Key MEF Terminology

All to One Bundling
A UNI attribute in which all CE-VLAN IDs are associated with a single EVC.

Bundling
A UNI attribute in which more than one CEVLAN ID can be associated with an EVC.

CE
Customer Equipment

CE-VLAN CoS
Customer Edge VLAN CoS. The user priority bits in the IEEE 802.1Q Tag in a Service Frame that is either tagged or priority tagged.

CE-VLAN ID
Customer Edge VLAN ID. The identifier derivable from the content of a Service Frame that allows the Service Frame to be associated with an EVC at the UNI. The identity of the VLANs on the Ethernet port of the customer equipment that is attached to the UNI.

CE-VLAN ID Preservation
An EVC attribute in which the CE-VLAN ID of an egress Service Frame is identical in value to the CE-VLAN ID of the corresponding ingress Service Frame.

CE-VLAN Tag
Customer Edge VLAN Tag. The IEEE 802.1Q Tag in a tagged Service Frame.

Class of Service (CoS)
A set of Service Frames that have a commitment from the Service Provider to receive a particular level of performance.

Committed Burst Size (CBS)
CBS is a Bandwidth Profile parameter. It limits the maximum number of bytes available or a burst of Service Frames sent at the UNI speed to remain CIR-conformant.  It defines the average rate in bits per second of ingress Service Frames up to which the network delivers Service Frames and meets the performance objectives defined by the CoS Service Attribute.

Committed Information Rate (CIR)
CIR is a Bandwidth Profile parameter. It defines the average rate in bits, of ingress Service Frames up to which the network delivers Service Frames and meets the performance objectives defined by the CoS Service Attribute. A Bandwidth Profile property where a pre-determined level of Bandwidth Profile compliance for each Service Frame, if present, is ignored when determining the level of compliance for each Service Frame.

Customer Edge
Equipment on the Subscriber side of the UNI.

E-LAN
An Ethernet service type that is based on a Multipoint-to-Multipoint EVC.

E-Line
An Ethernet service type that is based on a Point-to-Point EVC.

E-Tree
An Ethernet service type that is based on a Routed Point-to-Multipoint EVC.

E-NNI
External Network-to-Network interface that provides a Demarcation point between two service providers. A reference point where 2 Service Providers meet in support of specified MEF Services. For E-LAN and E-line services, but not E-Tree.

E-LMI
Ethernet Local Management Interface (A layer 2 control protocol).

EBS
Excess Burst Size.

EPL
Ethernet Private Line.

Ethernet Virtual Connection (EVC)
An association of two or more UNIs that limits the exchange of frames to UNIs in the EVC.

EVC Maximum Transmission Unit Size
The maximum sized Service Frame allowed for an EVC.

EVPL
Ethernet Virtual Private Line.

Excess Information Rate (EIR)
EIR is a Bandwidth Profile parameter. It defines the average rate in bits per second of ingress Service Frames up to which the network may deliver Service Frames without any performance objectives. The rate up to which the network will attempt to deliver Ethernet Service Frames before they are discarded.

GARP
Generic Attribute Registration Protocol (A layer 2 control protocol).

Ingress
The direction from the Customer Equipment (CE) into the ServiceProvider network.

Ingress Bandwidth Profile
A characterisation of ingress Service Frame arrival times and lengths at the ingress UNI and a specification of disposition of each Service Frame based on its level of compliance with the characterisation.

LACP
Link Aggregation Control Protocol (A layer 2 control protocol).

LAMP
Location Aware MAC Protocol (A layer 2 control protocol).

Layer 2 Control Protocol Service Frame
A Service Frame that is used for Layer 2 control.

Link OAM (IEEE 802.3ah)
Allows customer and service provider to monitor and diagnose the UNI connectivity via Link OAM (link level)

Link Protection (IEEE 802.3ad -LAG)
Service Protection (IEEE 802.1D - STP/MSTP)

LLDP
Link Layer Discovery Protocol (A layer 2 control protocol).

MRP
Metro Ring Protocol (A layer 2 control protocol).

MSTP
Multiple Spanning Tree Protocol.

OAM
Operations, Administration and Maintenance.

PE
Provider Edge.

Point-to-Point EVC
An EVC with exactly 2 UNIs.

QoS
Quality of Service providing Bandwidth Profiles, and Performance Delay / Jitter Loss Availability

RSTP
Rapid Spanning Tree Protocol.

Service Multiplexing
A UNI attribute in which the UNI can be in more than one EVC instance.

Service OAM (IEEE 802.1ag & ITU-T Y.1731)
Allows customer and service provider to monitor and diagnose the UNI connectivity via Service OAM (end-to-end).

STP
Spanning Tree Protocol.

End User
The organisation or customer purchasing and / or using ethernet services.

User Network Interface (UNI)
The User Network Interface is the physical interface or port that is the demarcation between the customer and the service provider. The physical demarcation point between the responsibility of the service provider and the responsibility of the subscriber.

User Network Interface (UNI-C & UNI-N):
There are two functional elements (typically*) located in two connected devices situated on either side of the UNI demarcation point. UNI-C executes the processes of the customer side -  UNI-N executes the processes of the network side. All the functions of the UNI-N and UNI-C need not be located in the same physical device as they may be located in several devices.

User Network Interface (UNI) Type 1 (defined in MEF 13)
Service Provider and Customer manually configure the UNI-N and UNI-C for services

User Network Interface (UNI) Type 2 (defined in MEF 20)
Adds additional fault management and protection functionality with automated implementation allowing UNI-C to retrieve EVC status and configuration information from UNI-N. UNI Type 2.1 and 2.2 are defined Backward compatibility with UNI Type 1