Ethernet Computer network

Ethernet Computer network

1. Wired LANs:Ethernet 1 Presented By:- Kuldip kaklotar Mitesh Chaudhari

2. 2 What Is Ethrenet? Ethernet is a family of computer networking technologies commonly used in local area networks, metropolitan area networks and wide area networks. It was commercially introduced in 1980 and first standardized in 1983 as IEEE 802.3, and has since been refined to support higher bit rates and longer link distances.

3. 3 Types Of Ethernet Fast Ethernet Ten-Gigabit Ethernet Standard Ethernet Gigabit Ethernet

4. 4 Specified in the family of standards known as IEEE  802.3 , Ethernet was originally developed by Xerox in the 1970s. Ethernet was initially designed to run over coaxial cables, but a typical Ethernet LAN now uses special grades of  twisted pair  cables, or fiber optical cabling. Wi-Fi standards (IEEE 802.11a , b, g, n and now ac) define the equivalent of Ethernet for  Wireless LAN s.) Ethernet standards are steadily evolving to embrace new media, higher transmission speeds and changes in frame content (e.g., 802.3ac to accommodate  VLAN  and priority tagging) and functional requirements (e.g., 802.3af, defining  Power Over Ethernet [POE] crucial to most Wi-Fi and IP telephony deployments)

5. 5 Data Link Layer The data link layer is used for the encoding, decoding and logical organization of data bits. Data packets are framed and addressed by this layer, which has two sublayers . The data link layer's first sublayer is the media access control (MAC) layer. It is used for source and destination addresses. The MAC layer allows the data link layer to provide the best data transmission vehicle and manage data flow control . The data link layer's second sublayer is the logical link control . It manages error checking and data flow over a network

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7. 7 Logical Link Control The Logical Link Control ( LLC) layer is one of two sublayers of the Data-Link layer in the Open Systems Interconnection ( OSI ) model of communication. The LLC layer is concerned with managing traffic (flow and error control) over the physical medium. The LLC layer also identifies a line protocol, such as  SDLC ,  NetBIOS , or  NetWare , and may also assign sequence numbers to  frame s and track acknowledgements. The other Data-Link sublayer is the  Media Access Control layer

8. 8 Media Access C ontrol MAC,  M edia  A ccess  C ontrol, address is a globally unique identifier assigned to network devices, and therefore it is often referred to as hardware or physical address. MAC addresses are 6-byte (48-bits) in length, and are written in MM:MM:MM:SS:SS:SS format. The first 3-bytes are ID number of the manufacturer, which is assigned by an Internet standards body. The second 3-bytes are serial number assigned by the manufacturer . MAC layer represents layer 2 of the  TCP/IP  (adopted from OSI Reference Model), where IP represents layer 3. MAC address can be thought of as supporting hardware implementation whereas IP address supports software implementation .

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10. START FRAME DELIMITER(SFD) :The second field (1byte:10101011)signals the beginning of the frame . The SFD warns the station that this is the last chance for synchronization . The last 2 bits is11 and alerts the receive that the next field is the destination address. DESTINATION ADDRESS(DA) :The DA field is 6bytes and contain the physical address of the destination station to receive the packet SOURCE ADDRESS : The SA field is also 6 bytes and contains the physical address of the sender of the packet. LENGTH/TYPE : This field is defined as a type field or length field.Theoriginal Ethernet used this field as the type field to define the upper –layer protocol using the MAC frame. DATA : This field carries data encapsulated from the upper –layer protocols.It is a minimum of 46 and a maximum of 1500 bytes. CRC : The last filed contains error detection information,in this case a CRC-32.

11. 12 Physical Layer The physical layer is the first layer of the Open System Interconnection Model (OSI Model). The physical layer deals with bit-level transmission between different devices and supports electrical or mechanical interfaces connecting to the physical medium for synchronized communication.  This layer plays with most of the network’s physical connections - wireless transmission, cabling, cabling standards and types, connectors and types, network interface cards, and more The physical layer is aimed at consolidating the hardware requirements of a network to enable the successful transmission of data Network engineers can define different bit-transmission mechanisms for the physical layer level, including the shapes and types of connectors, cables, and frequencies for each physical medium. 

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13. 14 IEEE Standards

14. 15 802 Standards. IEEE 802.2, 802.3, 802.5, 802.11 The Institute of Electrical and Electronics Engineers is a standards setting body. Each of their standards is numbered and a subset of the number is the actual standard. The 802 family of standards is ones developed for computer networking. In this section, you will learn: - What the 802.2, 802.3, 802.5, 802.11 standards encompass; - Features, topology, and network cabling for each of these standars . First, let's discuss 802. IEEE, or Institute of Electrical and Electronics Engineers, is a standards setting body. They create standards for things like networking so products can be compatible with one another. You may have heard of IEEE 802.11b - this is the standard that IEEE has set (in this example, wireless-b networking). In this section, we will look at several networking technologies: 802.2, 802.3, 802.5, 802.11, and FDDI. Each of these is just a standard set of technologies, each with its own characteristics.

