3.0 Network+ Certification Cram Notes : Network Operations

3.3 High availability and disaster recovery concepts

On the other hand, a warm site is a disaster recovery solution that has all the necessary hardware and software in place, but it may not be fully configured or tested. In the event of a disaster, the organization can start operations quickly because the infrastructure is already in place. However, the organization may need to make some additional preparations or configurations to get everything up and running.

Active-active vs. active-passive refers to different types of configurations used in high availability (HA) systems. In an active-active configuration, both redundant components (e.g., servers, switches, routers) are active and processing traffic simultaneously. In the event of a failure, traffic is redirected to the remaining active component. In contrast, an active-passive configuration involves one component being designated as the primary device, while the other is kept in a standby mode. In the event of a failure, the standby device takes over processing traffic.

Multiple Internet Service Providers (ISPs) refers to the use of more than one ISP to provide connectivity to an organization. This increases the redundancy and resilience of the network as traffic can be automatically redirected in the event of a failure of one of the ISPs.

Virtual Router Redundancy Protocol (VRRP) and First Hop Redundancy Protocol (FHRP) are protocols used to implement redundancy in routing protocols. They provide a mechanism for automatically redirecting traffic in the event of a failure of the primary routing device. The key difference between VRRP and FHRP is that VRRP provides redundancy at the IP layer, while FHRP provides redundancy at the data link layer.

The terms MTTR, MTBF, RTO, and RPO are related to the availability and reliability of a system.

1. Mean time to repair (MTTR) - refers to the average amount of time it takes to repair a failed component of a system. This time includes the time to identify the problem, obtain replacement parts, perform the repair, and perform any necessary tests to ensure the system is functioning correctly.

2. Mean time between failure (MTBF) - is the average time that a system operates without failure. This metric is used to determine the reliability of a system, and is calculated by dividing the total operating time by the number of failures.

3. Recovery time objective (RTO) - is the maximum amount of time that a system is allowed to be unavailable in the event of a failure. The RTO is the maximum amount of time that a business can tolerate the system being down and is used to determine the necessary level of redundancy and disaster recovery planning.

4. Recovery point objective (RPO) - refers to the maximum acceptable amount of data loss in the event of a failure. The RPO is used to determine the necessary frequency of backups, and to determine the level of data protection that must be in place.

Network device

Backing up the state of a network device refers to creating a snapshot of its current operating state, which includes information about its configuration, system logs, performance statistics, and other related data. This data can be used to restore the network device to a previous state in the event of a failure, or to migrate the device to another location or network.

The configuration of a network device is the set of parameters and settings that determine its behavior and functionality. This includes the IP addresses of the device, the routing protocols it is using, the access control lists (ACLs) that define its security posture, and other similar data. Backing up the configuration of a network device can be critical for ensuring network availability, as it allows administrators to quickly restore the device to a known, working state in the event of a failure or other issue.

In summary, backing up the state and configuration of a network device is a critical aspect of maintaining network availability, as it helps to ensure that the device can be quickly and easily restored in the event of a failure.