Figure 80. Multicast with ECMPImplementation InformationBecause protocol control traffic in Dell Networking OS is redirected using the MAC address, and multicastcontrol traffic and multicast data traffic might map to the same MAC address, Dell Networking OS mightforward data traffic with certain MAC addresses to the CPU in addition to control traffic.As the upper5 bits of an IP Multicast address are dropped in the translation, 32 different multicast groupIDs all map to the same Ethernet address. For example, 224.0.0.5 is a known IP address for open shortestpath first (OSPF) that maps to the multicast MAC address 01:00:5e:00:00:05. However, 225.0.0.5,226.0.0.5, and so on, map to the same multicast MAC address. The Layer 2 forwarding information base(FIB) alone cannot differentiate multicast control traffic multicast data traffic with the same address, so ifyou use IP address 225.0.0.5 for data traffic, both the multicast data and OSPF control traffic match thesame entry and are forwarded to the CPU. Therefore, do not use well-known protocol multicastaddresses for data transmission, such as the following.Protocol Ethernet AddressOSPF 01:00:5e:00:00:0501:00:5e:00:00:06RIP 01:00:5e:00:00:09NTP 01:00:5e:00:01:01VRRP 01:00:5e:00:00:12534 Multicast Features
