LAN TOPOLOGIES BUS RING STAR BUS TOPOLOGY 1

LAN TOPOLOGIES • BUS • RING • STAR

BUS TOPOLOGY - 1 • STATIONS ATTACH TO LINEAR MEDIUM (BUS) • VIA A TAP - ALLOWS FOR TRANSMISSION AND RECEPTION • TRANSMISSION PROPAGATES IN MEDIUM IN BOTH DIRECTIONS • RECEIVED BY ALL OTHER STATIONS • NOT ADDRESSED STATIONS IGNORE • NEED TO IDENTIFY TARGET STATION • EACH STATION HAS UNIQUE ADDRESS • DESTINATION ADDRESS INCLUDED IN FRAME HEADER • TERMINATOR ABSORBS FRAMES AT THE END OF MEDIUM

BUS TOPOLOGY - 2 • NEED TO REGULATE TRANSMISSION • TO AVOID COLLISIONS • IF TWO STATIONS ATTEMPT TO TRANSMIT AT SAME TIME, SIGNALS WILL OVERLAP AND BECOME GARBAGE • TO AVOID CONTINUOUS TRANSMISSION FROM A SINGLE STATION. IF ONE STATION TRANSMITS CONTINUOUSLY, ACCESS IS BLOCKED FOR OTHERS • SOLUTION: TRANSMIT DATA IN SMALL BLOCKS – FRAMES

RING TOPOLOGY • REPEATERS JOINED BY POINTTO-POINT LINKS IN CLOSED LOOP • LINKS ARE UNIDIRECTIONAL • RECEIVE DATA ON ONE LINK AND RETRANSMIT ON ANOTHER • STATIONS ATTACH TO REPEATERS • DATA TRANSMITTED IN FRAMES • FRAME PASSES ALL STATIONS IN A CIRCULAR MANNER • DESTINATION RECOGNIZES ADDRESS AND COPIES FRAME • FRAME CIRCULATES BACK TO SOURCE WHERE IT IS REMOVED • MEDIUM ACCESS CONTROL IS NEEDED TO DETERMINE WHEN STATION CAN INSERT FRAME

FRAME TRANSMISSION RING LAN

STAR TOPOLOGY • EACH STATION CONNECTED DIRECTLY TO CENTRAL NODE • USING A FULL-DUPLEX (BI-DIRECTIONAL) LINK • CENTRAL NODE CAN BROADCAST (HUB) • PHYSICAL STAR, BUT LOGICALLY LIKE BUS DUE TO BROADCAST MEDIUM • ONLY ONE STATION CAN TRANSMIT AT A TIME; OTHERWISE, COLLISION OCCURS • CENTRAL NODE CAN ACT AS FRAME SWITCH • RETRANSMITS ONLY TO DESTINATION • TODAY’S TECHNOLOGY Hub or Switch

IEEE 802. 1 HIGHER LAYER LAN PROTOCOLS IEEE 802. 2 LOGICAL LINK CONTROL IEEE 802. 3 ETHERNET IEEE 802. 4 TOKEN BUS IEEE 802. 5 TOKEN RING IEEE 802. 6 METROPOLITAN AREA NETWORKS IEEE 802. 7 BROADBAND LAN USING COAXIAL CABLE IEEE 802. 8 FIBER OPTIC TAG IEEE 802. 15 WIRELESS PAN IEEE 802. 15. 1 (BLUETOOTH) IEEE 802. 15. 4 (ZIGBEE) IEEE 802. 16 BROADBAND WIRELESS ACCESS (WIMAX) IEEE 802. 16 E (MOBILE) BROADBAND WIRELESS ACCESS IEEE 802. 17 RESILIENT PACKET RING IEEE 802. 9 INTEGRATED SERVICES LAN IEEE 802. 18 RADIO REGULATORY TAG IEEE 802. 10 INTEROPERABLE LAN SECURITY IEEE 802. 19 COEXISTENCE TAG IEEE 802. 11 WIRELESS LAN (WI-FI) IEEE 802. 20 MOBILE BROADBAND WIRELESS ACCESS IEEE 802. 12 DEMAND PRIORITY IEEE 802. 21 MEDIA INDEPENDENT HANDOFF IEEE 802. 14 CABLE MODEMS IEEE 802. 22 WIRELESS REGIONAL AREA NETWORK

