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IT Essentials — Assessing Infrastructure and Networks

Hybrid

Hybrid network architecture, as the name would imply, is a combination of peer-to-peer (P2P) and
client-server types. Except for the smallest of networks, there is rarely a pure P2P or client-server
network, and functionally, all networks offer hybrid service models, depending on needed services. A
single node can use services from a server on the network while participating with a peer in a
distributed file system also on the network and serving information to a client, all on the same
network.

Functionally, network architecture is more than a system of connections among nodes. Modern
computing demands have advanced rapidly, and networks require the centralized control of a
client-service architecture for some demands, but also need the flexibility of open P2P relationships
for other demands.

Cloud-Based

Although external providers use these terms to market and explain their services and approaches, an
organization’s IT department may also use the terms if they offer such services.

The term “cloud” describes how data and information is stored and accessed over the internet, but
simplistically, it is the use of someone else’s computer network. The use of the term cloud is a
recognition that network architecture is largely irrelevant to most consumers of IT services, from
organizational IT systems to individual users. The Typical Cloud Architecture by Type and
Responsibility model (shown in greater detail on the next screen) depicts the on-premise and cloud
models and the typical corresponding responsibilities. However, some of these responsibilities may
vary on a case-by-case basis, and the organization is usually responsible for user provisioning,
access, and authentication.

Organizations are typically responsible for security IN the cloud, while the cloud provider is
responsible for security OF the cloud.

There are three general cloud service types in which the service type may be referred to as “’X’ as a
service,” abbreviated XaaS. XaaS means "delivery or anything as a service: products, services, and
technologies." The three general cloud service types include Infrastructure (IaaS), Platform (PaaS),
or Software (SaaS). Details on each of these cloud service models, compared with the traditional on-
premise model include:

On-premise — the organization is responsible for all aspects of the network, including maintaining
all servers, storage, OSs, and developing and maintaining applications.

Infrastructure as a Service (IaaS) — the organization owns the maintenance of servers within the
cloud. This is a pay-as-you-go model for network, servers, storage, applications, etc., where the size
can be modified on an as-needed basis. The recipient organization is responsible for all logical
configurations and maintenance, though they typically do not have access to the hardware.
Organizations that desire their own features and functionalities often use IaaS to develop

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