The CUBiT plugin makes setting up and managing SSH tunnels faster and easier than having to do it manually.
When you add a tunnel in the CollabNet Sites view, you specify the host and port numbers in a dialog box. This information get saved for future sessions. After this, whenever you log into your Cubit node, the tunnel is automatically reconnected. Moreover, when there are multiple CUBiT nodes that you work on, you can store the tunnel settings for all of them, and keep them ready for future use.
When your CUBiT setup is deployed for "direct-access", you can directly access your Client Node from your corporate network using your laptop or desktop, without going through the CUBiT Manager. You do not need an SSH tunnel to access your host, though it is possible.
When your CUBiT setup is deployed for "isolated-access", each Client Node is on a Network Address Translation (NAT) network behind its CUBiT Manager. Here you need to tunnel through the CUBiT Manager to access your Client Node.