Cover

Table of Content

  1.  Understanding MPLS (Multi Protocol Label Switching)
  2. Introduction to MPLS and BGP-Free Core
  3. MPLS (Multi Protocol Label Switching)
  4. MPLS Configuration:
  5. MPLS Labels and Devices:
  6. MPLS LDP (Label Distribution Protocol):
  7. LDP Configuration:
  8. MPLS-LDP Label Filtering
  9. Configuration of VRF Lite in Cisco Router
  10. MPLS Layer 3 VPN Explained
  11. MPLS Layer 3 VPN Configuration
  12. MPLS Layer 3-VPN BGP: Allow-AS-In
  13. MPLS Layer 3 VPN BGP AS Override

 

 

This eBook is based on Multiprotocol Labeling and Switching that has been collected from different sources and people. For more information about this ebook. Kindly write to poonam775304@gmail.com. I will happy to help you.

Copyright 2023 by Poonam Devi

This eBook is a guide and serves as a first guide. This book has been written on the advice of many experts and sources who have good command over MPLS, network an programming. They are listed at the end of this book.
All images used in this book are taken from the LAB which is created by experts. All rights reserved, including the right to reproduce this book or portions thereof in any form whatsoever. For any query reach out to the author through email.

Understanding MPLS (Multi Protocol Label Switching)

Course Overview: Explore the world of MPLS (Multi Protocol Label Switching) in this comprehensive course. MPLS is a revolutionary networking mechanism that employs labels instead of traditional routing techniques. Commonly found in service provider networks, MPLS can transport a wide range of data formats, including IP, IPv6, Ethernet, frame-relay, and PPP. Additionally, MPLS VPN is a widely adopted method for creating secure virtual private networks within MPLS provider networks.

Course Highlights: Throughout this course, you will gain knowledge in the following areas:

  1. The Purpose of MPLS: Understand the reasons behind the adoption of MPLS in networking.

  2. MPLS Fundamentals: Dive into the fundamentals of MPLS, including its functioning and key concepts.

  3. Label-Based Forwarding: Explore how labels are utilized to direct traffic within MPLS networks.

  4. MPLS VPN Configuration: Learn to configure various MPLS VPN Layer 3 PE-CE scenarios for enhanced network security.

  5. Protocol Tunneling: Discover the techniques for tunneling protocols like Ethernet and frame-relay over MPLS VPN networks.

  6. Comprehensive Learning: Delve into various other topics and aspects of MPLS.

Requirements: To make the most of this course, participants should have a solid understanding of the following concepts:

  • Interior Gateway Protocols (IGPs) such as RIP, OSPF, and EIGRP.

  • Tunneling techniques, including GRE (Generic Routing Encapsulation).

  • Border Gateway Protocol (BGP).

Join us on this educational journey to master MPLS and its practical applications in modern networking environments.

Introduction to MPLS and BGP-Free Core

Introduction: In this introductory lesson, we will explore the fundamentals of MPLS (Multi Protocol Label Switching) and why it is essential in modern networking. We'll address two key questions: What is MPLS, and why do we need it? To fully grasp MPLS, it's essential to have a solid understanding of topics such as IGPs (Interior Gateway Protocols), tunneling (specifically GRE), CEF (Cisco Express Forwarding), and BGP (Border Gateway Protocol).

Why do we need MPLS? To illustrate the need for MPLS, consider an Internet Service Provider (ISP) with two customers, labeled "A" and "B." These customers rely on the ISP for site-to-site connectivity. In the traditional approach, the ISP employs eBGP (external BGP) between the CE (Customer Edge) and PE (Provider Edge) routers to exchange routing information, requiring internal (P) routers to run iBGP (internal BGP) or remain unaware of packet forwarding destinations.

This approach results in several challenges, notably the need for all internal P routers to maintain iBGP peerings and perform extensive routing table lookups due to a full internet routing table with over 500,000 prefixes.

MPLS offers an elegant solution to these challenges. By establishing GRE tunnels between the PE routers, the ISP can create a BGP-free core network. In this configuration, BGP is only required at two specific points:

  1. Between the CE and PE routers (eBGP).

  2. Between the two PE routers (iBGP).

This approach significantly simplifies the ISP's core network while maintaining the desired connectivity between customer sites.

Tunnel between PE routers: To implement this solution, we use GRE tunnels between the PE routers. Here's a high-level overview of the configuration steps:

  1. Configure OSPF on all ISP routers to enable PE1 and PE2 to reach each other.

  2. Establish eBGP sessions between the CE routers and PE routers.

  3. Create GRE tunnels between PE1 and PE2, using their loopback interfaces as source and destination.

  4. Configure iBGP between the two PE routers to establish a peering over the GRE tunnel.

With these configurations in place, the GRE tunnel facilitates communication between PE1 and PE2, eliminating the need for iBGP on the internal P routers.

Verification: A traceroute from CE1 to CE2 confirms the success of the configuration, demonstrating that the ISP now operates with a BGP-free core, achieving efficient and simplified routing.

In summary, MPLS and GRE tunneling offer a powerful solution for service providers to streamline their networks, reduce the complexity of internal routing, and maintain seamless connectivity for their customers.

Imprint

Publisher: BookRix GmbH & Co. KG

Text: Poonam Devi
Images: Poonam Devi
Cover: Lokesh Pathak
Editing: Devesh Patel
Proofreading: Rishabh Jain
Translation: Richa Shukla
Layout: Poonam Devi
Publication Date: 10-08-2023
ISBN: 978-3-7554-5541-7

All Rights Reserved

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