MPLS (Multiprotocol Label Switching) architecture is a method used in telecommunications networks to efficiently direct data packets through a network. It operates between Layer 2 (data link layer) and Layer 3 (network layer) of the OSI model, enabling faster packet forwarding by using labels to designate paths instead of traditional IP routing tables. MPLS architecture includes routers and switches equipped to handle MPLS packets, along with label distribution protocols (LDP or RSVP-TE) to establish label-switched paths (LSPs) across the network. MPLS allows for traffic engineering, quality of service (QoS), and virtual private network (VPN) capabilities.
The basic MPLS topology typically involves a core network with MPLS-enabled routers interconnected in a mesh or hierarchical fashion. MPLS operates in a label-switched domain (LSD), where routers use labels to forward packets based on pre-established paths known as label-switched paths (LSPs). At the edge of the MPLS network, routers interface with customer networks or other networks using traditional IP routing or other protocols, ensuring seamless integration and efficient traffic handling within the MPLS infrastructure.
The primary difference between IP and MPLS lies in their fundamental approaches to packet forwarding and routing. IP (Internet Protocol) is a routed protocol that forwards packets based on destination IP addresses. Each router in an IP network makes forwarding decisions based on IP routing tables, which store information about the best paths to reach destination networks. In contrast, MPLS uses labels to forward packets through a network. Routers in an MPLS network use labels to determine the next hop and path for each packet, enabling faster forwarding and more efficient traffic management compared to traditional IP routing. MPLS can also provide traffic engineering, QoS, and VPN capabilities that are more flexible and scalable than IP routing alone.