What to choose L2MPLS or L3MPLS

What to choose L2MPLS or L3MPLS 

Well this is very interesting article for the candidates who really are in the service provider domain or who study hard on the MPLS technologies and how MPLS technology is used in the enterprise network.

MPLS is always the core of the service provider and the connectivity from one PE router to another PE router will be via MPLS technology where you have internal routing protocol for data traffic like OSPF( Open shortest path First ) and IS-IS ( intermediate system to intermediate system ) and the concepts of the label which is handled by the protocol LDP/TDP ( Label distribution protocol or Tag distribution protocol ) and the control plane traffic flows from the indirectly connected MP-iBGP protocols between two PE routers across the globe of the single Service provider.

Audience # MPLS candidates, CCIE-SP candidates, NOC Engineers, TAC Engineers, Systems Engineer, System Architect and Network Engineers

So now question if MPLS is there in the core then what is the difference between L2MPLS and L3MPLS, Why they differ and how we can have these kinds of environment in the enterprise network. Well your question is genuine, while understanding the concept you should know about the concept of VPLS where L2 instances are shared rather than L3 instances with the service provider.

So the answer to your question is as follows:

L3 VPNs the routing for the customers is done by the Service Provider who maintains a VRF per customer or per L3VPN. It means customer sends the traffic in the form of Packets via CE router with the connectivity of the BGP protocol, It means pure routing is done at the edges of the MPLS network where PE-CE connectivity is there and traffic is like routing updates from the customer locations and need to connect to the other locations of the customer across the globe.

Fig 1.1 L3MPLS connectivity

In case of a L2VPN, the analogy can be like laying an Ethernet cable across the customer locations, where routing will be managed by the customer. So it means that routing information is not being shared to the service provider and the traffic will be received as frames or L2 traffic to the service provider and there is tunnel between one PE router to another PE router for the connectivity between one location to another.

Fig 1.2- L2MPLS Fundamental

So hope you understand the concept and the difference between L2MPLS and L3MPLS. So many of the customer in the enterprise network don't want to share the routing information, so they uses L2MPLS instead of L3MPLS but many of the customer uses L3MPLS now a days and its not like it is not secure, it is always secure.

There are lot of service provider across the globe who provides MPLS connectivity to the customers, Some of them are as shown below. Sorry if i missed MPLS providers, i knew many of the ISP's provide MPLS connectivity to the customer across the globe.

North America
  • AT&T : United States of America
  • Verizon : United States of America
  • CenturyLink : United States of America
  • Sprint : United States of America
  • Telus : Canada
  • Bell : Canada
South America
  • Sparkle
  • PCCW
  • Nextel
  • Global Crossing
  • Orange Business Services : France
  • BT Global Services : United Kingdom
  • Colt : United Kingdom
  • Vodafone : United Kingdom
  • SITA : France
  • T-Systems : Europe
  • Telefonica : Europe
  • KPN: Europe
  • NTT Communications 
  • Interroute
  • Easynet
Asia Pacific
  • Singtel : Singapore
  • Tata Communications : India
  • Bharti Airtel : India
  • Telstra Global : Australia
  • China Unicom : China
  • China Telecom : China
  • NTT Communications : Japan
  • Hutchison Global Services : Asia
  • Reliance : India