To ssh root into your atv2 find out the IP of from your network setting on apple tv 2

1: ssh root@
You will then see this

The authenticity of host ' (' can't be established.
RSA key fingerprint is f4:81:56:ac:ae:ec:4a:60:a4:6a:ca:09:83:6d:4f:39.

2: Are you sure you want to continue connecting (yes/no)? yes
Warning: Permanently added '' (RSA) to the list of known hosts.

3: Enter the password root@'s password: =