It operates between traditional data link layer (Layer 2) and network layer (Layer 3) protocols, and is used in both private networks and public networks. 

• Label-Based Routing: Unlike traditional IP routing, which uses network addresses to make forwarding decisions, MPLS routes traffic based on labels. These labels provide a way to attach additional information to each packet, making data forwarding decisions faster and more efficient.

• Efficiency and Speed: MPLS increases the speed and controls the flow of network traffic by establishing predetermined, highly efficient paths for data packets. This is particularly useful for bandwidth-intensive applications and services.

• Quality of Service (QoS): MPLS supports QoS, allowing for the prioritization of certain types of traffic, such as voice and video, which is crucial for ensuring reliable performance of latency-sensitive applications.

• Traffic Engineering: MPLS provides tools for traffic engineering, meaning it can direct network traffic to take certain paths based on current network conditions, bandwidth availability, and other criteria.

• VPN Creation: MPLS is widely used in building Virtual Private Networks (VPNs). It can segregate and keep traffic separate for different users over a shared network infrastructure, ensuring security and efficient use of resources.

MPLS plays a crucial role in modern network architecture, offering an efficient and flexible way to optimize the performance and management of network traffic for a variety of applications and services.