MPLS is faster than traditional IP routing primarily because it simplifies the decision-making process for data packets as they traverse the network.
Unlike traditional IP routing, which necessitates individual routing decisions at every single device (hop) along the path, MPLS makes routing decisions only once, at the network entry point. This fundamental difference is the key to MPLS's speed advantage.
Here's a breakdown of why this single decision point leads to faster performance:
- Reduced Processing Time per Hop: In traditional IP routing, each router must examine the destination IP address of a packet, look up the next hop in its routing table, and potentially perform complex calculations. This process adds latency at every step.
- Streamlined Forwarding: MPLS assigns a short label to each packet at the network edge (the entry point). Subsequent routers within the MPLS network simply use this label to forward the packet quickly along a pre-determined path (known as a Label Switched Path or LSP) without needing to re-examine the IP header or perform extensive lookups at each hop.
- Efficient Path Following: Since the path is decided upfront and marked by a label, data simply follows this established path. This bypasses the need for per-packet, per-hop routing decisions, significantly reducing the time it takes for data to travel through the network.
Ultimately, by eliminating the need for repetitive routing lookups at every hop, MPLS dramatically reduces the processing overhead for each packet within the core network. This efficiency reduces the amount of time it takes for data to travel through the network, leading to a fast and reliable service, as stated in the reference.
While modern IP routing hardware has become very fast, the architectural difference of deciding the path only once at the edge and then simply label-switching through the core provides a fundamental efficiency gain for MPLS, especially in high-traffic or time-sensitive environments.
