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Revised Infrastructure Model

In one of the first posts on this website I presented an Infrastructure Model. For the book I am writing, this infrastructure model is used as a basis for describing infrastructures. Because the original infrastructure model was created back four years ago i felt is was time for an upgrade on the model. This article (as part of my book) describes the revised infrastructure model.

No generally accepted definition of IT infrastructure exists and many people have different ideas about what IT infrastructures consists of. For developers, infrastructure is the platform to run their applications on. For network managers, infrastructure is the collection of all network equipment. For systems administrators, infrastructure is all equipment they manage and for the architect it is the basic layer to build the business services on. Because everyone has a different idea on what infrastructure is, we introduce the following definition of IT infrastructure:

IT infrastructure is the total set of foundation components that enables applications to function

The following model can be used to visualize the various components.

(click to enlarge)

This model shows the components from which an infrastructure is built (the horizontal planes). This stack of components is the basis on which applications can run. Part of the infrastructure is located in the data center, another part is located at the work place.

Vertically, three infrastructure specific non-functional attributes are shown. These attributes are valid for every component in the infrastructure. The non-functional attributes are security, availability and performance. Although many other non-functional attributes can be defined, these three are almost always very important in infrastructure architectures.

All parts of the infrastructure are maintained by performing systems management.

Infrastructure components in the data center 

Facilities

The basis of all IT is hardware that is located in a data center facilities. The facilities layer includes electricity and cooling, raised floors, fire detection and prevention, physical security, backbone cabling, etc.

Racks and enclosures

Located in the facilities are server racks. These racks contain the IT equipment. Blade based equipment is located in enclosures that are placed in the racks. This layer encompasses cabling, patching, labeling, (redundant) power supplies, etc.

Servers

Servers are the main components in any data center. They include CPUs, memory, local storage, BIOS, expansion slots and ports, etc.

Networking

The network is a very important part of any infrastructure. Dependent on the environment the network can be very complex. It contains routers, switches, NAT, Firewalls, WAN, LAN, dial-in, Internet access, VPN's, etc.

Storage

Most servers have internal storage, but usually storage these days is external. The storage component contains DAS, NAS, SAN, FC-AL, iSCSI, etc. Also backup and recovery solutions, and ILM and ECM are part of storage.

Virtualization

On the hardware the operating systems can be installed, but nowadays most hardware is virtualized first. The virtualization layer can be on machine level (creating virtual machines on which operating systems are installed), workstation virtualization (like VDI or terminal server solutions), storage virtualization (like disk arrays and virtual LUNs) and network virtualization (like virtual LANs - VLANs).

Operating Systems

Virtual servers run operating systems (OS's). The most popular operating systems are Microsoft Windows, Linux, UNIX and Apple OSX. However, there are a large amount of other operating systems, usually meant for special purposes, like real-time operating systems, or operating systems for embedded systems. Part of this layer is the way the OS's are deployed, tuning OS parameters, as well as management of users, groups, rights and drivers.

Infrastructure services

The infrastructure services layer consists of services like DNS, DHCP, Directory services, mail agents, etc.

Workstations

Workstations are the devices used by end users to work with applications. Workstations include PCs, laptops and mobile devices.

Peripherals

Any hardware device remotely attached to a computer (either a workstation or a server) is called a peripheral. Typical peripherals are printers, models, scanners, fingerprint readers or CAM machines.

Non-functional attributes (verticals)

Security

IT Security spans all components. IT security is a very large knowledge area. For infrastructure, it concerns mostly about technical solutions, like VPN, IDS, Access Control, Biometrics, Encryption, etc. Procedural security is mostly used in system administration. It spans creating users, access rights, and security demands for new hardware and software.

Availability

Availability contains areas like backup and restore, Disaster recovery, Failover, high availability clustering, Load balancing and replication.

Performance

The performance of an IT infrastructure is almost always very important and consists of areas like scalability, virtualization and high performance clusters.

System Administration

An important aspect is the administration of the environment. This includes procedures for taking systems and applications in production, maintaining systems and troubleshooting. Usually ITIL is used as a methodology for system administration.

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