While inspecting packets in the network, a network administrator discovers a frame with the destination MAC address of 01-00-5E-A0-B1-C3. What can the administrator determine from this?

Ethernet MAC addresses are classified based on the least significant bit (LSB) of the first octet. If the LSB is 1, the address is a multicast (or group) address. The given MAC address is 01-00-5E-A0-B1-C3. The first octet is 0x01 (binary 00000001), where the LSB is 1, definitively identifying it as a multicast address. Furthermore, the prefix 01-00-5E is specifically reserved by IANA for mapping IPv4 multicast addresses to Layer 2 MAC addresses, confirming its multicast nature.

A. The MAC address is correctly formatted and falls within the standard range for IP multicast; it is not incorrect.
C. The broadcast MAC address is a specific type of multicast address where all bits are set to 1 (FF-FF-FF-FF-FF-FF).
D. A unicast MAC address must have the least significant bit of its first octet set to 0.

- Huawei HedEx Documentation, VRP V800R012C10 Product Documentation, "IP Multicast Principles - Layer 2 Multicast". This section explains the mapping of Layer 3 multicast addresses to Layer 2 multicast MAC addresses, noting the 01-00-5E prefix.

- IETF RFC 1112, "Host Extensions for IP Multicasting," Section 6.4. This document specifies that IPv4 multicast groups are mapped to the block of Ethernet multicast addresses from 01-00-5E-00-00-00 to 01-00-5E-7F-FF-FF.