This policy setting allows you to specify if the Triple DES (3DES) cipher can be used to encrypt data sent over the Mobile ...

"This policy setting allows you to specify if the  Triple DES (3DES) cipher can be used to encrypt data sent over the Mobile VPN.  If you enable this setting, the Mobile VPN  can use 3DES data encryption.  If you disable this setting, the Mobile VPN  cannot use 3DES data encryption.  If you do not define this policy setting, the default behavior is to allow both AES and 3DES encryption.  Note: If both AES and 3DES encryption are explicitly not allowed, the Mobile VPN fails."