Difference between EMS and NMS

1. Element Management System (EMS) :
Element Management System (EMS), as name suggests, is a software tool that is generally used to manage all network elements. Here element represent node i.e. device such as computer, router, etc.

2. Network Management System (NMS) :
Network Management System (NMS), as name suggest, is a software tool that is generally used to manage and control network i.e. interconnected nodes.

Difference between EMS and NMS :

EMS	NMS
EMS usually manages single element or group of similar elements. Elements simply refers to node.	NMS usually manages more than one network i.e. multiple networks. Network simply refers to interconnected nodes.
EMS does not able to understand communication relationship among devices or elements.	NMS has ability to better understand communication and relationship among devices or elements.
EMS only have detail about complicated parts of single element.	NMS have detail about complicated parts of all elements.
EMS does not have any capability to manage different types of nodes or elements that have different functions, different nature.	NMS have capability to manage different types of nodes or elements that have different functions, different nature.
EMS can have access to complete management information content of all network elements within its domain or network.	NMS are not allowed to have access to complete management information content of all network elements within its domains or networks.
EMS cannot contain any NMS.	NMS can contain many EMS and can also manage them.
Protocols used to support management are SNMP, CORBA, XML, etc.	Protocols used to support management are SNMP, JMX, etc.
EMS does not monitor interconnection or connecting links between elements.	NMS monitors interconnection or connecting links between elements.
It does not report any fault or problems occurring at different nodes within network.	It reports all fault or problems occurring at different nodes or elements within network.
EMS cannot identify faults at different nodes and therefore cannot predict how fault is affecting communication link leading to non-functioning of whole network.	NMS can identify faults at different nodes and therefore can predict how fault is affecting communication link leading to non-functioning of whole network.