Chaithra 1741113 Ashwin 1741130 Sanjana 1741146 Ethernet Chaithra 1741113 Ashwin 1741130 Sanjana 1741146

INTRODUCTION Project 802 is a project that’s et standards or way of specifying functions of the physical layer and the data link layer of major LAN protocols.

IEEE STANDARD FOR LANS LLC : Logical link control MAC :Media access control Upper Layers Data link layer Physical Layer Transmission medium (OSI/Internet model) Upper layers LLC Ethernet MAC Token Ring MAC Token Bus MAC … Ethernet Physical Layers (several) Token Ring Physical Layer Token Bus Transmission Medium (IEEE STANDARD) - - - - - -

ETHERNET  ETHERNET is the traditional technology for connecting wired LANs, enabling devices to communicate with each other via a protocol-a set of rules or common network language.

Ethernet provides services up to and including the data link layer which is divided into 2 sublayers: LLC & MAC. DATA LINK LAYER  Logic Link Control: Provides interconnectivity between different LANs.  Media Access Control: Frames data received from the upper layer & passes to the physical layer. PHYSICAL LAYER: It defines transmission of raw bits rather than data packets.

ETHERNET 10Mbps 100Mbps 1Gbps 10Gbps STANDARD ETHERNET FAST ETHERNET GIGABIT ETHERNET TEN GIGABIT ETHERNET 10Mbps 100Mbps 1Gbps 10Gbps

ETHERNET FRAME

FRAME LENGTH : Ethernet has imposed restriction on both the minimum and maximum lengths of a frame , as shown below Destination address Source address Length PDU Data and padding CRC 6 bytes 6 bytes 2 bytes 4 bytes Minimum frame length :512bits or 64 bytes Maximum frame length:12,144bits/1518 bytes REQUIREMENT OF MIN/MAX LENGTH: The minimum length is required for the correct operation of CSMA/CD. The maximum length is used to reduce the size of the buffer. It also prevents one station from monopolizing the shared medium.

ADDRESSING : Each station on a Ethernet network(such as PC ,workstation or printer) has its own network interface card(NIC).The NIC fits inside the station and provides the station with a 6-byte physical address . The Ethernet address is 6bytes(48 bits)written in hexadecimal notation , with a colon between the bytes. Example: 06:01:02:01:2C:4B 6bytes =12 hex digits=48 bits

UNICAST AND MULTICAST A unicast address defines only one recipient ; the relationship between the sender and the receiver is one-to-one. A multicast address defines a group of addresses ; the relationship between the sender and the receiver is one-to-many. The broadcast destination address is a special case of the multicast address in which all bits are 1s.

Example 4A:30:10:21:10:1A This is a unicast address because A in binary is 1010 (even). 47:20:1B:2E:08:EE This is a multicast address because 7 in binary is 0111 (odd). FF:FF:FF:FF:FF:FF This is a broadcast address because all digits are Fs in hexadecimal. (All bits are 1)

ACCESS METHOD : CSMA / CD Standard Ethernet uses 1-persistent CSMA/CD SLOT TIME: Slot time=round-trip time + time required to send the jam sequence RELATIONSHIP BETWEEN SLOT TIME AND MAXIMUM NETWORK LENGTH: Max Length=Propagation speed ×slot time 2

MAC Sublayer/ Ethernet Frame The Media Access Control Layer is a sublayer of data link layer. The MAC layer is responsible for moving data packets to and from one Network Interface Card (NIC) to another across a shared channel. Uses MAC protocols to ensure that signals sent from different stations across the same channel don't collide. Protocol example: Ethernet

MAC Sublayer : In standard Ethernet ,the MAC sublayer governs 802.3 MAC frame: Preamble:56 bits if alternating 1s and 0sSFD:Strat frame delimiter ,flag(10101011) Preamble SFD Destination address Source address Length/Type Data and padding CRC 7bytes 1byte 6 bytes 6bytes 2bytes 4bytes Physical layer header

Standard Ethernet In Standard Ethernet, the MAC sublayer rules the operation of access method. It frames data received from the upper layer and passes them to the physical layer. 803.2 MAC frame ADAD

Frame Format – Standard Ethernet (802.3 MAC sublayer) PREAMBLE : 7 bytes (56 bits) of alternating 0s and 1s Alerts the system to the coming frame and enables it to synchronize its input timing. Pattern provide only alert and timing pulses. Actually added by physical layer (not necessary). START FRAME DELIMITER (SFD): 1 byte (10101011)– signals beginning of the frames. Warns the station that it is last chance for synchronization. Last 2 bits (11) – alerts the receiver that the next field is the destination address. ADAD

Frame Format – Standard Ethernet (802.3 MAC sublayer) Destination Address: 6 bytes – physical address of the destination. Source Address: 6 byte – physical address of the sender. Length or Type: Define upper layer protocol using MAC frame. Data: Encapsulated data from upper layer protocols (46-1500 byte). CRC: Error detection method. ADAD

Media access control According to IEEE Std 802-2001 section 6.2.3 "MAC sublayer", the primary functions performed by the MAC layer are: Frame delimiting and recognition Addressing of destination stations (both as individual stations and as groups of stations) Conveyance of source-station addressing information Transparent data transfer of LLC PDUs, or of equivalent information in the Ethernet sublayer Protection against errors, generally by means of generating and checking frame check sequences Control of access to the physical transmission medium In the case of Ethernet, according to 802.3-2002 section 4.1.4, the functions required of a MAC are: receive/transmit normal frames half-duplex retransmission and backoff functions append/check FCS (frame check sequence) interframe gap enforcement discard malformed frames append(tx)/remove(rx) preamble, SFD (start frame delimiter), and padding half-duplex compatibility: append(tx)/remove(rx) MAC address