Like Telnet, SSH is a protocol for logging in to a remote host and executing commands on the remote host. Unlike Telnet, SSH uses special algorithms to encrypt the data stream, to ensure data stream integrity, and even to perform authentication in a safe and secure way. SSH is a secure, encrypted replacement for Telnet.
SSH provides remote command line interface (CLI) administration over an authenticated, encrypted connection. In a Network Protocol Manager deployment, Network Protocol Manager for EIGRP and Network Protocol Manager for IS-IS use SSH CLI to query EIGRP- and IS-IS-enabled Cisco devices for topology and status information.