Metro Ethernet

metro-ethernet-services

Metro Ethernet Overview

Simply, Metro Ethernet is an enhanced version of Ethernet that is used between long distances with higher bandwidths. Metro Ethernet can be used both by companies to connect their sites and by end users to connect Internet.

Ethernet is a wellknown and widely used Local Area Network (LAN) standard. At the beginning, it was only used for Local area Networks (LANs), for limited distances and limited bandwidths. But with the development of Ethernet Standards, Ethernet have started to be used by Carriers for MAN (Metropolitian Area Network) and WAN (Wide Area Network). These high capacity Ethernet called Carrier Ethernet. And Carrier Ethernet used for MAN (Metropolitian Area Network) is called Metro Ethernet.

 


 

Metro Ethernet Services

In Metro Ethernet technology there are different types Services. These services types are:

  • E-Line (Ethernet Line Service)
  • E-LAN (Ethernet LAN Service)
  • E-Tree (Ethernet Tree Service)
  • E-Access (Ethernet Access Service)

 

These services can be used with one circuit per interface or with multiple circuit per interface with the help of VLANs. In other words, one interface can carry one more Metro Ethernet service traffic. According to these, above Service types has sub names like given below:

Service, Interface Based, VLAN Based

  • E-Line, Ethernet Private Line (EPL), Ethernet Virtual Private Line (EVPL)
  • E-LAN, Ethernet Private LAN (EP-LAN), Ethernet Virtual Private LAN (EVP-LAN),
  • E-Tree, Ethernet Private Tree (EP-Tree), Ethernet Virtual Private Tree (EVP-Tree),
  • E-Access, Access Ethernet Private Line (Access EPL), Access Ethernet Virtual Private Line (Access EVPL).

Let’s talk bout detailly on each Metro Ethernet Service.

 


 

E-Line (Ethernet Line Service)

E-Line is the simplest Metro Ethernet service that is a point-to-point connection between two nodes. This point-to-point connection is called Ethernet Virtual Circuit (EVC). Here, customer connect to the provider device via Ethernet from one point and provider transmits the customer traffic to the other point over its network. At the other end customer is also connected to the service provider via Ethernet. Customer locations are connected as Layer 2 with E-Line Service and it is like a Leased Line between customer locations.

Point-to-Point connections use one interface at each part. On that interface one or one more EVC can be used according to need. If we use one EVC per interface, this is called Ethernet Private Line (EPL). If we use one more EVC on a single interface, we need to use dot1q protocol, VLANs to differentiate different EVCs. This is called Ethernet Virtual Private Line (EVPL).


e-line-vpws-topology
 

If Service Provider uses MPLS on its network, this Metro Ethernet service is called VPWS (Virtual Private Wire Service). We have talked about VPWS in Nokia (formarly Alcatel-Lucent) Services Architecture Course detailly.

 


 

E-LAN (Ethernet LAN Service)

E-LAN is the Metro Ethernet service that is a multipoint-to-multipoint connection between two or more nodes. In this type of connection, customer has two or more locations and with E-LAN, customer locations are connected over Service Provider network as all these locations are in the same network. Customer locations are connected as Layer 2 with E-LAN Service and it is like a LAN that connects customer locations.

Like E-Line, in E-LAN there can be one or one more E-LAN definion on one interface. If we use one E-LAN per interface, this is called Ethernet Private LAN (EP-LAN). If we use one more E-LAN on a single interface, we need to use dot1q protocol, VLANs to differentiate different E-LAN. This is called Ethernet Virtual Private LAN (EVP-LAN).

The connections in E-LAN is Full Mesh. So, if we have N branches, we should use N x (N-2)/2 connections. With full mesh, as you know all the brances are connected to the others.


e-lan-vpls-topology
If Service Provider uses MPLS on its network, this Metro Ethernet service is called VPLS (Virtual Private LAN Service). We have talked about VPLS in Nokia (formarly Alcatel-Lucent) Services Architecture Course detailly.

 


 

E-Tree (Ethernet Tree Service)

E-Tree is the Metro Ethernet service that is a Hub and Spoke connection between nodes. In this type of connection, customer has central and spoke locations. Central locations is need to be accessed from the other nodes.


e-tree-topology
In E-Tree, acording to VLAN use, there are two E-Tree types. One is without VLAN, Ethernet Private Tree (EP-Tree) and the other VLAN based Ethernet Virtual Private Tree (EVP-Tree).

 


 

E-Access (Ethernet Access Service)

E-Access is the Metro Ethernet service that is used between Service Providers for interconnecting locations that is not in service providers own network. This approach provide a fast and efficient solution for the service providers that do not have coverage on that locations.


According to VLAN usage or not, there are two types E-Access. These are Access Ethernet Private Line (Access EPL) and Access Ethernet Virtual Private Line (Access EVPL).

 

Lesson tags: metro ethernet
Back to: CCIE Enterprise Infrastructure > WAN

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