IT Infrastructure Architecture model

The definition of infrastructure as I defined it in my book is based on the IT systems model as shown below. In this model an IT system is defined as processes that use information, where this information is stored and managed using applications. Applications need application integration to work together and they need infrastructure to run on. All of this is managed by systems management.

An IT system, however, does not only provide functionality to users; functionality is supported by non-functional attributes as well. These non-functional attributes are affected by the configuration of each and every one of the IT system’s components, as shown in the next figure. Although many other non-functional attributes are defined, it is my experience that availability, performance and security are almost always the essential ones in IT infrastructure architectures.

When we zoom in on the applications layer, we can define three types of building blocks, as shown in the next figure. Please note that while the building blocks in this figure are presented as  stacked layers, there is no hierarchy in these layers. Client applications are not based on office applications or the other way around. The same goes for the more detailed figures later in this article; including the infrastructure layers.

  • Client applications typically run on end user devices (PC’s, laptops, etc.). Typical client applications are web browsers, word processors, and mail clients.
  • Office applications provide applications most organizations use. Examples are mail servers, portals, collaboration tools, and instant messaging. Most organizations run these office applications more or less out of the box.
  • Business specific applications are applications that are typically highly customized or even custom built. Some examples are Customer Relationship Management (CRM), Enterprise Resource Planning (ERP), Supervisory Control And Data Acquisition (SCADA) systems, and applications that are created for a specific business process (like a call center system).

Most applications need some additional services to enable them to work together. In the next figure these services are shown.

  • Front-end servers are typically web servers (like Apache HTTP Server and Microsoft Internet Information Services – IIS) that provide end users with interactions to applications by presenting application screens in web browsers.
  • Application servers act as containers running the actual application. Examples are Java or .Net application servers and frameworks (like IBM WebSphere, Apache Tomcat, Windows.Net and Oracle Application Server – OAS).
  • Connectivity entails FTP servers, Extraction, Transformation and Load (ETL) servers, and Enterprise Service Buses – ESBs like Microsoft BizTalk, TIBCO ActiveMatrix Service Bus, IBM MQ, and SAP NetWeaver PI.
  • Databases – or database management systems (DBMSs) – provide a way to store and retrieve structured data. Examples are Oracle RDBMSIBM DB2, Microsoft SQL Server and MySQL.

A multi-tier application uses these application services to host components of an application independently of each other (see the figure below).

The next figure visualizes and categorizes the infrastructure building blocks and their non-functional attributes.

The model shows the building blocks that together form the IT infrastructure. These building blocks are:

  • End User Devices are the devices used by end users to work with applications, like PCs, laptops, thin clients, mobile devices, and printers.
  • Operating systems are collections of programs that manage a computer’s internal workings: its memory, processors, devices, and file system.
  • Virtualization acts as an abstraction layer between the operating system and the server hardware. Virtualization enables a single physical machine to run multiple operating systems on virtual machines.
  • Storage – The storage building block contains hard disks, tapes, Direct Attached Storage (DAS), Network Attached Storage (NAS), and Storage Area Networks (SANs).
  • Networking is a very important building block of any infrastructure, connecting all components. It includes routers, switches, firewalls, WAN (wide area network), LAN, dial-in, Internet access, and VPNs (Virtual Private Network), and (on the network application level) relatively simple services like DNSDHCP, and time services, necessary for the infrastructure to work.
  • Servers are the main physical processing units; computers located in the datacenter.
  • Datacenters – Typically IT hardware is located in a datacenter. Datacenters provide (uninterruptible) power supply, cooling, computer racks, and physical security measures.

Please note that – as stated before – these building blocks are not per definition hierarchically related. Servers need both networking and storage, and both are equally important.

In the next figure the building blocks needed for systems management tasks are shown.

  • Monitoring continuously inspects all relevant IT components for events like  error conditions or signs for (upcoming) failures (like a disk with only little free space left). Monitoring can lead to the generation of alarms to systems managers, who can take action to fix the event leading to the alarm.
  • Infrastructure management systems are used to centrally manage the IT components, like starting and stopping applications, performing patching, handling back-ups,  and remotely logging in to fix problems.
  • Infrastructure services provide additional services to the application landscape, like authentication and authorization (with Active Directory or LDAP), system logging, job scheduling, and batch processing.
  • Process management entails the human processes needed to perform systems management. ITIL and COBIT are the two best known frameworks for systems management processes.

