Like Telnet, SSH is a network 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. Both SSH and Telnet provide access to a command line interface (CLI) on a remote host.
In an MPLS Manager deployment, the MPLS Topology Server uses SSH CLI or Telnet CLI for two purposes:
To query MPLS-enabled devices for topology information.
To execute on-demand LSP ping requests.