Junos MPLS and VPNs



In this course, you will learn about Multiprotocol Label Switching (MPLS) concepts such as control and forwarding plane, RSVP Traffic Engineering, LDP, Layer 3 VPNs, BGP Layer 2 VPNs, LDP Layer 2 Circuits, and virtual private LAN service (VPLS), carrier-of-carrier VPNs. This course also covers Junos operating system-specific implementations of Layer 2 control instances and active interface for VPLS and it is based on the Junos OS Release 12.3R2.5.

Through demonstrations and hands-on labs, you will gain experience in configuring and monitoring the Junos OS and in device operations.


Juniper Networks Certified Internet Specialist (JNCIS-SP)


Individuals responsible for configuring and monitoring devices running the Junos OS


  • Intermediate-level networking knowledge and an understanding of the Open Systems Interconnection (OSI) model and the TCP/IP protocol suite
  • Familiarity with the Protocol Independent Multicast-Sparse Mode (PIM-SM) protocol
  • Attend the following courses prior to attending this class:

Learning Objectives

What You'll Learn in Class:

  • Packet flow and handling through a MPLS label-switched path (LSP)
  • Configuration and verification of MPLS forwarding
  • Configure and troubleshoot RSVP-signaled and LDP-signaled LSPs
  • Path selection process of RSVP without the use of the Constrained Shortest Path First (CSPF) algorithm
  • Interior Gateway Protocol (IGP) extensions used to build the Traffic Engineering Database (TED)
  • CSPF algorithm and its path selection process
  • Administrative groups and how they can be used to influence path selection
  • Default traffic protection behavior of RSVP-Signaled LSPs
  • Use of primary and secondary LSPs
  • Operation and configuration of link and node protection and fast reroute
  • Features of provider-provisioned VPNs supported by the Junos OS
  • Roles of Provider (P) routers, Provider Edge (PE) routers, and Customer Edge (CE) routers
  • VPN-IPv4 address formats
  • Purpose of BGP extended communities and Route distinguishers
  • Steps necessary for proper operation of a PE to CE dynamic routing protocol
  • Configure a simple Layer 3 VPN using a dynamic CE-PE routing protocol
  • Various Layer 3 VPN class-of-service (CoS) mechanisms supported by the Junos OS
  • Purpose and features of a BGP Layer 2 VPN
  • BGP Layer 2 VPN scaling mechanisms and route reflection
  • Junos OS BGP Layer 2 VPN CoS support
  • Configure an LDP Layer 2 circuit
  • Configure circuit cross-connect (CCC) MPLS interface tunneling
  • Signaling process of VPLS
  • Learning and forwarding process of VPLS
  • Potential loops in a VPLS environment
  • The Junos OS support for carrier-of-carriers and Interprovider VPNs

1. Course Introduction

2. MPLS Fundamentals

  • MPLS Foundation
  • Terminology
  • MPLS Configuration
  • MPLS Packet Forwarding

3. Label Distribution Protocols

  • Label Distribution Protocols
  • RSVP
  • LDP

4. Constrained Shortest Path First

  • RSVP Behavior Without CSPF
  • CSPF Algorithm
  • CSPF Tie Breaking
  • Administrative Groups
  • Interarea Traffic Engineered LSPs

5. Traffic Protection and LSP Optimization

  • Default Traffic Protection Behavior
  • Primary and Secondary LSPs
  • Fast Reroute
  • Bypass LSPs
  • LSP Optimization

6. Fate Sharing

  • Junos OS Fate Sharing
  • SRLG
  • Extended Admin Groups

7. Miscellaneous MPLS Features

  • Routing Table Integration
  • Forwarding Adjacencies
  • Policy Control over LSP Selection
  • LSP Metrics
  • Automatic Bandwidth
  • TTL Handling
  • Explicit Null Configuration
  • MPLS Pings

8. VPN Review

  • Overview of VPNs
  • CPE-Based VPNs
  • Provider-Provisioned

9. Layer 3 VPNs

  • Layer 3 VPN Terminology
  • VPN-IPv4 Address Structure
  • Operational Characteristics

10. Basic Layer 3 VPN Configuration

  • Preliminary Steps
  • PE Router Configuration

11. Troubleshooting Layer 3 VPNs

  • A Layered Approach
  • The Routing-Instance Switch
  • PE-Based and CE-Based Traceroutes
  • Viewing VRF Tables and PE-PE Signaling Flow
  • Monitoring PE-CE Routing Protocols

12. Layer 3 VPN Scaling and Internet Access

  • Scaling Layer 3 VPNs
  • Public Internet Access Options

13. Layer 3 VPNs-Advanced Topics

  • Exchanging Routes Between VRF Tables
  • Hub-and-Spoke Topologies
  • Layer 3 VPN CoS Options
  • Layer 3 VPN and GRE Tunneling Integration
  • Layer 3 VPN and IPsec Integration

14. BGP Layer 2 VPNs

  • Overview of Layer 2 Provider-Provisioned VPNs
  • BGP Layer 2 VPN Operational Model: Control Plane
  • BGP Layer 2 VPN Operational Model: Data Plane
  • Preliminary BGP Layer 2 VPN Configuration
  • BGP Layer 2 Configuration
  • Monitoring and Troubleshooting BGP Layer 2 VPNs

15. Layer 2 VPN Scaling and CoS

  • Review of VPN Scaling Mechanisms
  • Layer 2 VPNs and CoS

16. LDP Layer 2 Circuits

  • LDP Layer 2 Circuit Operation
  • LDP Layer 2 Circuit Configuration
  • LDP Layer 2 Circuit Monitoring and Troubleshooting
  • Circuit Cross-Connect

17. Virtual Private LAN Services

  • Layer 2 MPLS VPNs Versus VPLS
  • BGP VPLS Control Plane
  • BGP VPLS Data Plane
  • Learning and Forwarding Process
  • Loops

18. VPLS Configuration

  • VPLS Configuration
  • VPLS Troubleshooting

19. Interprovider VPNs

  • Hierarchical VPN Models
  • Junos Support of Carrier-of-Carriers Model
  • Junos Support of Carrier-of-Carrier VPN Applications

20. Appendix A: Multicast VPNs

  • Multicast VPN Overview
  • Next-Generation MVPN Operation
  • Configuration
  • Monitoring