Local Area Networks: Ethernet

1. Local Area Networks:Ethernet

2. Institution of Electrical and Electronic Engineering (IEEE) A professional non-profit organization Project group 802 under IEEE Entrusted with the task of setting standards relating to physical and logical links of nodes in a network Standard mostly applies to the Physical and Data Link layers Example IEEE 802.3 standard for the Ethernet bus network IEEE Background

3. OSI Reference Data Link layer Physical layer Areas of applications Network cards and cables WAN connectivity etc. Different subgroups under 802 that focus on different activities of the LAN IEEE 802 Focus

4. 802.1 Internetworking 802.2 Logical Link Control (LLC) 802.3 CSMA/CD 802.4 Token Bus LAN IEEE 802 Subgroups and their Responsibilities

5. 802.5 Token Ring LAN 802.6 Metropolitan Area Network 802.7 Broadband Technical Advisory Group 802.8 Fiber-Optic Technical Advisory Group IEEE 802 Subgroups and their Responsibilities (Cont.)

6. 802.9 Integrated Voice/Data Networks 802.10 Network Security 802.11 Wireless Networks 802.12 Demand Priority Access LANs Ex: 100BaseVG-AnyLAN IEEE 802 Subgroups and their Responsibilities (Cont.)

7. A Perspective of IEEE 802 Standards in Network Communication Logical Link Control (LLC) 802.2 802.1 applies to both. Media Access Control (MAC) 802.3 802.4 802.5 802.12

9. Encoding/decoding Preamble generation/removal Bit transmission/reception Transmission medium and topology 802 Layers - Physical

10. Flow control, Error control,& part of the framing Transmission of link level PDUs between two stations Must support multiaccess, shared medium Relieved of some link access details by MAC layer LLC defines PDU similar to HDLC Addressing involves specifying source and destination LLC users Referred to as service access points (SAP) Typically higher level protocol Logical Link Control

11. Three generations of Ethernet

12. 802.3 MAC frame Preamble: Provides an alert & a timing pulse SFD: Signals the beginning of the frame,& also warns the stations that this is the last the chance for synchronization. Last 2 bits alerts the receiver that next field is the destination address DA & SA : Physical address of receiver & sender Length or type: Define the upper layer protocol using the MAC frame IEEE use as length field to define the number of bytes in the data field

13. Minimum and maximum length If 18 bytes of header and trailer(6 SA + 6 DA + 2 Length + 4 CRC) Then Minimum length of data from the upper layer is 64-18= 46 bytes If the upper-layer packet is less than 46 bytes, padding is added to make up the difference

14. Ethernet addresses in hexadecimal notation

15. Unicast and multicast addresses Source address is always a unicast address Destination address can be unicast, multicast ,or broadcast LSB of the 1st byte defines the type of address Broadcast DA is a special case of the multicast address in which all bits are 1s

16. Access method: standard ethernet uses 1-persistent CSMA/CD SLOT TIME: round trip time + time required to send the jam sequence Defined in bits,time required to send 512 bits Depends on the data rate For 10-Mbps ethernet it is 51.2 μs

17. Physical layer

18. PLS

19. Manchester encoding

20. Categories of traditional Ethernet 10Base5,thick Ethernet, thicknet, Max length 500 m (coaxial cable) 10 base2,Thin coaxial cable,185 m, bus topology 10base-T,twisted pair Ethernet, physical star topology,100 m max length 10base-F,fiber,2000m,star topology

21. Connection of a station to the medium using 10Base5

22. Connection of stations to the medium using 10Base2

23. Connection of stations to the medium using 10Base-T

24. Connection of stations to the medium using 10Base-FL

25. Sharing bandwidth

26. A network with and without a bridge

27. Collision domains in a nonbridged and bridged network

28. Switched Ethernet

29. Full-duplex switched Ethernet

30. Fast Ethernet MAC Sublayer Physical Layer Physical Layer Implementation IEEE 802.3u

31. Fast Ethernet physical layer

32. Upgrade the data rate to 100 Mbps Compatible with standard Ethernet Same 48-bit address Same frame format Same Min & Max frame lenths Goal of Fast Ethernet

33. For full-duplex no need of CSMA/CD Autonegotiation - Allows station or a hub a range of capabilities - Allow to negotiate the mode or data rate of operation MAC sublayer

34. MII

35. Fast Ethernet implementations

36. 100Base-TX implementation

37. Encoding and decoding in 100Base-TX Four Binary/Five binary coding scheme Multiline Transmission(three levels) Use 2 pairs of twisted pair cable Use MLT-3,as it has good bandwidth performance

38. MLT-3 signal

39. 100Base-FX implementation 2 pair fiber cable, 100 m,4B/5B block coding,NRZ-I line coding

40. Encoding and decoding in 100Base-FX

41. 100Base-T4 implementation Cat 4 UTP,4 pair of wires,100 Mbps * Data elements are encoded as six signal elements

42. Using four wires in 100Base-T4

43. Gigabit Ethernet MAC Sublayer Physical Layer Physical Layer Implementation

44. Physical layer in Gigabit Ethernet

45. Traditional: 512 bits,length of bit is 1/100 shorter,slot time=.512microsec Carrier extension: Min length of a frame is 512 bytes Frame bursting: Three Methods for Gigabit ethernet

46. Gigabit Ethernet implementations 2 wire Short,longwave(sx,Lx), STP CX,NRZ line encoding 4 wire use Twiste pair category 5 4D-PAMS line encoding Block coding is 8B/10B

47. 1000Base-X implementation

48. Encoding in 1000Base-X

49. 1000Base-T implementation

50. Encoding in 1000Base-T