Data link layer computer networks questions and answers. The mac layer is responsible for moving data packets to and from one network interface card nic to another across a shared channel. This sublayer communicates directly with the physical layer. There are 3 questions 24, 25, 26 were updated in 11 march, 2018. The mac sublayer and the logical link control llc sublayer together make up the data link layer. Download citation the medium access control sublayer the authors begin by giving a brief overview of the physical layer, the data link layer, the network. Mac sublayer media access control mac sublayer who goes next on a shared medium example.
Answer and provide a brief explanation to the following questions. Mac is responsible for the transmission of data packets to and from the networkinterface card, and to and from another remotely shared channel. Logical link control sublayer and media access control sublayer. Media access control an overview sciencedirect topics. Sometimes this refers to the sublayer that determines who is allowed to access the media at any one time usually csmacd.
Second layer of the osi reference model data link layer or the ieee 802 reference model which divides data link layer into logical link control and medium access control layer. In layer 2 of a network, the media access control mac sublayer provides addressing and channel access control mechanisms that enable several terminals or network nodes to communicate in a network. There are two different methods of channel allocations. Definition of media access control in the dictionary. Text andor other creative content from this version of talk. The channel allocation problem the mac medium access control sublayer is between the physical layer and the data link layer. Unfortunately, a systems programmer would never know. Which two statements describe features or functions of the.
As its name implies, it controls access to the media. The mac sublayer provides addressing and channel access control mechanisms that make it possible for several terminals or network nodes to communicate within a multiple access network that. At the medium access mac sublayer, frames consist of the following. Jul 09, 2012 media access control mac is a sublayer of the data link layer dll in the sevenlayer osi network reference model. In the sevenlayer osi model of computer networking, media access control mac data communication protocol is a sublayer of the data link layer layer 2. Csmaca wireless medium access control protocol duration.
Outline wireless lan technology medium access control for wireless ieee 802. The media access control mac sublayer and the logical link control llc sublayer. Media access control is responsible for the placement of frames on the media and the removal of frames from the media. The mac is the physical address of the computer and anything that connects to the network has its own unique mac. The logical link control llc sublayer of the data link layer manages communications between devices over a single link of a network. The network access layer contains two sublayers, the media access control mac sublayer and the physical sublayer. Solved examples with detailed answer description, explanation are given and it would be easy to understand. Transport control sublayer and media access control sublayer. Media access control mac definition media access control mac and logical link control llc are the sublayers of the data link layer layer 2 in osi reference model.
Which layer contains the media access control mac address. After reading the stuff presented here the reader will be able to. The underlying logical topology of ethernet is a multi access bus. If collision detected, transmit 32bit jamming sequence. The llc sub layer in turn receives services from its lower media access control sublevel in the medium. Apr, 2016 mac layer is also known as media access layer. As it is evident from the name itself that for the data link layer, the mac layer serves the purpose of managing the media access to different. In ieee 802 lanman standards, the medium access control mac, also called media access control sublayer is the layer that controls the hardware responsible for interaction with the wired, optical or wireless transmission medium. The media access control mac sublayer determines the physical addressing of the hosts for communicating with. There is no scheduled time for a stations to transmit.
Which statement describes the media access control methods that are used by the networks in the exhibit. The mac sublayer the medium access control mac sublayer is. The media access control sublayer of ethernet specifies the mac addresses of network. No software changes or downloading routing tables or parameters to it are needed. Random access protocols it is also called contention method.
Clause 1 through clause 140 and annex 5a through annex 6d are added to ieee std 802. The lowlevel protocol standards defined by ieee project 802 include 802. Media access control mac addresses are talked about in various sections on the site, such as the osilayer 2, multicast, broadcast and unicast. The pdf of this standard is available at no cost to you compliments of the ieee. The mac service provided by all ieee 802r macs along with the internal sublayer service iss that is provided by ieee 802 macs to the relay function of a media access control mac bridge are defined in this standard. The former pages history now serves to provide attribution for that content in the latter page, and it must not be deleted so long as the latter page exists. Pdf analysis of medium access control protocols for home. The media access control sublayer of ethernet specifies the mac addresses of network interfaces, the frame format, and the mac protocol for sharing the cable. Above the phy is the media access control mac sublayer of the data link layer. The network layer is supported by the sapsservice access points provided by the llc sublevel. When retrieving a spreadsheet from a busy file server b. The media access control layer is one of two sublayers that make up the data link layer of the osi model. It allows the receiver to detect the start of a frame. A media access control address mac address, also called physical address, is a unique identifier assigned to network interfaces for communications on the physical network segment.
