This video show how to download and configure GNS3 VM for running Cisco IOU images. This also includes downloading and installing GN3 appliances form GNS3 marketplace to run Cisco IOS Over Unix.

When used with MPLS, the VPN feature allows several sites to interconnect transparently through a service provider's network. One service provider network can support several different IP VPNs. Each of these appears to its users as a private network, separate from all other networks. Within a VPN, each site can send IP packets to any other site in the same VPN. Each VPN is associated with one or more VPN routing and forwarding instances (VRFs). A VRF consists of an IP routing table, a derived Cisco express forwarding (CEF) table, and a set of interfaces that use this forwarding table. The router maintains a separate routing and CEF table for each VRF. This prevents information being sent outside the VPN and allows the same subnet to be used in several VPNs without causing duplicate IP address problems. In this document, we'll be configuring basic MPLS Layer 3 VPN for two customers, each having two physical sites at different location. Network Topology: ...

In this article, we will study how forwarding decisions are made in a MPLS Network. You can check out the configuration of the network at Creating Layer 3 MPLS VPN . Network Topology: