How does PIM build the IP multicast routing table to route traffic between a multicast source and one or more receivers?
How does PIM build the IP multicast routing table to route traffic between a multicast source and one or more receivers?
PIM (Protocol Independent Multicast) builds the IP multicast routing table by leveraging the unicast routing table and implementing Reverse Path Forwarding (RPF). The RPF process ensures that multicast traffic is forwarded through the network efficiently and prevents routing loops. The unicast routing table is used to determine the best path back to the multicast source, thereby aiding in the construction of the multicast distribution tree.
Answer is A "PIM also relies on the unicast routing tables to identify the path back to a multicast source. This routing method is known as reverse path forwarding (RPF). The unicast routing protocols create the unicast routing tables. With this information, PIM sets up the distribution tree for the multicast traffic.
The Correct Answer is A
Page 618 Study Guide: Each router in the network must calculate the tree independently based on the information it has received, whether by dynamic protocol updates (PIM), or by configuration. Using Reverse Path Forwarding (RPF), the router checks for loops and creates the Outgoing Interface List (OIL) from the best (sometimes called shortest) paths from the unicast routing table. For this reason, a source tree is also called a shortest path tree. [Aruba Networks]
The Correct Answer is A