MEF Introduction
May 2015, ver3
Agenda
• Basic Ethernet Service Model
• Ethernet Virtual Connection & types
• E-LINE service
• EPL – Ethernet Private Line service
• E-LAN service
• E-Three service
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Basic Ethernet Service model
CE – Customer Equipment (router, switch/bridge or host end system
UNI – User Network Interface is point between customer and provider network
MEN – Metro Ethernet Network – transport technology as SDH/SONET,
Ethernet, ATM, MPLS and GFP
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EVC – Ethernet Virtual Connection
Connectivity between UNIs is defined as an Ethernet Virtual Connection (EVC)
An EVC is defined by the MEF as an association of two or more UNIs that limits the
exchange of service frames to UNIs in the Ethernet Virtual Connection. The EVC perform
two main functions:
• Connects two or more customer sites (UNIs), enabling the transfer of Ethernet frames
between them.
• Prevents data transfer involving customer sites that are not part of the same EVC. This
feature enables the EVC to maintain a secure and private data channel.
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EVC types:
1. Point to Point EVC – Each EVC contains exactly two UNIs. The
following figure shows two point-to-point EVCs connecting one site to
two other sites.
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EVC types:
2. Multipoint (Multipoint-to-Multipoint) EVC – Each EVC contains two
or more UNIs. In the figure below, three sites belong to a single
Multipoint EVC and can forward Ethernet frames to each other.
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EVC types:
3. Rooted Multipoint EVC (Point-to-Multipoint) – Each EVC contains
one or more UNIs, with one or more UNIs defined as Roots, and the
others defined as Leaves. The Roots can forward frames to the Leaves.
Leaves can only forward frames to the Roots, but not to other Leaves.
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Ethernet Services Definitions
• Ethernet service types are generic constructs used to create a broad range
of services. Each Ethernet service type has a set of Ethernet service
attributes that define the characteristics of the service. These Ethernet
service attributes in turn are associated with a set of parameters that
provide various options for the various service attributes.
• The MEF defines three generic Ethernet service type constructs, including
their associated service attributes and parameters:
• Ethernet Line (E-Line)
• Ethernet LAN (E-LAN)
• Ethernet Tree (E-Tree)
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E-Line – Ethernet Line
• The Ethernet line service (E-Line service) provides a point-to-point Ethernet
Virtual Connection (EVC) between two UNIs.
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EPL - Ethernet Private Line Service
• An Ethernet Private Line (EPL) service is specified using an E-Line Service
type. An EPL service uses a point-to-point EVC between two UNIs and
provides a high degree of transparency for service frames between the
UNIs that it interconnects such that the service frame’s header and payload
are identical at both the source and destination UNI when the service frame
is delivered (L1 service). A dedicated UNI (physical interface) is used for the
service and service multiplexing is not allowed.
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EVPL - Ethernet Virtual Private Line Service
• An Ethernet Virtual Private Line (EVPL) is created using an E-Line service
type. An EVPL can be used to create services similar to EPL services.
However, several characteristics differ between EPL and EVPL services.
• First, an EVPL provides for service multiplexing at the UNI, which means it
enables multiple EVCs to be delivered to customer premises over a single
physical connection (UNI). In contrast, an EPL only enables a single service
to be delivered over a single physical connection.
• Second, the degree of transparency for service frames is lower in an EVPL
than in an EPL.
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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.
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Difference between E-Line and E-LAN
• If in E-Line service is a new site (UNI) is added, it is necessary to add a new, separate EVC to
all of the other sites in order to enable the new UNI to communicate with the other UNIs, as
shown in the following figure.
• When is used an E-LAN service, it is only necessary to add the new UNI to the multipoint EVC.
No additional EVCs are required, since the E-LAN service uses a multipoint to multipoint EVC
that enables the new UNI to communicate with each of the others UNIs.