15. 16 802.2 Logical Link Control The technical definition for 802.2 is "the standard for the upper Data Link Layer sublayer also known as the Logical Link Control layer. It is used with the 802.3, 802.4, and 802.5 standards (lower DL sublayers )." 802.2 "specifies the general interface between the network layer (IP, IPX, etc) and the data link layer ( Ethernet, Token Ring, etc ). Commonly referred to as the LLC or Logical Link Control specification. The LLC is the top sub-layer in the data-link layer, OSI Layer 2. Interfaces with the network Layer

16. 17 802.3 Ethernet " Grandaddy " of the 802 specifications. Provides asynchronous networking using "carrier sense, multiple access with collision detect" (CSMA/CD) over coax, twisted-pair copper, and fiber media. Current speeds range from 10 Mbps to 10 Gbps .

17. 18 802.5 Token Ring The original token-passing standard for twisted-pair, shielded copper cables. Supports copper and fiber cabling from 4 Mbps to 100 Mbps. Often called "IBM Token-Ring."

18. 19 802.11 WIFI Wireless LAN Media Access Control and Physical Layer specification. 802.11a,b,g,etc. are amendments to the original 802.11 standard. Products that implement 802.11 standards must pass tests and are referred to as "Wi-Fi certified."

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20. 21 10Base2:Thin Internet The second implementation is called 10Base2,thin Ethernet , cheaper net . The cable is thinner and more flexible. The transceiver is a part of NIC , which is installed inside the station. The implementation is most cost effective than 10Base5as thin coaxial cable is less expensive than thick coaxial cable and the tee connection are much cheaper than taps.

21. 22 10Base5:Thick Internet The name 10BASE5 is derived from several characteristics of the physical medium. The 10 refers to its transmission speed of 10 Mbit /s. The BASE is short for baseband signaling as opposed to broadband, and the 5 stands for the maximum segment length of 500 meters (1,600 ft.). It was the first Ethernet specification to use a bus topology with a external transceiver connected via a tap to a thick coaxial cable. 10Base5:Thick Internet

22. 23 10Base-T:Twisted Pair The third implementation is called 10Base- T or Twisted Pair Ethernet. It uses star topology and the station are connected via two pairs of twisted cable(one fro sending and one for receiving)between the station and the hub. The maximum length of the twisted cable here is defined as 100m,to minimize the effect of attenuation in the twisted cable.

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25. 26 10Base-F:Fiber Ethernet Although there are several types of optical fiber 10Mbps Ethernet , the most common is called 10Base-F. 10Base-F uses a star topology to connect stations to a hub. The stations are connected to a hub using two-optic cables.

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28. 29 CHANGES IN THE STANDAR Bridged Ethernet Switched Ethernet

29. 30 Bridge Ethernet The first step in the Ethernet evolution was the division of a LAN by bridge. Bridges have two effects on an Ethernet LAN 1) Raising Bandwidth 2 ) Collision of domains   1)Raising Bandwidth Unbridged Ethernet network, the total capacity ( 10Mbps) is shared among all station with a frame to send; the stations share the bandwidth of the network. If only one station has frames to send, it benefits for the total capacity (10Mbps). But if more than one station needs to use the network, the capacity is shared.

30. 31 Sharing Bandwidth

31. 32 Network Without bridge and with a bridge.

32. 33 Separating collision domains A   collision domain  is a  network  segment connected by a shared medium or through repeaters where data packets may  collide  with one another while being sent. ... A network collision  occurs when more than one device attempts to send a packet on a  network  segment at the same time.

33. 34 Switch Ethernet An   Ethernet LAN  that uses switches to connect individual hosts or   segments . In the case of individual hosts, the switch replaces the  repeater and effectively gives the device full 10 Mbps  bandwidth to the rest of the network .  In the case of segments, the  hub is replaced with a switching hub. In traditional Ethernets, in which all hosts compete for the same bandwidth, are called  shared Ethernets .

34. 35 Switched Ethernets are becoming very popular because they are an effective and convenient way to extend the bandwidth of existing Ethernets . The figure of switch Ethernet is as below.

35. 36 One of the limitations of 10Base5 and 10Base2 is that communicati9on is half-duplex(10Base-T is always full-duplex ). A station can either send or receive , but may not do both. Full-duplex switched Ethernet mode increase the capacity of each domain from 10 to 20 Mbps Instead of using one link between the station and the switch , the configuration user two links: one to transmit and to receive. Switch Ethernet in full duplex mode

36. 37 Switch in Full duplex mode

37. 38 Each station or switch can send and receive independently without worrying about collision. Each link is a point to point dedicated path between the station and the switch. There is no longer a need for carrier sensing and no need for collision detection. The job of the MAC layer becomes much easier.

