MPLS L3VPN & L2VPN

Hi LSA,

Both technologies are different enough and it is apparent that neither is going to defeat the other. From an ISP perspective, this makes possible to use them according to his own strategies and market requirements. From a customer perspective, both MPLS services allows them to securely connect geographically diverse sites across a public telecommunications infrastructure at a relatively low cost.
The differences to consider from both perspectives are the following:
1. In L2VPN case, no routing interaction occurs between the customer and service provider (CE switch forward traffic to ISP PE in layer 2 format, customer has complete control over his policies and routing). In L3VPN case, the customer must share (BGP/OSPF) information about his network topology (the ISP determines the policies and routing, outsourcing of routing tables can be seen as a weakness).
2. In L2VPN case, the customer can run any type of Layer 3 protocol between his sites (non-IP protocols such as IPX or SNA could be used).
3. Operative costs for ISPs is higher when deploying L3VPN due to the resources required on the devices that work as CE and PE.

Hence, in order to address the widest possible market, many service provider offer both services over their MPLS infrastructure.

Hello @LSA

As the graph below shows, MPLS L2VPN provides a layer 2 connection between CEs, while MPLS L3VPN provides a layer 3 connection between CEs.

In a L2VPN network, it's not necessary to switch customers' routes with PE router, so it provides a better privacy and low resource cost on PE router.

Since VRF is required on PEs for each CE in L3VPN, so it will requires more hardware resource than L2VPN does.

Additionally, since the L2VPN provides the layer 2 connection, it allows the users to run more protocols which run on layer 2 link, while L3VPN doesn't.

L3VPN could prevent the broadcast storm on the network, while L2VPN cannot.
Broadcast storm will heavily lower down the devices' performance, causing the whole network performance down.

Interesting stuff.