What is the function of line vty in router configuration?

Vty Line Authentication and Authorization

The system supports 20 virtual tty (vty) lines for Telnet, Secure Shell Server (SSH) and FTP services. Each Telnet, SSH, or FTP session requires one vty line. You can add security to your system by

VLAN Configuration

VLAN Configuration

This section discusses the guidelines for configuring VLANs on the Catalyst switch. You will learn the steps to configure VLANs, how to enable VTP domains, how to define a trunk, how to create a VLAN, and how to verify proper VLAN