MPLS VPN over mGRE design and implementation for a service provider's network using GNS3 simulator

MPLS VPN over multipoint GRE supports the flexibility that point-to-multi point MPLS VPN over IP technique offers, while clarifying network operations to a great extent. This feature simplifies management, configuration and reduce expenses for having best quality of service of any service provider. As mGRE is a point-to-multipoint model, fully meshed GRE tunnels are not required to interconnect MPLS VPN provider edge devices and thus, MPLS VPN over mGRE solves the time consuming complex configurations of service providers for connecting hundreds of sites which are spread over different locations, requiring a full-mesh of connectivity and the IGP and LDP needed to run over them. In this paper, we have implemented the idea over a service provider's core network using Graphical Network Simulator (GNS3). When the MPLS VPN over mGRE feature is enabled, it allows one to provision the L3 VPN services without using Label-Switched Path (LSP), Carrier Supporting Carrier (CsC), or a Label Distribution Protocol (LDP). MPLS VPN over mGRE feature uses IPv4-based mGRE tunnels to encapsulate VPNv4/v6 labeled packets between customer edge devices, over the IP transport. In the new era of service provider's network, this design will be the solution many complex situations and open a new door to meet up customer's increasing in a scalable way.

I. Introduction

MPLS is an extensively deployed VPN internet architecture. It requires that all backbone routers in the network support MPLS. This feature is useful in service providers' networks, where they use a backbone carrier to provide connectivity [1]. On the other hand, GRE is a point-to-point tunneling protocol. Here, two peers form the endpoints of the tunnel. It is designed to encapsulate network-layer packets inside IP tunneling packets. mGRE is a similar protocol with a single endpoint at one side of the tunnel connected to multiple endpoints at the other side of the tunnel [1]. While establishing connectivity among many offices like, hundreds of branch offices, the mGRE tunnel provides a common link among those offices that connect to the same VPN.