1. Chaithra 1741113 Ashwin 1741130 Sanjana 1741146
Ethernet
Chaithra
Ashwin
Sanjana

2. 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.

3. 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)
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4. 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.

5. 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.

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

7. ETHERNET FRAME

8. 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.

9. 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

10. 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.

11. 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)

12. 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

13. 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

14. 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( )
Preamble
SFD
Destination address
Source address
Length/Type
Data and padding
CRC
7bytes
1byte
6 bytes
6bytes
2bytes
4bytes
Physical layer header

15. 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

16. 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 ( )– 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

17. 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 ( byte).
CRC: Error detection method.
ADAD

18. Media access control
According to IEEE Std section "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 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