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Ethernet Private LAN Service
• Customers commonly require a highly transparent service that connects multiple UNIs. The
Ethernet Private LAN (EP-LAN) service is defined with this in mind, using the E-LAN service
type.
• The following figure shows an example of an EP-LAN service in which the service is defined to
provide Customer Edge VLAN (CE-VLAN) tag preservation and tunneling for key Layer 2
control protocols. Customers can use this service to configure VLANs across the sites without
the need to coordinate with the service provider. Each interface is configured for All-to-One
Bundling, which enables the EP-LAN service to support CE-VLAN ID preservation. In addition,
EP-LAN supports CE-VLAN CoS preservation.
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Ethernet Virtual Private LAN Service
• Customers often use an E-LAN service type to connect their UNIs in an MEN, while at the same
time accessing other services from one or more of those UNIs. For example, a customer might
want to access a public or private IP service from a UNI at the customer site that is also used to
provide E-LAN service among the customer’s several metro locations. The Ethernet Virtual
Private LAN (EVP-LAN) service is defined to address this need. EVP-LAN is actually a
combination of EVPL and E-LAN.
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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.
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Ethernet Private Tree Service
• The Ethernet Private Tree service (EP-Tree) is designed to supply the flexibility for configuring
multiple sites so that the services are distributed from a centralized site, or from a few
centralized sites. In this setup, the centralized site or sites are designed as Roots, while the
remaining sites are designated as Leaves. CE-VLAN tags are preserved and key Layer 2
control protocols are tunneled. The advantage of such a configuration is that the customer can
configure VLANs across its sites without the need to coordinate with the service provider. Each
interface is configured for All-to-One Bundling, which means that EP-Tree services support CE-
VLAN ID preservation. EP-Tree also supports CE-VLAN CoS preservation. EP-Tree requires
dedication of the UNIs to the single EP-Tree service.
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Ethernet Virtual Private Tree Service
• In order to access several applications and services from well-defined access points (Root), the
UNIs are attached to the service in a Rooted Multipoint connection. Customer UNIs can also
support other services, such as EVPL and EVP-LAN services. An EVP-Tree service is used in
such cases. Bundling can be used on the UNIs in the Rooted Multipoint EVC, but it is not
mandatory. As such, CE-VLAN tag preservation and tunneling of certain Layer 2 Control
Protocols may or may not be provided. EVP-Tree enables each UNI to support multiple
services. A good example would be a customer that has an EVP-LAN service providing data
connectivity among three UNIs, while using an EVP-Tree service to provide video broadcast
from a video hub location. The following figure provides an example of a Virtual Private Tree
service.
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Where are we with IP-20?
IP-20 Packet Service Core Building Blocks
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Universal Packet Backhaul Services Core
Any Service
• Ethernet services (EVCs)
• E-Line (Point-to-Point)
• E-LAN (Multipoint)
• E-Tree (Point-to-Multipoint)
• Port based (Smart Pipe) services
Any Transport
• Native Ethernet (802.1Q/Q-in-Q) and MPLS-TP
• Any topology and any mix of radio and fiber interfaces
• Seamless interworking with any optical network (NG-SDH, packet optical
transport, IP/MPLS service/VPN routers)
Fully Programmable and Future-Proof
• Network-processor-based services core
• Ready today to support emerging and future standards and networking
protocols
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Universal Packet Backhaul Services Core
Virtual Switching/Forwarding Engine
• Clear distinction between user facing service interfaces (UNI) and intra-
network interfaces
• Fully flexible C-VLAN and S-VLAN encapsulation
(classification/preservation/ translation)
• Improved security/isolation without limiting C-VLAN reuse by different
customers
• Per-service MAC learning with 128K MAC addresses support
Rich Policies and Tools with Unified and Simplified Management
• Personalized QoS (H-QoS)35
• Superb service OAM (CFM, PM)36
• Carrier-grade service resiliency (G.8032, MSTP)37
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Thank You
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