What is the basic difference between NMS and EMS in telecom domain ?

Question

I work in LTE technology want to know about these terms and also looking how LTE nodes are associated with EMS and NMS ?
Any example would help me.

Answer 1

EMS stands for "Entity Management System". It manages one Network Element or similar type of network element but NMS is one level ahead in the hierarchy and it manages the EMS . When data traffic need to pass from one network element to another network element then it leverages the interface that is exposed towards NMS.

In short, one NMS may contains various EMS.