ETHERNET IEEE 802. 3

ETHERNET AND IEEE 802. 3 ETHERNET IS A BASEBAND LAN SPECIFICATION INVENTED BY XEROX CORPORATION THAT OPERATES AT 10 MBPS USING CARRIER SENSE MULTIPLE ACCESS COLLISION DETECT (CSMA/CD) TO RUN OVER COAXIAL CABLE. ETHERNET WAS CREATED BY XEROX IN THE 1970 S, BUT THE TERM IS NOW OFTEN USED TO REFER TO ALL CSMA/CD LANS. ETHERNET WAS DESIGNED TO SERVE IN NETWORKS WITH SPORADIC, OCCASIONALLY HEAVY TRAFFIC REQUIREMENTS, AND THE IEEE 802. 3 SPECIFICATION WAS DEVELOPED IN 1980 BASED ON THE ORIGINAL ETHERNET TECHNOLOGY. ETHERNET VERSION 2. 0 WAS JOINTLY DEVELOPED BY DIGITAL EQUIPMENT CORPORATION, INTEL CORPORATION, AND XEROX CORPORATION. IT IS COMPATIBLE WITH IEEE 802. 3

IEEE 802. 3 COMPONENTS ARE NAMED ACCORDING TO CONVENTIONS

ETHERNET IMPLEMENTATIONS • 10 BASE 5 (THICK ETHERNET OR THICKNET) • LEADS TO STATIONS ARE TAPPED INTO UP TO 500 M OF THICK COAXIAL CABLE • 10 BASE 2 (THIN ETHERNET OR THINNET, CHEAPNET OR CHEAPERNET) • LEADS TO STATIONS ARE CONNECTED TO A THIN COAXIAL CABLE BUS OF UP TO 200 M VIA A THREE-WAY CONNECTOR • 10 BASE-T (TWISTED PAIR ETHERNET) • EACH STATION IS WIRED TO A HUB VIA TWISTED PAIR CABLE. THE HUB BROADCASTS FRAMES TO ALL STATIONS APART FROM THE ONE FROM WHICH IT RECEIVED THE FRAME • TOPOLOGY IS PHYSICALLY A STAR, BUT LOGICALLY A BUS

ETHERNET IMPLEMENTATIONS 10 Base 5 10 Base 2 10 Base-T © Tanenbaum, Prentice Hall International Note: the 1 st part of the name indicates the speed in Mbit/s, the 2 nd part whether it is baseband or broadband the final part the maximum distance the signals will carry in 100 s of meters or the type of media

COMPARISON OF VARIOUS IEEE 802. 3 PHYSICAL-LAYER SPECIFICATIONS

IEEE 802. 3 SPECIFICATION • ACCESS METHOD • CSMA/CD • BACKOFF ALGORITHM • BINARY EXPONENTIAL BACK-OFF • AFTER N COLLISIONS A RANDOM NUMBER BETWEEN 0 AND 2 N-1 IS CHOSEN AND TRANSMITTER BACKS OFF FOR THIS NUMBER OF TIMESLOTS (TIMESLOT = WORST CASE RTT = 51. 2 MICROSECONDS AT 10 MBIT/S) • AFTER 10 COLLISIONS MAXIMUM BACKOFF TIME FROZEN • AFTER 16 COLLISIONS ALGORITHM GIVES UP • HENCE DELAY IS VARIABLE AND THERE IS NO GUARANTEE THAT THE FRAME WILL EVER BE TRANSMITTED

