SSH is known for its secure shell protocol, from wikipedia.org its explain that :

Secure Shell or SSH is a network protocol that allows data to be exchanged over a secure channel between two computers. Encryption provides confidentiality and integrity of data. SSH uses public-key cryptography to authenticate the remote computer and allow the remote computer to authenticate the user, if necessary.
SSH is typically used to log into a remote machine and execute commands, but it also supports tunneling, forwarding arbitrary TCP ports and X11 connections; it can transfer files using the associated SFTP or SCP protocols.

now, in this posting i'll describe some usage from ssh client for tunnelling:

• X11 Display forwarding

• This type tunnel can be done with this additional command line:
  -X
  example:
  ssh -l wafa@myserver -X
• This methode explain that, all my display will exported to my local X Server, with note that you have install your local XServer (for windows you can install XWin32 or eXceed or another XServer for win32, but for linux/unix this is preinstalled package when u install desktop environment)