
Chapter 4: Feature Description
Ethernet Features
Figure 31 MEF Ethernet Virtual Private LAN Example
E-Tree Service
The E-Tree service type is an Ethernet service type that is based on Rooted-Multipoint EVCs. In its
basic form, an E-Tree service can provide a single Root for multiple Leaf UNIs. Each Leaf UNI can
exchange data with only the Root UNI. A service frame sent from one Leaf UNI cannot be delivered
to another Leaf UNI. This service can be particularly useful for Internet access, and video-over-IP
applications such as multicast/broadcast packet video. One or more CoS values can be associated
with an E-Tree service.
Figure 32 E-Tree Service Type Using Rooted-Multipoint EVC
Two or more Root UNIs can be supported in advanced forms of the E-Tree service type. In this
scenario, each Leaf UNI can exchange data only with the Root UNIs. The Root UNIs can
communicate with each other. Redundant access to the Root can also be provided, effectively
allowing for enhanced service reliability and flexibility.
Page 4-26