38. 39 MAC Control Layer Stander Ethernet was designed as a connectionless protocol at the MAC sublayer. There is no explicit flow control or error control to inform the sender that the frame has arrived at the destination without error. When the receiver receives the frame it does not send any positive or negative acknowledgement.

39. 40 Fast Ethernet Fast Ethernet was designed to compete with LAN protocols such as FDDI or fiber Channel. IEEE created Fast Ethernet under the name 802.3u. Fast Ethernet is backward-compatible with Sander Ethernet, but it can transmit data 10 time faster at a rate of 100 Mbps . The goal of the fast Ethernet as below :- Upgrade the data rate at the 100 Mbps. :- Make it compatible with standard Ethernet. :- Keep the same frame format.

40. 41 MAC sublayer A main Consideration in the evolution of Ethernet from 10 to 100 Mbps was to keep the MAC sublayer untouched. A decision was made to drop the bus topology and keep only the star topology. For the star topology there are two choices, as we say before: Half duplex and Full duplex approach, the connection is made via a switch without buffers at each port.

41. 42 A new feature added to fast Ethernet is called Autonegotiation. It allows a station or hub a range of capabilities. To allow incompatible devices to connect to one another. For example a device with a maximum capacity of 10 Mbps can communicate with a device a 100 Mbps capacity (but can work at a lower rete ). To allow one device to have multiple capabilities. To allow a station to check a hub’s capabilities.

42. 43 Physical Layer The Physical layer In Fast Ethernet is more complicated than the one in Standard Ethernet . Topology:- Fast Ethernet is designed to connect two or more stations together . If there are only two stations, they can be connected point to point. If there are there or more stations need to be connected in a star topology with a hub or a switch at the center

43. 44 The figure of two station which are connected to point to point. I n the star topology the station are more then two are connected with switch

44. 45 Implementation Fast Ethernet implementation at the physical layer can be categorized as either two-wire or four-wire. The two-wire implementation can either category 5 UTP(100base-TX) or fiber-optic cable (100Base-FX). The four-wire implementation is designed only for category 3 UTP (100base-T4 ). Let’s understand with figure which is as below.

45. 46 100Base-TX uses two pairs of twisted-pair cable(either category 5 UTC or STP). 100Base-FX uses two pairs of fiber cables. Optical fiber can easily handle high bandwidth requirement by using simple encoding schemes . A 100Base-TX network can provide a data rate of 100 Mbps, but it requires the use of category 5 UTP or STP cable.

46. 47 Gigabit Ethernet The need for an even higher data rate resulted in the design of the Gigabit Ethernet protocol (100Mbps ). The IEEE committee calls the Standard 802.3z. The goal of the Gigabit Ethernet design can be summarized as below . 1 Upgrade the data rate to 1Gbps. 2 Make it compatible with Standard of Fast Ethernet. 3 Use the same frame format. 4 Keep the same minimum and maximum frame lengths.

47. 48 MAC sublayer A main consideration in the evolution of Ethernet was to keep the MAC sublayer untouched. However to achieve data rate 1 Gbps this was longer possible. Gigabit Ethernet has two distinctive approaches for medium access: half duplex and full duplex.

48. 49 Full Duplex Mode In full duplex mode there is a central switch connected to all computers or other switches . In this mode each switch has buffers for each input port in which data are stored until they are transmitted . There is no collision implies that the maximum length of the cable is determined by the signal attenuation in the cable not by the collision detection process.

49. 50 Half Duplex mode Gigabit Ethernet can also be used in half-duplex mode, although it is rare. In this case a switch can be replaced by a hub, which acts as the common cable in which a collision might occur

50. 51 Physical Layer The physical layer in Gigabit Ethernet is more complicated than that in standard or fast Ethernet. Topology Gigabit Ethernet is designed to connect two or more stations. If there are only two stations, they can be connected point to point. There are three or more stations need to be connected in a star topology with a hub or a switch at the center.

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52. 53 Gigabit Ethernet implementations

53. 54 The IEEE committee created Ten-Gigabit Ethernet and called it Standard 802.3ae. The goal of Ten Gigabit Ethernet design can be summarized as follow . 1 Upgrade the date rate to 10Gbps . 2 Make it compatible with Standard, fast. 4 Use the same frame format. 5 Keep the same minimum and maximum frame lengths. Ten Gigabit Ethernet

54. 55 MAC Sublayer Ten-Gigabit Ethernet operates only in full duplex mode. Physical Layer The physical layer in Ten-Gigabit Ethernet is designed for using fiber-optic cable over long distances . Three implementations are the most common: 10GBase-s , 10GBase-L and 10GBase-E.

55. 56 Summary of Ten –Gigabit Ethernet implementations

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