ETHERNET OPERATES IN THE DATA LINK LAYER AND THE PHYSICAL LAYER. IT IS A FAMILY OF NETWORKING TECHNOLOGIES THAT ARE DEFINED IN THE IEEE 802. 2 AND 802. 3 STANDARDS. ETHERNET SUPPORTS DATA BANDWIDTHS OF: • 10 MB/S, 1000 MB/S (1 GB/S) • 10, 000 MB/S (10 GB/S), 40, 000 MB/S (40 GB/S) • 100, 000 MB/S (100 GB/S) IN FIGURE , ETHERNET STANDARDS DEFINE BOTH THE LAYER 2 PROTOCOLS AND THE LAYER 1 TECHNOLOGIES. FOR THE LAYER 2 PROTOCOLS, AS WITH ALL 802 IEEE STANDARDS, ETHERNET RELIES ON THE TWO SEPARATE SUBLAYERS OF THE DATA LINK LAYER TO OPERATE, THE LOGICAL LINK CONTROL (LLC) AND THE MAC SUBLAYERS.

ETHERNET ENCAPSULATION

MAC SUBLAYER MEDIA ACCESS CONTROL • THE SECOND RESPONSIBILITY OF THE MAC SUBLAYER IS MEDIA ACCESS CONTROL IS RESPONSIBLE FOR THE PLACEMENT OF FRAMES ON THE MEDIA AND THE REMOVAL OF FRAMES FROM THE MEDIA. AS ITS NAME IMPLIES, IT CONTROLS ACCESS TO THE MEDIA. THIS SUBLAYER COMMUNICATES DIRECTLY WITH THE PHYSICAL LAYER.

MEDIUM ACCESS CONTROL (MAC) • TRADITIONALLY, IN LANS DATA IS BROADCAST • THERE IS A SINGLE MEDIUM SHARED BY DIFFERENT USERS • WE NEED MAC SUBLAYER FOR • ORDERLY AND EFFICIENT USE OF BROADCAST MEDIUM • THIS IS ACTUALLY A “CHANNEL ALLOCATION” PROBLEM • SYNCHRONOUS (STATIC) SOLUTIONS • EVERYONE KNOWS WHEN TO TRANSMIT • ASYNCHRONOUS (DYNAMIC) SOLUTION • IN RESPONSE TO IMMEDIATE NEEDS • TWO CATEGORIES • ROUND ROBIN • CONTENTION

STATIC CHANNEL ALLOCATION • FREQUENCY DIVISION MULTIPLEXING (FDM) • CHANNEL IS DIVIDED TO CARRY DIFFERENT SIGNALS AT DIFFERENT FREQUENCIES • EFFICIENT IF THERE IS A CONSTANT (ONE FOR EACH SLOT) AMOUNT OF USERS WITH CONTINOUS TRAFFIC • PROBLEMATIC IF THERE ARE LESS OR MORE USERS • EVEN IF THE AMOUNT OF USERS = # OF CHANNELS, UTILIZATION IS STILL LOW SINCE TYPICAL NETWORK TRAFFIC IS NOT UNIFORM AND SOME USERS MAY NOT HAVE

STATIC CHANNEL ALLOCATION • TIME DIVISION MULTIPLEXING • EACH USER IS STATICALLY ALLOCATED ONE TIME SLOT • IF A PARTICULAR USER DOES NOT HAVE ANYTHING TO SEND, IT REMAINS IDLE AND WASTES THE CHANNEL FOR THAT PERIOD • A USER MAY NOT UTILIZE THE WHOLE CHANNEL FOR A TIME SLOT • THUS, INEFFICIENT.

