Impact of Using 239.0.0.1 Multicast Group on Existing Multicast Design

D.

Multicast is a network protocol used to efficiently send data from one source to many receivers. Multicast traffic is sent to a multicast group, which is identified by a multicast IP address. When a host wants to receive data from a multicast group, it joins the group by sending an IGMP (Internet Group Management Protocol) message to the network.

In this scenario, the application team wants to use the multicast group address 239.0.0.1 to stream the video to users. This is a private multicast address that is reserved by the Internet Assigned Numbers Authority (IANA) for use within an organization or site, and it is not meant to be forwarded beyond the boundaries of the private network.

Now, let's examine each of the given options to understand the potential impact of using this multicast group address on the existing multicast design:

A. Because 239.0.0.1 is a private multicast range, a flood of PIM packets that have to be processed by the CPU and hosts will be sent by the routers in the network. PIM (Protocol Independent Multicast) is a multicast routing protocol used by routers to forward multicast traffic. When a host joins a multicast group, it sends an IGMP message to the router, which then sends a PIM message to the upstream router to join the multicast tree. If the routers in the network are configured to forward private multicast traffic, they will flood PIM messages for the 239.0.0.1 group to all ports in the network. This flood of PIM messages can cause high CPU usage on the routers and hosts, potentially impacting network performance.

B. Because 239.0.0.1 is a private multicast range, the rendezvous point has to send out constant group updates that will have to be processed by the CPU and hosts. A rendezvous point (RP) is a multicast router that is responsible for receiving multicast traffic from the multicast source and forwarding it to the multicast group members. When a multicast group is created, an RP is designated for the group. If the routers in the network are configured to forward private multicast traffic, the RP will have to send constant group updates for the 239.0.0.1 group, which can cause high CPU usage on the routers and hosts, potentially impacting network performance.

C. The multicast application sends too many packets into the network and the network infrastructure drops packets. This option does not specifically relate to the use of the 239.0.0.1 multicast group address, and it is not clear what is meant by "too many packets." However, if the multicast application is sending an excessive amount of traffic, it can cause network congestion and packet loss.

D. The 239.0.0.1 group address maps to a system MAC address, and all multicast traffic will have to be sent to the CPU and flooded out all ports. Multicast traffic is sent to a multicast MAC address, which is derived from the multicast IP address. For the 239.0.0.1 multicast group address, the corresponding MAC address is 01-00-5E-00-00-01. If the routers in the network are not configured to forward private multicast traffic, they will send all multicast traffic to the CPU and flood it out to all ports, which can cause high CPU usage on the routers and hosts, potentially impacting network performance.

In summary, using the 239.0.0.1 multicast group address for video streaming can potentially impact the existing multicast design if the routers in the network are configured to forward private multicast traffic. This can cause high CPU usage on the routers and hosts, potentially impacting network performance. It is recommended to use multicast group addresses that are globally routable and not reserved for private use within an organization or site.