Instructions for downloading the Cisco application to allow you to connect to the Notre Dame VPN can be found here:

http://secure.nd.edu/stay-secure/vpn.shtml

Why Might I Need to Use the VPN?

The VPN gateway is a network access service which permits remote systems to access the ND network as if they were physically located on the ND campus network.  In technical terms, it allows remote systems to obtain a campus IP address, for purposes of access to certain restricted on-campus systems.