The MAC addresses are used to specify both the destination and the source of each data packet.

IEEE 802. 3 is a working group and a collection of IEEE standards produced by the working group defining the physical layer and data link layer's media access control ( MAC ) of wired Ethernet.

As with any MAC, it may be used to simultaneously verify both the data integrity and the authenticity of a message.

However, this method suffers from a serious flaw: with most hash functions, it is easy to append data to the message without knowing the key and obtain another valid MAC (" length-extension attack ").

MAC protocol data unit or MPDU is a message ( Protocol data unit ) exchanged between MAC entities in a communication system based on the layered OSI model.

In systems where the MPDU may be larger than the MAC service data unit ( MSDU ), the MPDU may include multiple MSDUs as a result of packet aggregation.

* MAC protocol data unit

* MAC service data unit

For example, in order to perform digital filters fast enough, the MAC instruction in a typical digital signal processor ( DSP ) must be implemented using a kind of Harvard architecture that can fetch an instruction and two data words simultaneously, and it requires a single-cycle multiply – accumulate multiplier.

* interfaces with the data link layer's media access control ( MAC ) sublayer,

Another example of a data link layer which is split between LLC ( for flow and error control ) and MAC ( for multiple access ) is the ITU-T G. hn standard, which provides high-speed local area networking over existing home wiring ( power lines, phone lines and coaxial cables ).

In some networks, such as IEEE 802 local area networks, the data link layer is described in more detail with media access control ( MAC ) and logical link control ( LLC ) sublayers ; this means that the IEEE 802. 2 LLC protocol can be used with all of the IEEE 802 MAC layers, such as Ethernet, token ring, IEEE 802. 11, etc., as well as with some non-802 MAC layers such as FDDI.

The data link layer has two sublayers: logical link control ( LLC ) and media access control ( MAC ).

* The pseudorandom function splits the input data in half and processes each one with a different hashing algorithm ( MD5 and SHA-1 ), then XORs them together to create the MAC.

In the seven-layer OSI model of computer networking, media access control ( MAC ) data communication protocol is a sublayer of the data link layer, which itself is layer 2.

* The term network segment is sometimes used to refer to the portion of a computer network in which computers can access each other using a data link layer protocol ( e. g., in Ethernet, this would be the ability to send an Ethernet packet to others using their MAC addresses ).

This standard describes mainly the data link layer ( composed of the logical link control ( LLC ) sublayer and the media access control ( MAC ) sublayer ) and some aspects of the physical layer of the OSI reference model.

MAC layer defines protocols for routing, security and power saving and provides naturally data transfer to the upper layers.

Bcl-2 proteins are able to promote or inhibit apoptosis by direct action on MAC / MOMPP.

* static allocation: The DHCP server allocates an IP address based on a table with MAC address / IP address pairs, which are manually filled in ( perhaps by a network administrator ).

Concerning information processing, DARPA made great progress, initially through its support of the development of time-sharing ( all modern operating systems rely on concepts invented for the Multics system, developed by a cooperation among Bell Labs, General Electric and MIT, which DARPA supported by funding Project MAC at MIT with an initial two-million-dollar grant ).

The low-rate mesh is built on IEEE 802. 15. 4-2006 MAC, while the high rate mesh utilizes IEEE 802. 15. 3 / 3b MAC.

Beneath the LLC sublayer is the Media Access Control ( MAC ) sublayer, which is dependent on the particular medium being used ( Ethernet, token ring, FDDI, 802. 11, etc.

Interfaces can have addresses based on the MAC address of the machine ( the EUI-64 format ), but this is not a requirement.

Even when an address is not based on the MAC address though, the interface's address is ( contrary to IPv4 ) usually global instead of local, which makes it much easier to identify a single user through the IP address.

A Media Access Control address ( MAC address ) is a unique identifier assigned to network interfaces for communications on the physical network segment.

Queueing theory models have been developed on performance analysis and QoS for MAC layer protocols.

This function is referred to as layer 2 bridging, as the addresses it uses to forward the traffic are layer 2 addresses ( e. g. MAC addresses on Ethernet ).

