CDP and LLDP information are polled by SNMP. Of course the device have to have one of them running and detecting peers for it to work. The majority of the complexity of NTM is in how we detect topology when CDP and LLDP are not available. We use MAC tables, ARP tables, and route tables in those cases. While we detect many links this way, it's much, much harder than CDP and LLDP which leads to less completeness and accuracy.
NTM does not currently use any CLI based polling.