Cambium Networks PTP 820S, Техническое описание, Страница: 55 / 208

Chapter 4: Feature Description Ethernet Features
Since service multiplexing is permitted in EVPL services, some service frames may be sent to one
EVC while others may be sent to other EVCs. EVPL services can be used to replace Frame Relay
and ATM L2 VPN services, in order to deliver higher bandwidth, end-to-end services.
Figure 26 EVPL Application Example
E-LAN Service
The E-LAN service type is based on Multipoint to Multipoint EVCs, and provides multipoint
connectivity by connecting two or more UNIs. Each site (UNI) is connected to a multipoint EVC,
and customer frames sent from one UNI can be received at one or more UNIs. If additional sites
are added, they can be connected to the same multipoint EVC, simplifying the service activation
process. Logically, from the point of view of a customer using an E-LAN service, the MEN can be
viewed as a LAN.
Figure 27 E-LAN Service Type Using Multipoint-to-Multipoint EVC
The E-LAN service type can be used to create a broad range of services. In its basic form, an E-LAN
service can provide a best effort service with no performance assurances between the UNIs. In
more sophisticated forms, an E-LAN service type can be defined with performance assurances
such as CIR with an associated CBS, EIR with an associated EBS, delay, delay variation, loss, and
availability for a given CoS instance.
For an E-LAN service type, service multiplexing may occur at none, one, or more than one of the
UNIs in the EVC. For example, an E-LAN service type (Multipoint-to-Multipoint EVC) and an E-Line
service type (Point-to-Point EVC) can be service multiplexed at the same UNI. In such a case, the E-
LAN service type can be used to interconnect other customer sites while the E-Line service type is
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