Unfortunately in many networks waking on directed packet ( any packet with the adapter's MAC address or IP address ) or on link is likely to cause wakeup immediately after going to a low-power state.

Hellfire II's semi-active laser variants — AGM-114K high-explosive anti-tank ( HEAT ), AGM-114KII with external blast fragmentation sleeve, AGM-114M ( blast fragmentation ), and AGM-114N metal augmented charge ( MAC )— achieve pinpoint accuracy by homing in on a reflected laser beam aimed at the target.

However, by convention a subnet on broadcast MAC layer networks always has 64-bit host identifiers.

These rights and permissions are implemented differently in systems based on discretionary access control ( DAC ) and mandatory access control ( MAC ).

MAC controls read and write permissions based on a user's clearance level and additional labels.

To appreciate the innovative value of the DQDB MAC algorithm, it must be seen against the background of LAN protocols at that time, which were based on broadcast ( such as ethernet IEEE 802. 3 ) or a ring ( like token ring IEEE 802. 5 and FDDI ).

Later revisions allowed multiple addresses in addition to X. 121 addresses to be carried on the same DTE-DCE interface: Telex addressing ( F. 69 ), PSTN addressing ( E. 163 ), ISDN addressing ( E. 164 ), Internet Protocol addresses ( IANA ICP ), and local IEEE 802. 2 MAC addresses.

Carrier Sense Multiple Access ( CSMA ) is a probabilistic Media Access Control ( MAC ) protocol in which a node verifies the absence of other traffic before transmitting on a shared transmission medium, such as an electrical bus, or a band of the electromagnetic spectrum.

It originated at MIT's Project MAC ( from which it derived its prefix ) in the late 1960s and was based on Lisp 1. 5.

Mac Process ( formally MAC Equipment ) is also a large employer in the area, manufacturing bulk material handling and air filtration equipment.

On 18 February 1943, the Mediterranean Air Command ( MAC ) was established with Air Chief Marshal Sir Arthur Tedder in charge of all Allied air forces in the Mediterranean Theater of Operations ( MTO ).

Throughout these periods of World War II when air interdiction was practiced and developed, Tedder was always at the forefront as Air Commander-in-Chief of RAF Middle East Command, Mediterranean Air Command ( MAC ), Mediterranean Allied Air Forces, and as Gen. Dwight D. Eisenhower's Deputy Supreme Allied Commander for planning the air operations of the Normandy campaign.

At the time of Operation Husky, the Allied air forces in the North African and Mediterranean Theater of Operations ( MTO ) were organized into the Mediterranean Air Command ( MAC ) under Air Chief Marshal Sir Arthur Tedder.

For this mission, the unit provided a single commander for MAC airlift units in the Pacific theater ; command and control of theater-assigned airlift forces for Pacific Air Forces ; theater tactical airlift war planning and Pacific exercise planning ; and aerial ports in the Pacific area to support the air movement of personnel, cargo, equipment, patients, and mail.

It monitors the airspace around an aircraft for other aircraft equipped with a corresponding active transponder, independent of air traffic control, and warns pilots of the presence of other transponder-equipped aircraft which may present a threat of mid-air collision ( MAC ).

At the time of Operation Husky, the Allied air forces in the North African and Mediterranean Theaters were organized as the Mediterranean Air Command ( MAC ) under the command of Air Chief Marshal Sir Arthur Tedder of the Royal Air Force.

On 1 June 1992, Strategic Air Command ( SAC ) was inactivated and the 305th realigned to the newly established Air Mobility Command ( AMC ), merging former SAC air refueling aircraft with strategic and tactical theater airlift aircraft operated by the former Military Airlift Command ( MAC ), the latter also having been inactivated on the same date.

MAC filtering is effective only for small residential ( SOHO ) networks, since it provides protection only when the wireless device is " off the air ".

Any 802. 11 device " on the air " freely transmits its unencrypted MAC address in its 802. 11 headers, and it requires no special equipment or software to detect it.

In an organizational environment, where most wireless devices are " on the air " throughout the active working shift, MAC filtering provides only a false sense of security since it prevents only " casual " or unintended connections to the organizational infrastructure and does nothing to prevent a directed attack.