An E-Line service as defined by the MEF is for connecting exactly two UNIs where those two UNIs can communicate only with one another. This is based on Point-to-Point Ethernet Virtual Connections (EVCs). The service can be delivered port-based (EPL) or VLAN-based (EVPL). EPL is ideal for replacing legacy E1 leased lines and EVPL is ideal for replacing legacy frame relay circuits.
An E-LAN service as defined by the MEF is for connecting two or more UNIs providing full mesh connectivity for those sites. This is based on Multipoint-to-Multipoint EVCs. The service can be delivered port-based (EP-LAN) or VLAN-based (EVP-LAN). E-LAN is ideal for replacing multipoint IP-VPN and ATM TLS services and EP-LAN provides transparent extension of the LAN over the WAN.
An E-Tree service as defined by the MEF is for connecting a number of UNIs providing sites with a hub and spoke topology. Each UNI is designated as either root or leaf. A root UNI can communicate with any leaf UNI, while a leaf UNI can communicate only with a root UNI. This is based on a Rooted Multipoint EVC. The service can be delivered port-based (EPTree) or VLAN-based (EVP-Tree). E-Tree is ideal for residential broadband providers where UNI to UNI connectivity is not desired.