A label switching router is a router that supports and understands Multiprotocol Label Switching (MPLS), a type of networking that routes traffic based on labels. Unlike traditional Internet Protocol (IP) address-based forwarding, MPLS is faster and can handle heavy Internet traffic. The routing method helps balance traffic and optimize network resources.

Label switching routers play a huge role in delivering MPLS packets to their designated routes. To better understand what a label switching router is, pretend you’re on an unfamiliar highway. If you’re not sure where you’re going, road signs are a big help. MPLS packets are like travelers having a hard time finding the correct routes. A label switching router acts like road signs, guiding MPLS packets to their right destination.

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Label switching routers can quickly screen labels and forward the packets to their respective destinations. Unlike a traditional router, they don’t have to check and compute data every time they route packets.

There are some important networking concepts to understand to fully grasp what label switching routers are. These are MPLS and labels.

What Is a Data Packet Label?

Data packet labels contain information about the type of traffic the packet is carrying. It tells the router if it’s transporting voice, video, email, or other forms of data. A label switching router would then route the data depending on this information.

What Is MPLS?

MPLS is a networking technology that uses labels to guide data packets to their correct destinations.

Traditionally, networks route traffic based on the data packet’s IP header. However, this method takes time since the router would need to analyze the IP address information of all data packets at every point of data transmission. 

With MPLS, traffic is segregated based on the type of data specified on the label. They are then assigned to a Forwarding Equivalence Class (FEC), which determines the route they’re going to take. 

FEC can be “real-time” for voice and video traffic, “best effort” for traffic carrying browsing and email data, or “mission-critical” for certain application data, such as traffic from and to customer relationship management (CRM) platforms.

What Are the Four Types of Label Switching Routers?

The four types of label switching routers are:

  • Ingress router: From the word “ingress,” this type of label switching router serves as the entry point for incoming traffic. 
  • Transit router: The transit router is responsible for switching MPLS packets to the next path. It has multiple network communication and route management features.
  • Penultimate router: As the packet enters an MPLS tunnel, it pushes a second label onto the stack. The penultimate router is responsible for popping the second label before traveling to another transit router.
  • Egress router: An egress router is located at the endpoint. It is where the traffic exits and leaves the router to go and hit the Local Area Network (LAN).

What Are the Benefits of Using Label Switching Routers?

Using a label switching router has several advantages, including:

  • Fast and efficient: Unlike traditional IP-based forwarding, label switching routers are proven to perform faster. They help reduce delays in sending packets through the network and also increase network bandwidth.
  • Scalable: With billions of Internet users every day and counting, routing traffic can become heavy. Label switching routers help solve this problem by accommodating numerous IP addresses to be linked with one or a few labels.
  • Simple: The role of label switching routers is to forward MPLS packets quickly into traffic, hassle-free. It doesn’t let packets jump around to check and compute data, which causes delays.
  • Convenient and cost-effective: With label switching routers, users can add new remote connections without having to buy new hardware. This helps save money.

What Are the Challenges in Using Label Switching Routers?

There are specific challenges when using label switching routers. For one, they were primarily designed to connect organizations with multiple locations via enterprise data centers. These days, most entities use cloud services so traffic comes from and to these cloud service providers.

Label switching routers also require a Wide Area Network (WAN) connection, which is usually more expensive than using Ethernet.

MPLS has been a game-changer in the telecommunications and networking industries, and label switching routers make it possible.