MPLS vs. VPLS

Attribute	MPLS	VPLS
Definition	Multiprotocol Label Switching	Virtual Private LAN Service
Network Type	Wide Area Network (WAN)	Local Area Network (LAN)
Layer	Layer 2	Layer 2
Protocol	Uses labels to forward packets	Uses MAC addresses to forward packets
Scalability	Highly scalable	Scalable
Topology	Supports various topologies	Supports point-to-multipoint topology
Service Type	Supports multiple services (e.g., VPN, QoS)	Primarily used for VPN services
Control Plane	Uses Label Distribution Protocol (LDP)	Uses Border Gateway Protocol (BGP)
Forwarding Plane	Uses Label Switching Routers (LSRs)	Uses Provider Edge (PE) routers

Introduction

When it comes to wide area networking (WAN), there are several technologies available to connect geographically dispersed locations. Two popular options are Multiprotocol Label Switching (MPLS) and Virtual Private LAN Service (VPLS). While both serve the purpose of connecting multiple sites, they differ in their underlying architecture and functionality. In this article, we will explore the attributes of MPLS and VPLS, highlighting their key features, advantages, and use cases.

MPLS: Multiprotocol Label Switching

MPLS is a protocol-agnostic technology that operates at the network layer of the OSI model. It uses labels to forward packets efficiently across a network, creating virtual paths or circuits. These labels are added to the packets at the ingress router and removed at the egress router, allowing for fast and deterministic forwarding. MPLS networks are typically built using a combination of Label Edge Routers (LERs) and Label Switch Routers (LSRs).

One of the key advantages of MPLS is its ability to provide traffic engineering capabilities. By assigning different labels to packets, MPLS can prioritize certain types of traffic, ensuring optimal performance for critical applications. MPLS also offers built-in Quality of Service (QoS) mechanisms, allowing for the prioritization and differentiation of traffic based on specific requirements.

Another important attribute of MPLS is its support for multiple service types. It can be used to establish Layer 2 Virtual Private Networks (VPNs), Layer 3 VPNs, and Traffic Engineering tunnels. MPLS VPNs provide secure and isolated connectivity between different sites, while Traffic Engineering tunnels enable efficient utilization of network resources.

MPLS networks are widely used in enterprise environments, particularly for connecting branch offices to a central location. They offer scalability, reliability, and the ability to handle large amounts of traffic. However, MPLS can be expensive, as it often requires dedicated hardware and service provider involvement.

VPLS: Virtual Private LAN Service

VPLS, on the other hand, is a Layer 2 technology that extends the functionality of a local area network (LAN) over a wide area network. It allows multiple sites to appear as if they are connected to the same LAN, regardless of their physical location. VPLS achieves this by creating a virtual bridge that connects the LAN segments of different sites.

One of the key advantages of VPLS is its simplicity. It provides a transparent and seamless extension of the LAN, allowing for plug-and-play connectivity between sites. VPLS networks are typically built using Ethernet switches, which are widely available and cost-effective. This makes VPLS an attractive option for organizations looking for a straightforward and affordable solution.

VPLS also offers scalability, as it can support a large number of sites and VLANs. It provides a flexible and dynamic environment, allowing for the addition or removal of sites without disrupting the overall network. Additionally, VPLS networks can be easily integrated with existing LAN infrastructure, making it a suitable choice for organizations with established Ethernet-based networks.

However, it is important to note that VPLS may not provide the same level of traffic engineering and QoS capabilities as MPLS. While VPLS can prioritize traffic within the LAN segment, it may not have the same granular control over traffic across the entire network. This can be a limitation for organizations with strict performance requirements or the need for differentiated services.

Comparison and Use Cases

When comparing MPLS and VPLS, it is essential to consider the specific requirements and priorities of the organization. MPLS is often favored for its traffic engineering capabilities, QoS support, and ability to handle large-scale deployments. It is commonly used by enterprises that require secure and reliable connectivity between multiple sites, particularly when dealing with sensitive data or critical applications.

VPLS, on the other hand, is a suitable choice for organizations that prioritize simplicity, affordability, and seamless LAN extension. It is commonly used by small to medium-sized businesses that need to connect multiple offices or remote workers to a central location. VPLS can also be an excellent option for organizations with existing Ethernet-based infrastructure, as it allows for easy integration and expansion.

It is worth noting that both MPLS and VPLS can coexist within a network, serving different purposes based on specific requirements. For example, an organization may choose to use MPLS for its critical sites that require traffic engineering and QoS, while using VPLS for less critical sites that prioritize simplicity and cost-effectiveness.

Conclusion

In conclusion, MPLS and VPLS are two distinct technologies that offer different attributes and advantages. MPLS provides traffic engineering capabilities, QoS support, and the ability to establish secure VPNs and Traffic Engineering tunnels. It is commonly used by enterprises that require reliable and scalable connectivity between multiple sites. On the other hand, VPLS offers simplicity, affordability, and seamless LAN extension. It is often chosen by small to medium-sized businesses and organizations with existing Ethernet-based infrastructure.

Ultimately, the choice between MPLS and VPLS depends on the specific needs and priorities of the organization. By understanding the attributes of each technology, organizations can make informed decisions to meet their networking requirements effectively.