Five Nines mean that systems and services are available 99.999% of the time.
also means both planned and unplanned downtime is less than 5.26 minutes per year

Healthcare facilities require high availability to provide around-the-clock care for patients

The Public Safety industry includes agencies that provide security and services to a community, state, or nation

The Finance Industry needs to maintain high availability for continuous trading, compliance, and customer trust

the Retail Industry depends on efficient supply chains and the delivery of products to customers.
Disruption can be devastating, especially during peak demand times such as holidays

There are many different types of threats to high availability, the threats can range from failure of a mission-critical application to severe storm such as a hurricane or tornado.

Threats can also include catastrophic event such
as a terrorist attack, building bombing, or building fires.

an Org. needs to know what hardware and software assets they have in order to protect them.

Assigns all resources of an org into a group based on common characteristics.

An Org should apply an asset classification system to documents, data records, data files, and disks

As part of an IT asset management system, an Org specifies the acceptable IT assets that meet its objectives

is the process of analyzing the dangers posed by natural and human-caused events to the assets of an org.

involves reducing the severity of the loss or the likelihood of the loss from occurring.

Many technical controls mitigate risk including authentication systems, file permissions, and firewalls

Defense in dept will not provide an impenetrable cyber shield, but it will help an org minimize risk by keeping it one step ahead of cyber criminals.

the Media Industry, the news cycle is now around the clock 24/7/365

Adopt a uniform way of identifying info to enure uniform protection

Quantify the probability and impact of the identified threats

Balance the impact of the threat against the cost of the countermeasure

Reduce the risk by designing a new business process with adequate built-in risk control and containment measures from the start

Avoid risk altogether would include measures such as physically disconnecting from the internet

Accept the Risk and Periodically re-assess accepted risks in ongoing processes as a normal feature of business operations and modify mitigation measures.

Transfer risks to an external agency (A service level agreement or insurance company)

Provides the most comprehensive protection.

If cybercrims. penetrate one layer, they still have to contend with several more layers with each layer being more complicated than the previous

Layering is creating a barrier of multiple defenses that coordinate together to prevent attacks

Access to data and info reduces the possibility of a threat.
An organization should implement the principle of least privilege

refers to changing the controls and procedures at different layers.

Breaching one layer does not compromise the whole system

An organization may use different encryption algorithms or authentication systems to protect data in different states

An org should not reveal any info that cyber-crims can use to figure out what version of the OS a server is running or the type of equipment it uses

complexity does not necessarily guarantee security.
if the process or technology are too complex, misconfigs or failure to comply can result.

Can be a specific piece of hardware, a process, a specific piece of data or even an essential untility

single points of failure are the weak links in the chain that can cause disruption of the Org's operations

Generally, the solution to a single point of failure is to modify the critical operation so that it does not rely on a single element

The Org can also build redundant components into the critical operations to take over the process should one of these points fail

Ensures system availability in the even of a component failure

ex. a car has four tires (N) and a spare tire in the trunk in case of a flat (+1)

RAID combines multiple physical hard drives into a single logical unit to provide data redundancy and improve performance

RAID takes data that is normally stored on a single disk and spreads it out among several drives. If any single disk is lost, the user can recover data from the other disks where the data also resides

Using multiple drives makes retrieving requested data faster, instead of relying on just one disk to do the work

A RAID solution can be either hardware-based or software-based.

STP ensures that redundant physical links are loop-free.
It ensures that there is only one logical path between all destinations on the network

STP intentionally blocks redundant paths that could cause a loop

The basic function of STP is to prevent loops on a network when switches interconnect via multiple paths

The default gateway is typically the router that provides devices access to the rest of the network or to the Internet.
If there is only one router serving as the default gateway, it is a single point of failure.

Involves the ability of a network to dynamically recover from the failure of a router acting as a default gateway known as first-hop redundancy

HSRP provides high network availability by providing first-hop routing redundancy

Runs the VRRP protocol in conjunction with one or more other routers attached to a LAN.

In a VRRP configuration, the elected router is the virtual router master, and the other routers act as backups, in case the virtual router master fails

GLBP protects data traffic from a failed router or circuit, like HSRP and VRRP, while also allowing load balancing (Also called load sharing) between a group of redundant routers

An Org may need to consider location redundancy depending on its needs.

Syncs both locations in real time

Not synchronized in real time but close to it

Updates the backup data location periodically

Resiliency defines the methods and configurations used to make a system or network tolerant of failure.
Routing protocols provide resiliency.

Most bandwidth conservative option because it does not require a constant connection

Resilient design is more than just adding redundancy. Resiliency is critical to understand the business needs of the organization, and then incorporate redundancy to create a resilient network.

The application's ability to react to problems in one of its components while still functioning

Many Orgs balance out the cost of resiliency of application infrastructure with the cost of losing customers or business due to application failure

A system designed by building multiples of all critical components into the same computer

Copying files for the purpose of being able to restore them if data loss occurs

Maintains a secure working copy of the router IOS image file and a copy of the running config file