IP MULTICAST ROUTING Part -3: Use of multicast routing.

By Ummed Singh

IP multicast routing is a technique used in computer networks to efficiently deliver data packets from a single sender to multiple recipients. It is specifically designed for applications where data needs to be distributed simultaneously to a group of interested receivers. In traditional unicast communication, a sender sends packets to individual receivers using their unique IP addresses. This creates a point-to-point connection between the sender and each receiver, resulting in duplicate transmissions if multiple receivers are interested in the same data. Unicast is inefficient for one-to-many or many-to-many communication scenarios. Multicast routing, on the other hand, allows a sender to transmit a single copy of a packet, and network routers replicate and forward it to all interested receivers. This saves network bandwidth and processing resources, as the data is distributed only once. Multicast routing uses special IP multicast addresses, typically in the range of 224.0.0.0 to 239.255.255.255, to identify multicast groups. To enable IP multicast routing, routers in the network need to support multicast routing protocols such as Protocol Independent Multicast (PIM). These protocols enable routers to exchange information about multicast groups and determine the optimal path for forwarding multicast traffic. Routers maintain multicast routing tables that specify the outgoing interfaces and next-hop routers for forwarding multicast packets. When a sender wants to send data to a multicast group, it encapsulates the data in a multicast packet and sets the appropriate multicast IP destination address. The routers along the path use the multicast routing tables to determine how to forward the packet to all interested receivers. Receivers interested in receiving multicast data join the multicast group by sending a membership request to the nearest router. The router adds the receiver to the multicast distribution tree, and subsequent multicast packets are forwarded.

• Language: English
• Publisher: BookRix
• Release date: Jul 23, 2023
• ISBN: 9783755447504

Book preview

Table of content

What is Multicast Routing?

Routing protocols of Multicast

Dense Mode:

What is Multicast PIM Dense Mode?

Reverse Path Forwarding (RPF)

Sparse Mode:

Scoping in Multicast

TTL Scoping

Administrative Scoping

PIM Dense Neighbors:

Prune Message for PIM Dense:

PIM Graft Message:

What is Multicast PIM Sparse Mode?

RP Discovery Protocols

PIM Sparse Mode

PIM Sparse Neighbors

Rendezvous Point (RP)

PIM Register

Joining the RPT (Root Path Tree)

What is Multicast PIM Sparse-Dense Mode?

This eBook is based on IP MULTICAST ROUTING that has been collected from different sources and people. For more information about this ebook. Kindly write to [e-mail]. I will happy to help you.

Copyright 2023 by Ummed Singh

This eBook is a guide and serves as a next part of first & second guides. Previous Parts IP MULTICAST ROUTING Part-1 & 2 have already been published. In addition, please get expert advice or you can write to [e-mail] for any query, we will be happy to help you. This book has been written on the advice of many experts and sources who have good command over Networking and routing. 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.

What is Multicast Routing?

The primary purpose of a router is to efficiently direct packets to their intended destinations. When the router receives an IP packet, it analyzes the destination address and consults its routing table to determine the appropriate next hop for forwarding the packet. To accomplish this, various routing protocols are employed, enabling the router to learn about different networks and populate its routing table accordingly.

Let's use an analogy to explain this process:

Imagine a router as a diligent mail carrier whose job is to deliver letters to specific addresses. Each letter (IP packet) has a destination address written on it. The router looks at the address on the letter and checks its delivery instructions stored in the routing table. For unicast traffic (regular one-to-one communication), the router follows the standard delivery process. Suppose Router R1 wants to send a letter to Destination 2.2.2.2. It consults its routing table and finds an entry for the path to 2.2.2.2, indicating that it should send the letter to the next hop, Router R2 (identified by the address 192.168.12.2). By