Ppt is all about the standards of IEEE of family 802.X it includes the topics 802.3 & 802.11

1. IEEE 802.X
Keshav Maheshwari(15csu092)
Kritika Singh(15csu093)
Kshitij Sharma(15csu094)
Kuldeep Goel(15csu095)

2. Project 802
This are the standards for enabling
intercommunication among equipment from a
variety of manufacturers.
IEEE 802.3(Ethernet)

4. Ethernet
Ethernet is a family of computer networking technologies for local
area networks (LANs) and metropolitan area networks (MANs). It was
commercially introduced in 1980 and first standardized in 1983 as IEEE
802.3, [1] and has since been refined to support higher bit rates and longer
link distances.
Over time, Ethernet has largely replaced competing wired LAN
technologies such as token ring, FDDI, and ARCNET

6. MAC Sublayer :
In standard Ethernet , the MAC
sublayer ,governs
the operation of the access method .
And it also frames data received
from the upper layer and passes
them to the physical layer.
FRAME FORMAT
The Ethernet frames contains
seven fields : preamble ,SFD ,DA
,SA ,length or type of protocol data
unit(PDU),upper-layer data ,the
CRC . Ethernet does not provide
any mechanism for acknowledging
received frames , making it what is
known as an unreliable medium .

7. FRAME LENGTH : Ethernet has imposed restriction on both the minimum and
maximum lengths of a frame , as shown below.
Minimum frame length :512bits or 64 bytes
Maximum frame length:12,144bits/1518 bytes

8. 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
UNICAST AND MULTICAST ADDRESSES
-> The least significant bit of the first byte defines the type of address . If the bit is 0 ,the
address is unicast ; otherwise , it is 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.

10. 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

12. 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.

13. 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.

14. 10Base-T:Twister Pair Ethernet
● 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.

15. 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.

16. Fast 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.
UPGRADE TO FAST ETHERNET:
Upgrade the data rate to 100Mbps. Make it compatible with standard Ethernet.
Keep the same 48 bit-address. Keep the same frame format.Keep the same
minimum and maximum frame lengths .

17. Autonegotiation:
It is a new feature is added to the Fast Ethernet . It allows a station or a hub a
range of capabilities .
It was designed for the following purposes:
● To allow incompatible devices to connect to one another.
● To allow on devices to have multiple capabilities.
● To allow a station to check a hub’s capabilities .

18. Fast Ethernet implementation:

19. Gigabit Ethernet
● In computer networking, Gigabit Ethernet (Gb E or 1 GigE) is a term
describing various technologies for transmitting Ethernet frames at a rate of a
gigabit per second (1,000,000,000 bits per second), as defined by the IEEE
802.3-2008 standard.
● Fast Ethernet increased speed from 10 to 100 megabits per second (Mbit/s).
Gigabit Ethernet was the next iteration, increasing the speed to 1000 Mbit/s.
The initial standard for Gigabit Ethernet was produced by the IEEE in June
1998 as IEEE 802.3z, and required optical fiber. 802.3z is commonly referred
to as 1000BASE-X, where -X refers to either -CX, -SX, -LX, or (non-standard)
-ZX. For the history behind the "X" see Fast Ethernet.

20. Targets of Gigabit Ethernet:
● Upgrade the data rate to 1Gbps.
● Make it compatible with standard or fast Ethernet.
● Use the same address ,frame format.
● Keep the same minimum and maximum frame length.
● To support auto negotiation as defined in Fast Ethernet.

22. 1000BASE-SX
● 1000BASE-SX is a fiber optic Gigabit Ethernet standard for operation over
multi-mode fiber using a 770 to 860 nanometer, near infrared (NIR) light
wavelength.
● The standard specifies a distance capability between 220 meters (62.5/125
μm fiber with low modal bandwidth) and 550 meters (50/125 μm fiber with
high modal bandwidth).

23. 1000BASE-CX
● 1000BASE-CX is an initial standard for Gigabit Ethernet connection with
maximum distances of 25 meters using balanced shielded twisted pair and
either DE-9 or 8P8C connector (with a pinout different from 1000BASE-T).
The short segment length is due to very high signal transmission rate.
1000BASE-T
● 1000BASE-T (also known as IEEE 802.3ab) is a standard for Gigabit Ethernet
over copper wiring. Each 1000BASE-T network segment can be a maximum
length of 100 meters (330 feet), and must use Category 5 cable or better
(including Cat 5e and Cat 6).

24. 1000BASE-LX
● 1000BASE-LX is a fiber optic Gigabit Ethernet standard specified in IEEE
802.3 Clause 38 which uses a long wavelength laser (1,270–1,355 nm), and a
maximum RMS spectral width of 4 nm.
● 1000BASE-LX is specified to work over a distance of up to 5 km over 10 μm
single-mode fiber.

