MAC (Media Access Control) addresses can be classified into several types based on their usage, assignment method, and uniqueness. Here are the main types of MAC addresses:
1. Unicast MAC Address
Definition: A unicast MAC address is assigned to a single network interface card (NIC) and is used for one-to-one communication.
Example: 00:1A:2B:3C:4D:5E
Usage: When a frame is sent to a unicast MAC address, it is intended for a specific device on the network.
2. Multicast MAC Address
Definition: A multicast MAC address allows a single frame to be delivered to multiple devices on the network.
Range: Multicast MAC addresses start with an OUI that signifies a multicast address. The first octet of a multicast address typically begins with 01.
Example: 01:00:5E:00:00:FB (used for IPv4 multicast)
Usage: Used in applications like streaming media, where data is sent to multiple devices simultaneously.
3. Broadcast MAC Address
Definition: The broadcast MAC address is used to send frames to all devices on the same local network.
Address: FF:FF:FF:FF:FF:FF
Usage: Used in scenarios where a message needs to be sent to every device on the network, such as ARP (Address Resolution Protocol) requests.
4. Locally Administered MAC Address (LAA)
Definition: A locally administered MAC address is one that has been manually assigned by a network administrator, overriding the default factory-assigned address.
Indicator: The second least significant bit of the first octet is set to 1 to indicate a locally administered address.
Usage: Used when there is a need to reassign MAC addresses for organizational purposes or network management.
5. Universally Administered MAC Address (UAA)
Definition: A universally administered MAC address is assigned by the NIC manufacturer and is intended to be unique across all devices globally.
Indicator: The second least significant bit of the first octet is set to 0.
Usage: These are the most common types of MAC addresses used in devices. For example, 00:1A:2B:3C:4D:5E where 00:1A:2B is the OUI identifying the manufacturer.
6. Virtual MAC Address
Definition: A virtual MAC address is used in scenarios involving virtual machines (VMs) or network devices configured for high availability.
Usage: Used by virtual routers, virtual machines, and in protocols such as VRRP (Virtual Router Redundancy Protocol) and HSRP (Hot Standby Router Protocol).
7. Burned-In Address (BIA)
Definition: A burned-in address is the MAC address programmed into the firmware of the NIC during manufacturing.
Usage: Typically, this is the default MAC address used by the network device unless it is overridden by a locally administered address.
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