 Hello everyone, today we are going to learn IEEE standards 802 for LAN. The learning outcomes are at the end of this session student will be able to describe IEEE 802.3 standard for LAN that is Ethernet. They will differentiate the various type of cabling used by Ethernet. Now let's see the overview of IEEE 802.2 standard. IEEE stands for Institute of Electrical and Electronics Engineers. IEEE has produced several standards for LAN which are known as IEEE 802 standards. These standards are divided into various parts and these parts are explained with the help of this table. IEEE 802.1 standard define the set of standards and interface primitives. IEEE 802.2 standard describe the LLC that is Logical Link Control Protocol which is the lower layer protocol of data link layer of TCPIP protocol suite. IEEE 802.3 standard describe the LAN standard that is CSMSCD which is also known as Ethernet. IEEE 802.4 describe the LAN standard token bus and IEEE 802.5 standard describe the token ring. There are several standards which are described by IEEE 802. In this session we are mainly focusing on IEEE 802.3 standard that is Ethernet. IEEE 802.3 use for the one persistent CSMSCD LAN. CSMSCD stands for Career Sense Multiple Access Protocol with Collision Detection. In this protocol when station want to send the frame it senses the medium or it listen the medium or channel. When the medium is idle it immediately transmit the frame that means the 100% transmission of frame but if the channel is idle it wait until it goes idle. When more than two station want to transmit the frame they senses the medium and simultaneously transmit their transmission. In the transmission the frames are collided. Once the frames are collided it immediately the station and station terminate their transmission. So this procedure is repeat again. This procedure is known as one persistent CSMSCD and IEEE 802.3 standard uses this medium access mechanism. It uses the bus and star topology. It implement the CSMSCD as the medium access method. Now let's see the history of IEEE 802.3 standard. It is found by Xerox Palo Alto Research Center in 1975. It originally designed as a 2.94 Mbps system to connect the 100 computers on a 1 km cable which is also known as the Ethernet. In latter the Xerox, Intel and DEC drive up the standard supports 100 Mbps Ethernet. Now these are the Ethernet basic. As I said earlier the topology it uses is linear bus and star bus. Signalling is mainly baseband signal which is the digital signal and the access method is CSMSCD. Its specification is IEEE 802.3. Its transfer speed is 10 Mbps, 100 Mbps and above and it uses the cable coaxial cable and UTP. UTP stands for unshielded twisted pair. Now the name Ethernet indicates the cable. So there are various cabling techniques provided by 802.3 standard. So let's see the various type of cabling. The first type of cable is 10-5, 10-2, 10-T and 10-F. So let's see 10-5 type of cabling in detail. So here 10 stands for data rate in Mbps. Then base is for baseband signal and 5 is for cable type or length limit. That means the 10-5 indicates the data rate, signalling method and maximum segment length or cable type. Let me explain the 10-5 in detail. So it operates at 10 Mbps speed, uses the baseband signalling and can support the segment of up to 500 meters. That means in a connection after every 500 meter segment is allowed. It is also known as thick Ethernet. Now this diagram shows the number of PCs are connected to coaxial cable and that coaxial cable is known as thick Ethernet. Now in detail we will see how this coaxial cable is connected to terminal. So here vampire tab is used for the connection. This vampire tab is inserted into the core of coaxial cable and the other end of this transceiver cable is connected to the interface board. So the transceiver cable connects the interface board where the controller is present. So this interface board contains the controller chip. Controller chip having the various responsibilities, it just see whether the frame is transmitted to and from transceiver. It also compute the checksum. It also assemble the proper frame format. And it also having the pool of, it also having the pool of buffer which is used to see whether the frame is transmitting or it just check whether the outgoing frame and incoming frame are coming or not. Then here the transceiver cable consists of individual 5 twisted pair cable, 2 are for data in and out, 2 are for control signal in and out and 1 is to provide the power to transceiver. The time domain reflectometry is used to detect the cable breaks, bad tabs or loose connection. Let me explain the time domain reflectometry. So basically a pulse of known shape is injected into the cable. If that pulse is hits to an obstacle or at the end of cable it generates the eco and send back. So the time interval in between sending the signal and receiving the eco will generates the eco origin and this will help to find out the breaks, bad tabs or loose connection. Now let's see the second type of cabling that is 10 base 2. It operates at 10 mbps speed, uses the baseband signaling and can support the segments of up to 200 meters. It is also known as thin ethernet. Now let's see this diagram. Here it is connected with the help of BNC connector. So the BNC connectors are used for their connection to make the T junction instead of vampire tab. Transceivers, electronics are on the controller board. It is easy to use and more reliable, easier to install and cheaper. But the disadvantage is only 30 machines are allowed per segment. Again the time domain reflectometry is used to detect the cable breaks, tab, bad tabs or the loose connection. Now the third type of cabling is 10 base T. It operates at 10 mbps speed, uses the baseband signaling and can support the segments of up to 10 meters. It uses the twisted pair cable and the maximum cable run from the hub is 100 meter. So this diagram shows how the hub is used to connect the each and every terminal. So there are so many twisted pair cables coming from hub and which are connected to the terminals. The star topology is used by 10 base T and the cable breaks can be detected easily. Why? Because here the individual twisted pair is connected to the individual terminal and that is why adding or removing the station is very simple. Now pause the video, think about this question and write down the answer. The question is differentiate between baseband signaling and broadband signaling. Now baseband signaling uses the digital signal whereas broadband signals uses the analog signal. Baseband signals work well with burst topology and broadband signals work well with burst and tree topology. Baseband communication is bidirectional whereas broadband is unidirectional. Signals can be travelled over the short distance and in broadband it uses the long distance. Baseband uses the TDM whereas broadband uses the FDM that is frequency division multiplexing. Now the last type of cabling is 10 base F. It operates at 10 Mbps and uses the baseband signaling and can support the segments of up to 200 meter. It uses the fiber optic cable, star topology is used and expensive due to the cost of connectors and terminal and excellent noise immunity. This 10 base F has an excellent noise immunity. Now this table indicates the comparison of 802.3 type of cabling. So 10 base 5 is known as thick ethernet. The maximum segments are after every 500 meters and only 100 nodes are allowed per segment which is good for the backbone. 10 base 2 is a thick ethernet and the maximum segment is 200 meter and only 30 nodes are allowed per segment. It is the cheapest and easy to install. 10 base T is a twisted pair and the maximum segment allowed after every 100 meter. But 1024 nodes are allowed per segment, it is easy for maintenance. Then the 10 base F which uses the optical fiber which provides the very high immunity, very high noise immunity and the segments are allowed after 2 kilometers and the number of nodes per segments are 1024 and it is best between the buildings. These are the references. Thank you.