Often discussed in the same breath, virtual private networks (VPNs) and multiprotocol label switching (MPLS) are not one and the same. One is a network; the other is a network mechanism. Here's a quick look at the primary differences between VPN and MPLS.
What is a Virtual Private Network?
VPNs are computer networks which are "virtual" in that they are layered on top of a physical network. The VPN's network data is separated from that of the Internet as a whole, making for a private pipeline that travels through the Internet within the VPN.
A VPN uses the Internet or some other shared public telecom infrastructure to provide remote offices and their users with a secure network. Though a shared infrastructure is involved, VPNs use tunneling protocols to create secure connections. For example, think of the Internet as if it were a giant tunnel. When using the Internet, all traffic goes through this tunnel. Now imagine a company wanting to have its own pipeline inside this tunnel. By creating a VPN, the company can still use the Internet; however, its private data is routed through its own private pipe. Thus, a virtual private network is created within the larger tunnel. From a technical perspective, this involves tunneling the lower Internet Protocol (IP) layers through the transport network layer.
What is Multiprotocol Label Switching?
Multiprotocol label switching is not a computer network. Rather, it's a standards-based technology that is used to move network packets traffic from one node to another - over different protocols such as Internet Protocol, frame relay, or Asynchronous Transport Mode (ATM). It is a protocol-independent mechanism that directs and carries data from one network node to the next. MPLS labels data packets, which eliminates the need to determine what's inside each packet and enables a more efficient means of transmitting data. Rather than looking at packets individually and then making forwarding decisions, MPLS labels are used to make the forwarding decisions. Layer 3 analysis takes place just once with label inspection then kicking in to drive forwarding. With MPLS labeling, users are no longer dependent on specific technologies and protocols.
Also called the "Layer 2.5 protocol," MPLS works at the OSI Model layer. This layer is found between Layer 2 and Layer 3 (the Data Link Layer and the Network Layer respectively). MPLS is a versatile mechanism that carries data and numerous types of traffic.
What is a MPLS VPN?
Though they are distinct technologies, the terms MPLS and VPN are often used interchangeably or together. Part of the confusion stems from the term MPLS VPN which refers to a virtual private network that is built on top of a multiprotocol label switching network. MPLS VPNs are typically provided to an enterprise from a third party provider to create a secure connection between branch offices.
Though one is a computer network and the other is a mechanism, VPNs and MPLS can work together to create a private virtual network that is extremely efficient at labeling and delivering network packets.
Maxwell Pierce is a WAN Optimization specialist. He strongly believes in the future of MPLS and VPN to solve distributed enterprise' networks performance issues.
