIC

TasksTasks

RedRed

WhiteWhite

BlueBlue

PrograProgramm


Depicting the Application Architecture – Level of Detail At the application level

– Must show all functions (subsystems) At the function (subsystem) level

– Must show all tasks– Tasks may occur in more than one

subsystem (e.g., Reporting) At the task level

– Must show all programs– Programs may be used to support more

than one task At the program level]

– Must show all engaged components


Presenting the Application Architecture Not depicting in context

detracts from value– Follow the “application structure

tree”– Use hyperlinks to call up details

DBMSREUSABLE

OBJECT

LIBRARY

LIB

RA

RY

SER

VIC

ES

LOCAL LOGIC

Hyperlink


Data Architecture


Data Architecture Representation of the enterprise in terms

of its data Primary concern – data as a managed asset

– Data only non-renewable information asset– Data only irreplaceable information asset

Secondary concern – data stores– Databases– Data Warehouses– Archives– Files

Not concerned with DBMS software and supporting utilities– Considered as part of Logical Architecture


Subject Data (or, Data Subjects) Robert Holland circa 1979 – 1980

– An enterprise can be represented by modeling its data

– An enterprise can be initially decomposed into data subjects

• Represent a major enterprise focus area• Decomposable

– Iterative until “atomic level” of data has been reached– Complexity of decomposition is a function of the

enterprise• Enterprise size• Enterprise diversity

– Data will “overlap” across data subjects• Basis for identifying relationships amongst data

Foundation for developing the conceptual data model


Data Models Conceptual data model

– Logical groupings of data (ENTITIES)– Relationships among entities– NO physical characteristics– Normalized (to at least BCNF*)

Logical data model– Ascribes physical characteristics to conceptual model

• Data type• Data size

– Identifies initial values and/or value ranges– De-normalized based on performance requirements

Physical data model– Describes the logical model in terms of the DBMS or

file management software to be used for implementation

*BCNF *BCNF Backus-Codd Normal Form Backus-Codd Normal Form


Data Distribution Data models describe relationships

– Independent of data usage Data usage organization or enterprise

dependent– Depends on business rules, processes, and

topology• Distributed organizations tend to distribute

processing• Data must be proximate to where it is processed

– Minimize network traffic– Optimize network capacity

– Data must be available• Accessible• Reliable• Current to established standards• Maintainable


Data Architecture Issues and Constraints Database must be recoverable in

the event of failure– Backing up of the database must be

practical Database must be available to

users during published hours Data must be available to meet

functional needs Data must be grouped to optimize

processing throughput


Organization of Data Categories

– Distribution• Distributing the contents of the database across several

system nodes– Replication

• Repeating the contents of all or part of the database across several system nodes

– Mirroring• Making an image copy of the database (or a part) at the

same node• Provides an online backup for the database when

continuous processing is required– Segmentation

• Organizing the database is sections so as to optimize processing

Tables, views, indexes, tablespaces, databases etc are domain of DBMS’s


Distributed DatabasesWith distributed databases, a different segment of the database is stored at each of several nodes.


Replicated DatabasesWith replicated databases, all or part of the database content exists at more than one systemnode. In this example, three parts of the database are replicated at two sites each and three are not replicated.

Database


Mirroring Image copy of all or part of the

database Located at the same node

– Differs from replication • Different node

Intended to provide real time continuity

Database

Mirror


Segmentation

Technique for grouping data in a way that logically supports processing requirements

Can be used in conjunction with– Distribution– Replication– Mirroring

Frequently application dependent


Other Aspects of Data Architecture Physical files

– File assignment• What data groupings exist within a given

physical file?

– File allocation• What physical files reside on which physical

storage devices?

– Compatibility or conflict• Contention for I/O services

Database sizing must be a factor


Data Architecture Impacts and Implications

Distributed

Database

Replicated

Database

MirroredDatabas

e

Segmented

Database

File Assign &Allocatio

n

Database

Sizing

DatabaseBackup

DatabaseRecovery

DatabaseReorg’tn

User Queries

User Updates

ArchitectureActivity

Explain how each architecture feature impacts the various

activities involving the database.

Explain how each architecture feature impacts the various

activities involving the database.


Interface Architecture


Interface Architecture Describes the interfaces among

architecture components– Abstraction– Encapsulation

Focus on software– Applications within the Application

Architecture– Access to COTS* software packages

Provides information to elevate understanding to the interface level– Details of interface participants less

relevant*Commercial Off the Shelf


Interface Architecture: Context Diagram View

ApplicationApplicationSystemSystem

Input

Input

Output

Output

Interfaces are sometimes described in terms ofInterfaces are sometimes described in terms of“goesinto” and “goesoutof” constructs“goesinto” and “goesoutof” constructs


Interface Architecture: Understanding the Components An interface exists whenever two

processing components communicate with each other– Example - Application program with database

management system via DML*

An interface involves sharing between two processing components– Data– Business rules and logic

An interface involves two and only two processing components– Many components may share a generalized ICD**

*Data Manipulation Language**Interface Context Definition


Interface Architecture: By way of Explanation

ApplicationApplication22

ApplicationApplication11

Data Store Data Store

Each interface isEach interface isunique based onunique based onthe particular the particular requirementsrequirements


Abstraction

The destination application has no need to know any more information than is contained in the interface– Subroutine parameter list– Module invocation– Query construct


Encapsulation The knowledge of the source application

is limited to the information published by the source application

NOT possible to know any more about the internal workings of the source application than the published interface

Encapsulation typical of – Operating systems– Database management systems– COTS application packages (e.g., SAP/R3)– System management tools


Interface Architecture: An Example NORNE (the large energy

conglomerate described earlier) has selected SAP/R3 as its ERM* tool. As an ERM tool, SAP/R3 provides a payroll processing module (SAP/PR). However, the SAP/R3 designers have decided that the responsibility for preparing pay check advisories and initiating direct deposit processing is the responsibility of the client

*ERM – Enterprise Resource Management


Interface Architecture: An Example SAP/R3 is a closely coupled COTS application

product– Fully encapsulated– Published interfaces

• ABAP• BAPI

NORNE has legacy program(s)– Prepare pay check advisories– Initiate direct deposit processing

ACH has published interfaces– Automated Clearing House– Manages funds transfer from payer account to

payee account

Programming languages that describe the interface(s) and transformations


Interface Architecture: An Example

NORNENORNEPaycheckPaycheckProgramProgram

SAP/PRSAP/PR

ACHACH

Published interfacefrom SAP

ABAP or BAPIABAP or BAPI

Published interfacefrom NORNE

ABAP or BAPIcode executes thelogic required topass data betweenthe programs

Even

t trig

ger; d

ata;

Even

t trig

ger; d

ata;

ackn

owle

dgemen

t

ackn

owle

dgemen

t

Published interfacefrom ACH

Published interfacefrom NORNE

Message-based Interface

BanksBanks Published interfacefrom ACH

Event trigger;

data

Event trigger;

dataMessage-based Interface


Interface Architecture: Capturing the Rules

Target ApplicationsTarget ApplicationsS

ou

rce

Ap

plicati

on

s

Interface Rules Go HereInterface Rules Go Here


Integration Architecture


Integration Architecture High-level framework that shows

relationship of component architectures– Network– Physical– Logical– Application– Data– Interface

Initial profile subject to “drill down”


Integration Architecture: Topology

Start by showing the topologyStart by showing the topologyand connectivity of the environmentand connectivity of the environment


Integration Architecture: Network Components

Mainframe Router

LocalServers

Router Local Servers

With Clients

Show how the network Show how the network architecture maps to the architecture maps to the topologytopology


Integration Architecture: Physical Components

Clients

Web Server

ApplicationServers

Data Server

Establish a hyperlink Establish a hyperlink from each location in from each location in the topology that the topology that provides a detailed provides a detailed configuration of what configuration of what physical components physical components are at that specific are at that specific locationlocation


Integration Architecture: Logical Components

Clients

Web Server

ApplicationServers

Data Server


Operating System

Network Managers


Applications




Tools

Security Services

Browsers

Establish a hyperlink Establish a hyperlink from each physical from each physical architecture architecture component to the component to the logical architecture logical architecture on that componenton that component


Integration Architecture: Application Components

Clients

Web Server

ApplicationServers

Data Server


Operating System

Network Managers


Applications




Tools

Security Services

Browsers

Establish a Establish a hyperlink from hyperlink from each physical each physical architecture architecture component to the component to the logical logical architecture on architecture on that componentthat component

Application



TasksTasks

ProgramsPrograms

Establish a hyperlinkEstablish a hyperlinkto the applicationto the applicationdecomposition at adecomposition at aparticular locationparticular location


Integration Architecture: Data Components

Clients

Web Server

ApplicationServers

Data Server


Operating System

Network Managers


Applications




Tools

Security Services

Browsers

Establish a Establish a hyperlink from hyperlink from each physical each physical architecture architecture component to the component to the logical logical architecture on architecture on that componentthat component

Establish a hyperlinkEstablish a hyperlinkto the applicationto the applicationdecomposition at adecomposition at aparticular locationparticular location

Application



TasksTasks

ProgramsPrograms

ReplicatedReplicatedMirroredMirrored

DistributedDistributed

Establish a hyperlink

Establish a hyperlink

to the data component

to the data component

on each physical

on each physical

architecture component

architecture component


Integration Architecture: Interface Components Interface rules

– Associated with each object• Independent• Reusable

Application



TasksTasks

ProgramsPrograms

•For each component inFor each component in the application architecture, the application architecture, create a hyperlink that statescreate a hyperlink that states the public interface rules the public interface rules

DBMSREUSABLE

OBJECT

LIBRARY

LIB

RA

RY

SER

VIC

ES

LOCAL LOGIC


Types of Architectures Physical – reflects the hardware elements Logical – reflects the software elements Network – reflects the communications

topology elements Application – reflects the decomposition of

each application into objects and components Data – models the enterprise based upon its

data subjects Interface – describes how key architectural

components interact or interoperate with each other

Integration – reflects the combination of physical, logical, network, and applications into one common view

Together, they tell the story of an enterprise’s IT environmentTogether, they tell the story of an enterprise’s IT environment

System and Software Architectures Ed Green

Documents

Transcript of System and Software Architectures Ed Green