What is MPLS?
MPLS (Multiprotocol Label Switching) is a method of directing traffic in networks using short labels instead of traditional IP routing. It is used in backbone and enterprise networks to ensure fast and reliable data transmission.
How Does MPLS Work?
Instead of analyzing IP headers, MPLS routers read the label in the packet and forward it along a predefined path (Label Switched Path — LSP).
Main Components:
- Label Edge Router (LER) — assigns and removes labels
- Label Switch Router (LSR) — forwards packets within the MPLS domain
- Label — a numeric identifier that replaces the IP address during forwarding
Advantages of MPLS
- Fast forwarding without deep IP header inspection
- Support for VPNs (L3VPN, L2VPN)
- Quality of Service (QoS)
- Traffic isolation and high reliability
Example of MPLS in a Provider Network
| Customer Network | Ingress LER | Backbone LSR | Egress LER |
|---|---|---|---|
| 10.1.0.0/24 | PE1 | P1 → P2 → P3 | PE2 |
Each node uses a label instead of an IP route for fast packet forwarding.
FAQ
Does MPLS replace IP?
No, IP remains in use, but packet forwarding is based on labels.
Is MPLS the same as a VPN?
No. MPLS is a transport mechanism. VPN is a service that MPLS can support (e.g., MPLS L3VPN).
Why is MPLS better than regular routing?
Faster forwarding, more flexible traffic management, and lower CPU load.
Conclusion
MPLS is a core technology in telecom infrastructure, enabling stable and manageable routing. It is especially relevant for building secure and resilient enterprise VPNs.
