Getting a Networking Job: Computing Architecture and Design - dummies

Getting a Networking Job: Computing Architecture and Design

By Peter H. Gregory, Bill Hughes

Every successful networking professional is familiar with the basics of computing architecture and design: how computers are architected internally, and the ways they are used, including virtualization and cloud computing.

Basic concepts in computing architecture and design

Networking professionals must understand how computers are designed and how they function. This applies to computers used — on-site and computers that are a part of cloud-based services.

Computer hardware architecture

Networking professionals need to understand how computer hardware functions, so that they can ensure that the hardware is properly managed and used. Modern computers are made up of the following components:

  • Central processing unit (CPU): The component where computer instructions are executed and calculations performed.

  • Main storage: The component where information is stored temporarily. Often known as RAM, main storage is usually volatile and its contents lost if power is removed or the computer turned off.

  • Secondary storage: The component where information is stored permanently. Information stored here is persistent even when the computer is switched off. Secondary storage is often organized into one or more file systems, which are schemes for the storage and retrieval of individual files.

  • Bus: The component where data and instructions flow internally among the CPU, main storage, secondary storage, and externally through peripheral devices and communications adaptors. Popular bus architectures include SCSI SATA, IEEE1394, and USB.

  • Firmware: Software stored in persistent memory, generally used to store initial instructions that are executed when the computer is switched on.

  • Communications: Most computers include one or more communication components — otherwise, how would you get problems into it and results out of it?

  • Security hardware: Components for various security functions, such as a Trusted Platform Module (TPM), which is used to store and generate cryptographic keys, smart card readers, and fingerprint scanners.

Computer operating system

A computer operating system (OS) consists of the set of programs that facilitate the operation of application programs and tools on computer hardware. The components of an OS include the kernel, device drivers, and tools.

The main functions performed by an operating system are

  • Process management: Processes are the individual programs that run on a computer. The OS starts and stops processes and makes sure they do not interfere with each other.

  • Resource management: The OS allocates and manages the use of main storage, secondary storage, communications, and attached devices.

  • Access management: The OS manages authentication as well as access to resources such as files and directories in secondary storage.

  • Event management: The OS responds to events such as the insertion or removal of media and devices, keystrokes, or mouse movements.

  • Communications management: The OS manages communications to ensure that incoming and outgoing communications are handled and routed properly.

An operating system can run directly on computer hardware or through a scheme called virtualization, in which many separate copies of operating systems can run simultaneously on a computer. In virtualization, the main controlling program is called the hypervisor, and each running OS is called a guest. The hypervisor’s jobs are to allocate computer hardware resources to each guest and to prevent guests from interfering with each other.

Virtualization permits an organization to make better use of its resources. Instead of running one operating system per server, multiple operating systems can run on each server, making better use of hardware investment and rack space.

With commercial virtualization tools, OS instances can be moved from one hardware platform to another, and OS instances can be easily cloned to enable more running copies of a server if demand requires it.

Cloud services

The adoption of cloud services is in full swing despite the fact that many still don’t understand how cloud services work. An organization using cloud computing has chosen to use computing or application resources that are owned by another organization and located away from the organization’s premises.

The three common types of cloud services follow:

  • Infrastructure as a Service (IAAS): Service providers enable customers to lease virtual machines, servers, storage, network functions, and so on. Examples include Amazon Web Services, Microsoft Azure, and Google Compute Engine (GCE).

  • Software as a Service (SAAS): Service providers enable customers to use software applications managed by cloud service providers. Examples include Salesforce, Office365, and Cisco WebEx.

  • Platform as a Service (PAAS): Service providers run application software with application programming interfaces (APIs) to which customers can connect their application. Examples include Engine Yard, Google App Engine, and Microsoft Azure Web Sites.

An organization can utilize cloud services in the following ways:

  • Public cloud: An organization utilizes cloud services that are operated by and located at a cloud service provider’s data center.

  • Private cloud: An organization builds its own cloud computing infrastructure using hardware assets that it owns, and locates it in its own data center. An organization that builds a private cloud wants the logical capabilities of cloud computing but also wants to retain ownership and control of the hardware supporting it.

  • Hybrid cloud: An organization utilizes a combination of public cloud services with its in-house resources generally wants control of specific information or hardware assets.

  • Dedicated public cloud: An organization utilizes public cloud services on hardware dedicated to that organization. An organization that uses dedicated public cloud wants the flexibility of cloud services but is unwilling to share infrastructure with other tenants.

Emerging issues in computing architecture and design

Issues that tend to keep networking professionals on their toes include:

  • Internet of Things (IoT): Networking professionals worry that insufficient work is put into developing sound security models and designs to prevent attacks in new Internet-connected products.

  • Speed to market: Many organizations, in attempts to get newly developed products to market more quickly, skip security designs, reviews, and controls, thereby leaving products open to attack.

  • Flawed access control: Many organizations lack the skills to implement sound, effective access controls in their systems, resulting in unnecessary exposure of sensitive data.