Hot Rollover: A feature in network devices that allows changes to be made to the device's configuration without disrupting network traffic. It ensures continuous operation during updates or maintenance, common in devices like Cisco routers and switches.

Hot Site: A location that is equipped with the necessary hardware and software to quickly resume IT operations in the event of a disaster. It is used as a backup site for business continuity and disaster recovery. Examples include having a hot site set up in a different city or region, having duplicate servers and equipment on site, and regularly testing the hot site to ensure it is ready for use.

Hot swapping: Hot swapping is a method that allows the replacement or addition of computer system components without requiring a shutdown or reboot. This capability is crucial for essential systems that require high availability and minimal downtime. Hot swapping enables maintenance and upgrades, such as installing new storage drives or network cards while the system remains operational.

Hub: A network device that connects multiple computers or other network segments. In a hub-based network, the hub receives data packets and broadcasts them to all connected devices, regardless of the intended recipient. Hubs operate on the Physical Layer of the OSI model and have been largely replaced by smarter, more secure switches.

Hybrid cloud: A computing environment that combines a mix of on-premises, private cloud, and third-party, public cloud services with orchestration among these platforms. This allows organizations to benefit from the scalability and cost-effectiveness of public cloud computing while maintaining control over critical applications and sensitive data, providing a balanced approach to managing security and operational needs.

Hybrid cryptography: An approach to secure communication that combines the strengths of both symmetric and asymmetric encryption methods. The data is encrypted using a symmetric key for speed and efficiency, while the symmetric key itself is then encrypted with an asymmetric key for secure transmission. This blend of techniques allows large volumes of data to be transmitted securely and efficiently.