Network access layer the lowest layer of the tcpip protocol stack is the network access layer. The mac sublayer provides addressing and channel access control mechanisms that make it possible for several terminals or network nodes to communicate within a multiple access network that incorporates a shared medium, e. The mac sublayer is especially important in lans, nearly all of which use. The common industrial protocol cip is an application. Information and translations of media access control in the most comprehensive dictionary definitions resource on the web. Medium access protocols ethernet collisionfree protocols wireless ethernet wlan local area network aloha slotted aloha csma three scenarios medium access protocols can be classi ed into three broad types depending on the nature of the medium and the ability to sense detect possible collisions stations contending for the medium cannot sense. The mac sublayer is also responsible for adding a header and a trailer to the network layer protocol data unit pdu. Jan 20, 2016 a media access control address mac address, also called physical address, is a unique identifier assigned to network interfaces for communications on the physical network segment. C service rate of the channel in frames second 10 frames sec. Data link layer computer networks questions and answers this is the networking questions and answers section on data link layer with explanation for various interview, competitive examination and entrance test. Media access control oldversion was copied or moved into media access control with this edit. Jul 06, 2018 the network layer is supported by the sapsservice access points provided by the llc sublevel. The portion of physical layer that interfaces with the media. There are generally two forms of media access control.
The station can make a decision on whether or not to send data. Medium access control sublayer the assumption in the datalink layer is one of direct, pointtopoint connections. This decision depends on the state of the channel, i. The former pages talk page can be accessed at talk. The llc sub layer in turn receives services from its lower media access control. The mac media access control sublayer is responsible for the placement and retrieval of frames on and off the media.
Ccna certificationdata link layer wikibooks, open books. Protocol standards defined by ieee project 802 and fddi. These standards differ at the physical layer and media access control sublayer, but are compatible at the logical link control sublayer. The medium access control mac sublayer is the bottom half of the datalink layer. Physical layer computer networks questions and answers. Precise realtime software access and control of wired networks ki suh lee, han wang, hakim weatherspoon. Media access control mac is a sublayer of the data link layer dll in the sevenlayer osi network reference model. The other sublayer level in the dlc layer is the logical link control sublayer. Other times it refers to a frame structure with mac addresses inside.
Logical link control sublayer and media access control sublayer b. Oct 20, 2008 functions of mac sublayer computer networks. Know different types of channel allocation this tutorial deals with the channel access problems like who should be the. The hardware that implements the mac is referred to as a media access controller. Ethernet hosts can sense if medium in use algorithm for sending data. The mac address is used by the media access control sublayer of the datalink layer dlc of telecommunication protocols. Example csmacd ocarrier sense multiple access with collision detection.
Under what conditions is media access control unimportant. The mac address of an ethernet interface card is a 48bit string set by the manufacturer that is unique to that card. Understand about the channel allocation problem iii. File sharing because nodes both download and upload files. Usually the pdf of frame generation is taken to be a poisson distribution with. Aug 05, 2015 in the sevenlayer osi model of computer networking, media access control mac data communication protocol is a sublayer of the data link layer layer 2. Precise realtime software access and control of wired. This is the networking questions and answers section on physical layer with explanation for various interview, competitive examination and entrance test. The mac sublayer acts as an interface between the logical link control llc ethernet sublayer and layer 1 the physical layer.
Is the same concept as the multiplexing although this is a technique that can use different mechanisms. Aloha and difference between flow and access control. The mac sublayer aligns closely with the data link layer of the osi model, and is sometimes referred to by that name. Chapter 4 at montana state university bozeman studyblue. Mathematical preliminaries medium access protocols ethernet collisionfree protocols wireless ethernet wlan local area network. Media access control mac refers to the method used to allocate use of the medium among. In the open systems interconnection osi model of communication, the media access control layer is one of two sublayers of the data link control layer and is concerned with sharing the physical connection to the network among several computers. Analysis of medium access control protocols for home networks. Data link layer computer networks questions and answers this is the networking questions and answers section on data link layer with explanation for. Medium access control sublayer mahalingam ramkumar mississippi state university, ms february 26, 20 ramkumar mac. We are going to analyse them in depth here so we can get a firm understanding of them since they are part of the fundamentals of networking. The mac layer is responsible for moving data packets to and from one network interface card nic to another across a shared channel see a breakdown of the seven osi layers in the quick reference section of webopedia the mac sublayer uses mac protocols to ensure that signals sent. The portion of physical layer that interfaces with the.
Logical link control llc and media access control mac. Determines who is allowed to access the media at any one time as in csmacd and provides frame synchronization, which determines where one frame ends and the next begins. Introduction to the media access control mac layer 2. Can we apply media access methods from fixed networks. The lack of scalability of a fullyconnected network means that at some point we have to use fewer wires than our pointtopoint model requires.