What is Multiprotocol Label Switching (MPLS)?

Multiprotocol Label Switching (MPLS) is data forwarding technology that increases the speed and controls the flow of network traffic. With MPLS, data is directed through a path via labels instead of requiring complex lookups in a routing table at every stop.

Scalable and protocol independent, this technique works with Internet Protocol (IP) and Asynchronous Transport Mode (ATM).

When data enters a traditional IP network, it moves among network nodes based on long network addresses. With this method, each router on which a data packet lands must make its own decision, based on routing tables, about the packet’s next stop on the network. MPLS, on the other hand, assigns a label to each packet to send it along a predetermined path.

Label Switched Paths (LSPs) are predetermined, unidirectional paths between pairs of routers across an MPLS network.

1. When a packet enters the network through a Label Edge Router (also known as an “ingress node”), it is assigned to a Forwarding Equivalence Class (FEC), depending on the type of data and its intended destination. FECs are used to identify packets with similar or identical characteristics.
2. Based on the FEC, the ingress node will apply a label to the packet and encapsulate it inside an LSP.
3. As the packet moves through the network’s “transit nodes” (also known as Label Switch Routers), those routers continue to direct the data by the instructions in the packet label. These in-between stops are based on the packet label, not additional IP lookups.
4. At the “egress node,” or final router at the end of the LSP, the label is removed and the packet is delivered via normal IP routing.

A label stack is made up of at least four parts:

Label value: holds the information for routers to determine where the packet should go next

Traffic class field: sets Quality of Service priority and Explicit Congestion Notification

Bottom of stack flag: indicates the last label in the stack

Time-to-live (TTL) field: limits the lifespan of the data, or how many hops it can make before it’s discarded

Labels can also be stacked. The top label controls packet delivery; when it reaches its destination, that label is “popped,” and the label underneath takes over for direction.

MPLS is considered a layer 2.5 networking protocol. Layer 2 carries IP packets over simple LANs or point-to-point WANs, while layer 3 uses internet-wide addressing and routing using IP protocols. MPLS sits in between, with additional features for data transport across the network.

SD-WAN: An Emerging Alternative

SD-WAN is an application of software to make Wide Area Networking more intelligent and flexible while taking advantage of commodity broadband links to the internet. In addition, policies can be easily applied across all WAN devices rather than necessitating manual creation of predetermined routes, as with MPLS.

If your WAN traffic consists of non-real-time applications, or if real-time is hosted on the cloud, SD-WAN benefits can include:

• Lower costs
• Increased bandwidth
• Higher performance
• More uptime
• Better performance at small, remote, or international sites
• Quicker provisioning and rollout

Forcepoint offers the latest in SD-WAN technology all managed at enterprise scale from a centralized, single-policy console. It can replace your MPLS today and give you the flexibility, security and scale you need to manage your network.