Technology - IP Techniques 5 - MPLS Architecture

Synopsis

Multiprotocol Label Switching (MPLS) is the widely used IETF protocol for efficient forwarding of IP packets, including with QoS (Quality of Service). This report discusses the basic principles of MPLS, including the structure of MPLS headers, Forwarding Equivalence Class (FEC), transit router operation, ingress and egress processing, Traffic Engineering, Penultimate Hop Popping and stacked MPLS labels.

Table of Contents

• 1. Synopsis
• 2. Introduction
  • 2.1 More efficient handling of IP packets
  • 2.2 Generalised MPLS - GMPLS
• 3. Carrying MPLS labelled packets
  • 3.1 Types of packets which may be labelled
  • 3.2 Connection oriented Label Switched Paths (LSPs)
  • 3.3 Stacked MPLS labels
  • 3.4 Label Switched Path as an alternative to IP routing
    • 3.4.1 IP routing is costly
• 4. MPLS terminology
• 5. MPLS header structure
• 6. Label Switched Path in operation
  • 6.1 Classification and labelling at the ingress router
  • 6.2 Simple progressing at transit routers
  • 6.3 Egress processing
  • 6.4 Penultimate hop popping
  • 6.5 Adding another MPLS label
  • 6.6 QoS bits in the MPLS header
  • 6.7 Key benefits of MPLS forwarding
• 7. Forwarding Equivalent Class (FEC)
  • 7.1 QoS and CoS attributes built into the LSP
  • 7.2 Traffic engineering
• 8. Related reports