Types of MAC Address

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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