First I will explain the difference between them:
- Lite Touch Installation (LTI) is used when F12 must be pressed on the local device during PXE boot the device;
- Zero Touch Installation (ZTI) is used when nothing has to do be done on the local device for PXE boot functionality.
When using Windows Deployment Services (WDS) and/or Microsoft Deployment Toolkit (MDT), Lite Touch functionality is possible. With the use of System Center Configuration Manager (ConfigMgr), Zero Touch functionality will also become available. Both scenarios are handy, and will be used by customers. The choice between them, has something to do with Management, BIOS settings and (remote) locations.
Now let's have a look at the advertise/deploy settings:
When advertise/deploy an OS Deployment Task Sequence, choose "Make this task sequence available to boot media and PXE".
On the next screen create a Mandatory assignment when ZTI is needed. This will make the big difference between LTI and ZTI, a Mandatory assignment!
For having ZTI, also the PXE boot order must be set. When the Network adapter is not in first place, there is no ZTI possible. Also decide on which collection ZTI deployment will be advertised/deployed. This is not recommended on most collections, so create a new collection, specific for ZTI deployments!
On the ConfigMgr PXE service point, additional properties can be set. When "Require a password for computers to boot using PXE" is selected, no ZTI deployment is possible also. This will be become handy with LTI deployment, when pressing F12 for PXE boot, a password is needed to get a new OS image.
Also a big difference; with LTI a device can be installed many times again with a new image, without anything to do with the device in ConfigMgr collections. Only make sure that the device is placed in the right collection, where the advertisement is set.
With ZTI a device gets a PXE advertisement on the device in ConfigMgr collections, to prevent it for being installed over and over again. When a device must get a new OS image, just rightclick on the object, and choose "Clear Last PXE Advertisement. When this is done, the advertisement will become active automatically with next boot.
When will LTI or ZTI be the best solution? It depends..
When total control is needed, Password security, Choose between different OS images, Another boot order (harddisk or USB first), LTI will be the best solution there is. When remote OS deployment is needed, Auto-install on remote locations, Wake-On-LAN support, No interaction on the device, ZTI will be the best solution there is.
Do not hesitate when things are not clear enough, or additional questions are left. Just leave a comment then.