1. Introduction

In this tutorial, we’re going to discuss Multiprotocol Label Switching (MPLS),  Virtual Private LAN Service (VPLS), and the major differences between them. As networking technology plays a crucial role in enabling communication and data sharing between multiple devices, computers, and servers within an organization, as well as between different organizations and across the internet.

2. Multiprotocol Label Switching (MPLS)

MPLS is a networking technology that provides a way to forward data packets through a network based on short labels rather than long network addresses. It works by inserting a label into the packet header that identifies the path the packet should take through the network. Network nodes use labels to forward packets to the next node. It also eliminates the need for performing a complex lookup of the packet’s destination address each time it passes through a router.

Service providers widely use MPLS to build high-performance, efficient networks that can handle large volumes of traffic.

3. How MPLS Works?

MPLS works by assigning a label to each data packet that enters the network. Insert the label between the data link layer and network layer headers of the packet. It serves as an identifier for the path that the packet should take through the network. Network devices use this label to forward the packet along the correct path:


The basic steps in the MPLS forwarding process are:

  1. Label Assignment:  Based on the packet’s destination address, an MPLS network assigns a label to each packet as it enters the network. The packet header contains this designation
  2. Label Distribution: This process ensures that each router has the correct label information for every packet that passes through it. It allows the routers to quickly forward packets along the correct path without the need for complex lookups of packet headers
  3. Label Switching: As the packet travels across the system, each router uses the label to identify the following hop. After changing the label, the router forwards the packet to the following hop router
  4. Label Popping:  The final router takes off the label and sends the original packet to the intended device after the packet has arrived at its destination

4. Virtual Private LAN Service (VPLS)

Virtual Private LAN service enables the connection of multiple geographically dispersed sites by creating a virtualized LAN that spans across different locations. This allows devices at each site to communicate with each other as if they were connected to the same physical network switch

It enables the extension of a local area network (LAN) over a wide area network (WAN) infrastructure. VPLS creates a virtual LAN  that spans multiple geographically dispersed sites, allowing for seamless communication between devices as if they were all on the same physical LAN. Businesses with multiple locations typically use it to enable their employees to work as if they were all in the same office.

5. How VPLS Works?

In a Virtual Private LAN, Several key elements work together in the Service network to provide a seamless and efficient networking solution. These elements include hardware devices such as routers, switches, and firewalls, as well as software components. These elements enable communication and data transfer between different devices and systems, both within an organization and across the internet. Here are the main elements that make up a VPLS network:

  • Provider Edge (PE) routers: These are the routers located at the edge of the service provider’s network. They are responsible for receiving and forwarding customer traffic between different VPLS sites
  • Customer Edge (CE) routers: These are the routers located at the customer’s sites. They are responsible for connecting the customer’s LAN to the VPLS network
  • Pseudo-wire Emulation Edge-to-Edge (PWE3): This is the protocol used to encapsulate Ethernet frames and transport them over the service provider’s network
  • Virtual Forwarding Instance (VFI): This is the logical entity that represents the virtual LAN in the VPLS network. It is responsible for forwarding Ethernet frames between different VPLS sites
  • Service Distribution Points (SDPs): We design the VPLS network to connect multiple sites together and allow seamless forwarding of customer traffic from one VPLS site to another. To achieve this, we include several key points in the VPLS network where customer traffic is forwarded between sites, commonly referred to as VPLS edge devices

6. Differences Between MPLS and VPLS

Both MPLS and VPLS are types of Virtual Private Network (VPN) technologies but still, there are some key differences between the two.

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7. Factors to Consider When Choosing Between MPLS and VPLS

While choosing between MPLS and VPLS, it is important to consider network requirements, bandwidth requirements, and network security. If the network consists of multiple types of networks, then MPLS might be the better option. On the other hand, if the network primarily consists of Ethernet-based LANs, then VPLS might be a more suitable option.

MPLS supports high-bandwidth applications such as video conferencing and large data transfers. The underlying Ethernet network may limit VPLS by its bandwidth. This makes MPLS an ideal solution for organizations that require robust and efficient communication between sites with high bandwidth demands. However, VPLS is a more cost-effective and practical choice for businesses that prioritize extending their LAN architecture.

One of the major factors is Network Security, and both MPLS and VPLS offer a high level of security. MPLS provides secure connectivity between sites using encrypted labels, while VPLS uses a combination of MAC-in-MAC and Pseudo-wire Emulation Edge-to-Edge (PWE3) protocols to ensure data privacy.

8. Use Cases

Primarily MPLS connects multiple sites within their network, and VPLS extends Ethernet-based LANs over a wide area network. The specific networking scenarios for implementing both MPLS and VPLS can vary based on the network’s requirements. Here are some of them:

  • Providing secure connectivity for remote workers
  • Connecting data centers to support disaster recovery and business continuity
  • Supporting real-time applications such as video conferencing and voice over IP (VoIP)
  • Connecting multiple service provider networks to create a global network
  • Providing secure connectivity for cloud services

9. Conclusion

In summary, MPLS and VPLS are tools for connecting geographically dispersed sites, and each has its own strengths and weaknesses. Understanding the differences between MPLS and VPLS is essential for selecting the right solution for your organization’s needs.

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