26. IEEE 802.11

27. Introduction
● Created and maintained by IEEE
● Set of media control(MAC) and physical layer
● Used to implement wireless local area network(WLAN)
● In the frequency band 2.4,3.6,5 and 60 GHz
● In the frequency band 2.4,3.6,5 and 60 GHz WLAN

28. Introduction cntd.
● Adopted in 1997
● Family of 802
● Origins in a 1985 ruling by the U.S. Federal Communications commission.
● Consist of series of half duplex over the air modulation.
● Uses same basic protocols
● It uses two spread spectrum technology
● Frequency Hopping Spread Spectrum (FHSS)
● Direct Sequence Spread Spectrum (DSSS)

29. General terminologies:
● BSS (basic service set):
○ Group of stations that communicate each other
○ IBSS(independent basic service set):
○ It is a BSS without access point
● Extended Service Set (ESS):
○ A set of one or more Basic Service Sets inter connected by a distribution System (DS).

30. BSS IBSS

31. General terminologies cntd:
● Service Set Identifier (SSID):
○ It is network name similar to domain id
○ One network (ESS or IBSS) has one SSID
○ Basic Service Set Identifier (BSSID)
○ It is cell identifier and is 6 octets long
○ Similar to NW ID in pre-IEEE Wave LAN systems

32. Frame format

33. The 802.11 Protocol Stack:

34. 802.11 Physical Layer (PHY)
● The 802.11 physical layer (PHY) is the interface between the MAC and the
wireless media where frames are transmitted and received.
● The PHY provides three functions.
○ First, the PHY provides an interface to exchange frames with the upper MAC layer for
transmission and reception of data.
○ Secondly, the PHY uses signal carrier and spread spectrum modulation to transmit data
frames over the media.
○ Thirdly, the PHY provides a carrier sense indication back to the MAC to verify activity on the
media.

35. Wireless Physical Layer:
● 802.11 Infrared
○ Two capacities 1 Mbps or 2 Mbps.
○ Range is 10 to 20 meters and cannot penetrate walls.
○ Does not work outdoors.
● 802.11 FHSS (Frequence Hopping Spread Spectrum)
○ The main issue is multipath fading.
○ 79 non-overlapping channels, each 1 Mhz wide at low end of 2.4 GHz ISM band.
○ Same pseudo-random number generator used by all stations. Dwell time: min. time on
channel before hopping(400msec).

36. Wireless Physical Layer:
● 802.11 DSSS (Direct Sequence Spread Spectrum)
○ Spreads signal over entire spectrum using pseudo-random sequence (similar to CDMA see
Tanenbaum sec. 2.6.2).
○ Each bit transmitted using an 11 chips Barker sequence, PSK
○ 1Mbaud.1 or 2 Mbps.
● 802.11a OFDM (Orthogonal Frequency Divisional Multiplexing)
○ Compatible with European HiperLan2.
○ 54Mbps in wider 5.5 GHz band transmission range is limited.
○ Uses 52 FDM channels (48 for data; 4 for synchronization).
○ Encoding is complex ( PSM up to 18 Mbps and QAM above this capacity).
○ E.g., at 54Mbps 216 data bits encoded into into 288-bit symbols. More difficulty penetrating
walls.

37. Wireless Physical Layer:
● 802.11b HR-DSSS (High Rate Direct Sequence Spread Spectrum)
○ 11a and 11b shows a split in the standards committee.
○ 11b approved and hit the market before 11a.
○ Up to 11 Mbps in 2.4 GHz band using 11 million chips/sec.
○ Note in this bandwidth all these protocols have to with interference from microwave ovens,
cordless phones and garage door openers.
○ Range is 7 times greater than 11a.
○ 11b and 11a are incompatible!!

38. Wireless Physical Layer
● 802.11g OFDM(Orthogonal Frequency Division Multiplexing)
○ An attempt to combine the best of both 802.11a and 802.11b.
○ Supports bandwidths up to 54 Mbps.
○ Uses 2.4 GHz frequency for greater range.
○ Is backward compatible with 802.11b.

39. 802.11 Mac Sublayer Protocol:
● In 802.11 wireless LANs, “seizing channel” not exist as in 802.3 wired
Ethernet.
● Two additional problems:
○ Hidden Terminal Problem
○ Exposed Station Problem
● To deal with these two problems 802.11 supports two modes of operation
DCF (Distributed Coordination Function) and (Point Coordination Function).
● All implementations must support DCF, PCF is optional.

40. .(a)The hidden station problem. (b) The exposed station problem.

41. Wireless Lan Protocols:
● MACA protocol solved hidden, exposed terminal:
○ Send Ready-to-Send (RTS) and Clear-to-Send (CTS) first
○ RTS, CTS helps determine who else is in range busy (Collision avoidance).
○ Can a collision still occur?

42. Wireless LAN Protocols:
● MACAW added ACKs and CSMA (no RTS at same time).
(a) A sending an RTS to B. (b) B responding with a CTS to A.

43. THANK YOU