This entry was posted on Vrijdag 16 November 2012

Earlier articles

Infrastructure as code

My Book

DevOps for infrastructure

Infrastructure as a Service (IaaS)

(Hyper) Converged Infrastructure

Object storage

Software Defined Networking (SDN) and Network Function Virtualization (NFV)

Software Defined Storage (SDS)

What's the point of using Docker containers?

Identity and Access Management

Using user profiles to determine infrastructure load

Public wireless networks

Supercomputer architecture

Desktop virtualization

Stakeholder management

x86 platform architecture

Midrange systems architecture

Mainframe Architecture

Software Defined Data Center - SDDC

The Virtualization Model

What are concurrent users?

Performance and availability monitoring in levels

UX/UI has no business rules

Technical debt: a time related issue

Solution shaping workshops

Architecture life cycle

Project managers and architects

Using ArchiMate for describing infrastructures

Kruchten’s 4+1 views for solution architecture

The SEI stack of solution architecture frameworks

TOGAF and infrastructure architecture

The Zachman framework

An introduction to architecture frameworks

How to handle a Distributed Denial of Service (DDoS) attack

Architecture Principles

Views and viewpoints explained

Stakeholders and their concerns

Skills of a solution architect architect

Solution architects versus enterprise architects

Definition of IT Architecture

What is Big Data?

How to make your IT "Greener"

What is Cloud computing and IaaS?

Purchasing of IT infrastructure technologies and services

IDS/IPS systems

IP Protocol (IPv4) classes and subnets

Introduction to Bring Your Own Device (BYOD)

IT Infrastructure Architecture model

Fire prevention in the datacenter

Where to build your datacenter

Availability - Fall-back, hot site, warm site

Reliabilty of infrastructure components

Human factors in availability of systems

Business Continuity Management (BCM) and Disaster Recovery Plan (DRP)

Performance - Design for use

Performance concepts - Load balancing

Performance concepts - Scaling

Performance concept - Caching

Perceived performance

Ethical hacking

Computer crime

Introduction to Cryptography

Introduction to Risk management

The history of UNIX and Linux

The history of Microsoft Windows

Engelse woorden in het Nederlands

Infosecurity beurs 2010

The history of Storage

The history of Networking

The first computers

Cloud: waar staat mijn data?

Tips voor het behalen van uw ITAC / Open CA certificaat

Ervaringen met het bestuderen van TOGAF

De beveiliging van uw data in de cloud

Proof of concept

Een consistente back-up? Nergens voor nodig.

Measuring Enterprise Architecture Maturity

The Long Tail

Open group ITAC /Open CA Certification

Human factors in security

Google outage

SAS 70

De Mythe van de Man-Maand

TOGAF 9 - wat is veranderd?

DYA: Ontwikkelen Zonder architectuur

Landelijk Architectuur Congres LAC 2008

InfoSecurity beurs 2008

Spam is big business

Waarom IT projecten mislukken

Stroom en koeling

Laat beheerders meedraaien in projecten

De zeven eigenschappen van effectief leiderschap


Een ontmoeting met John Zachman

Open CA (voorheen: ITAC) - IT Architect certification

Persoonlijk Informatie Eigendom


Live computable webcast

Lezing Trends in IT Security

Hardeningscontrole en hacktesting


Information Lifecycle Management - Wat is ILM

LEAP: de trip naar Redmond

LEAP: De laatste Nederlandse masterclasses

Scada systemen

LEAP - Halverwege de Nederlandse masterclasses

Beveiliging van data - Het kasteel en de tank

Waarom je geen ICT architect moet worden

Non-functional requirements

Redenen om te backuppen

Log analyse - gebruik logging informatie

LEAP - Microsoft Lead Enterprise Architect Program

Archivering data - more than backup

Patterns in IT architectuur

Tot de dood ons scheidt

High Availability clusters

Hoe geef ik een goede presentatie

Lagen in ICT Beveiliging

Zachman architectuur model

High performance clusters en grids

Redenen om te kiezen voor Open Source software

Monitoring door systeembeheerders

Wat is VMS?

IT Architectuur certificeringen

Storage Area Network's (SAN's)

Systeembeheer documentatie

Wat zijn Rootkits

Virtualisatie van operating systems

Kenmerken van Open Source software

Linux certificering: RHCE en LPI

99,999% beschikbaarheid

Het infrastructuur model

Sjaak Laan

Recommended links

Genootschap voor Informatie Architecten
Ruth Malan
Informatiekundig bekeken
Gaudi site
XR Magazine
Esther Barthel's site on virtualization


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