Tag: MPLS

MPLS

Posted on by lechuck park

From Claude with some prompting
Let me explain this MPLS (Multiprotocol Label Switching) diagram:

  1. Left Section – Network Stack:
  • Application layer
  • TCP/UDP layer
  • IP layer
  • Ethernet layer
  1. Middle Section – MPLS Label Structure:
  • Label (20 bits): Used for routing
  • Experimental (3 bits): For QoS (Quality of Service) priority
  • Bottom of Stack (1 bit): Indicates if it’s the last label (Not Bottom: 0)
  • TTL (8 bits): Time to Live, prevents looping
  1. Right Section – MPLS Network Operation:
  • Label Edge Router (LER): Adds/removes labels at network boundaries
  • Label Switching Router (LSR): Performs label-based switching
  • Packets expire when TTL reaches 0
  • Routing based on priority using Experimental (QoS) bits

Operational Flow:

  1. Add Label Header: When packets enter MPLS network
  2. Routing by Label: Packet forwarding based on labels with Priority by Exp(QoS)
  3. Remove Label Header: When packets exit MPLS network

Key Benefits of MPLS:

  • Fast packet forwarding (label-based switching)
  • QoS support
  • Efficient traffic engineering
  • Support for multiple network protocols

The diagram shows how MPLS creates a more efficient and manageable network by using label-based forwarding instead of traditional IP routing. Labels can be stacked (Label Stack-able) for more complex routing scenarios, and the TTL field helps prevent infinite routing loops.