H

H.225

A protocol that performs call setup and RAS (Registration, Admission, and Status) functions.

H.245

A protocol that performs call control, including exchanging gateway capabilities (for example, the supported CODECs) between H.323 end systems.

H.323

A suite of protocols that supports audio, video, and data collaboration.

Hot Standby Router Protocol (HSRP)

A Cisco-proprietary protocol that allows one router to back up another router.