The Ethernet LAN (E-LAN) service type is illustrated in Figure 2.11.
An E-LAN service connects two or more UNIs and service frames sent from one can be
received at one or more of the other UNIs. In an E-LAN service, each UNI is connected
to a multipoint EVC (even an E-LAN service connected to two UNIs is comprised of a
multipoint EVC and hence, not an E-LINE service, which has a Point-to-Point EVC).
An E-LAN can be used to create a broad range of services. In its simplest form, an
E-LAN service type can provide a best effort service with no performance assurances
between the UNIs. In more sophisticated forms, an E-LAN service type may be defined
with performance assurances such as CIR with an associated CBS and EIR with an
associated EBS for a given CoS instance. The MEF has not defined service performance
(delay, delay variation, and loss) attributes for the E-LAN service type.
For an E-LAN service type, Service multiplexing may occur at neither, one, or more
of the UNIs in the EVC. For example, an E-LAN service type (Multipoint-to-Multipoint
Figure 2.10 Ethernet Line (E-LINE) service type (Source: MEF)
Point-to-Point EVC
UNI
MEN
UNI CE
CE
Carrier Ethernet 71
EVC) and an E-LINE service type (Point-to-Point EVC) may be service multiplexed at
the same UNI.
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