The all-stations broadcast MAC address is a special group MAC address of all 1’s If this bit is 1, the MAC address is a group MAC address that identifies one or more (or all) stations connected to the IEEE 802 network.

If the I/G address bit is 0, it indicates that the MAC address field is an individual MAC address. The I/G address bit is used to identify the destination MAC address as an individual MAC address or a group MAC address. The next-to-LSB of the first octet for the assignment is the universal/local (U/L) address bit.Īs waza-ari noted, Wireshark uses the alternative 'LG' notation for the U/L bit. the least significant bit (LSB) of the first octet is the individual/group (I/G) address bit. Here's a copy-paste from the 802 'Overview and Architecture' document, Chapter 8 (MAC addresses): These are available for free through the IEEE GET Program, but you must login with an IEEE account. So the vast majority of cases (except for broadcast messages) you will see both bits set to 0 (unicast and vendor assigned), as can be confirmed in your screenshot.Įthernet is defined by the IEEE 802 standards. Many drivers and cards however do not enforce this, and I do not know one application which really relies on this one. When you administratively change the MAC address of your device to another address, then you should set this bit to one. The LG or UL bit on the other hand distinguishes vendor assigned and administratively assigned MAC addresses. In other words, an IG bit of 0 indicates that this is a unicast MAC address, an IG bit of 1 indicates a multicast or broadcast address. The IG bit distinguishes whether the MAC address is an individual or group (hence IG) address. Both the LG bit (sometimes also referred to as UL bit) and the IG bit are located in the most significant byte of each MAC address, where the IG bit is the least significant bit in this byte and the LG bit is the second least significant bit in this byte.

Wireshark oui mac