DYNAMIC CHANNEL ALLOCATION CATEGORIES • ROUND ROBIN • EACH STATION HAS A TURN TO TRANSMIT • DECLINES OR TRANSMITS UP TO A CERTAIN DATA LIMIT • OVERHEAD OF PASSING THE TURN IN EITHER CASE • PERFORMS WELL IF MANY STATIONS HAVE DATA TO TRANSMIT FOR MOST OF THE TIME • OTHERWISE PASSING THE TURN WOULD CAUSE INEFFICIENCY

CSMA (CARRIER SENSE MULTIPLE ACCESS) • FIRST LISTEN FOR CLEAR MEDIUM (CARRIER SENSE) • IF MEDIUM IDLE, TRANSMIT • IF BUSY, CONTINUOUSLY CHECK THE CHANNEL UNTIL IT IS IDLE AND THEN TRANSMIT • IF COLLISION OCCURS • WAIT RANDOM TIME AND RETRANSMIT (CALLED BACK-OFF ) • COLLISION PROBABILITY DEPENDS ON THE PROPAGATION DELAY • LONGER PROPAGATION DELAY, WORSE THE UTILIZATION • COLLISION MAY OCCUR EVEN IF THE PROPAGATION TIME IS ZERO. • WHY? • 1 -PERSISTENT CSMA • BETTER UTILIZATION THAN ALOHA

BINARY EXPONENTIAL BACK OFF • RANDOM WAITING PERIOD BUT CONSECUTIVE COLLISIONS INCREASE THE MEAN WAITING TIME • • • MEAN WAITING TIME DOUBLES IN THE FIRST 10 RETRANSMISSION ATTEMPTS AFTER FIRST COLLISION, WAITS 0 OR 1 SLOT TIME (SELECTED AT RANDOM) IF COLLIDED AGAIN (SECOND TIME), WAITS 0, 1, 2 OR 3 SLOTS (AT RANDOM) IF COLLIDED FOR THE ITH TIME, WAITS 0, 1, …, OR 2 I-1 SLOTS (AT RANDOM) THE RANDOMIZATION INTERVAL IS FIXED TO 0 … 1023 AFTER 10 TH COLLISION STATION TRIES A TOTAL OF 16 TIMES AND THEN GIVES UP IF CANNOT TRANSMIT • LOW DELAY WITH SMALL AMOUNT OF WAITING STATIONS • LARGE DELAY WITH LARGE AMOUNT OF WAITING STATIONS one slot time = max. round trip delay 50 microsecs in 10 Mbps Ethernet (see next slide for details of this value)

CSMA/CD

ETHERNET EVOLUTION

ETHERNET PROTOCOL • MAC ADDRESSES AND HEXADECIMAL • FRAME PROCESSING • MAC ADDRESS IS 48 -BIT LONG AND EXPRESSED AS 12 HEXADECIMAL DIGITS. • THE NIC COMPARES THE DESTINATION MAC ADDRESS IN THE FRAME WITH THE DEVICE’S PHYSICAL MAC ADDRESS STORED IN RAM. • MAC ADDRESSES: ETHERNET IDENTITY • • IEEE REQUIRES A VENDOR TO FOLLOW TWO SIMPLE RULES: IF THERE IS A MATCH, THE FRAMED IS PASSED UP THE OSI LAYERS. • IF THERE IS NO MATCH, THE DEVICE DISCARDS THE FRAME. • MAC ADDRESS REPRESENTATIONS • MAC ADDRESSES CAN BE REPRESENTED WITH COLONS, DASHES OR DOTS AND ARE CASE-INSENSITIVE. • 00 -60 -2 F-3 A-07 -BC, 00: 60: 2 F: 3 A: 07: BC, 0060. 2 F 3 A. 07 BC AND 0060 -2 F-3 A-07 -BC ARE ALL VALID REPRESENTATIONS OF THE SAME MAC ADDRESS. • MUST USE THAT VENDOR'S ASSIGNED OUI AS THE FIRST THREE BYTES. • ALL MAC ADDRESSES WITH THE SAME OUI MUST BE ASSIGNED A UNIQUE VALUE IN THE LAST THREE BYTES.

ETHERNET PROTOCOL • UNICAST MAC ADDRESS • UNIQUE ADDRESS USED WHEN A FRAME IS SENT FROM A SINGLE TRANSMITTING DEVICE TO A SINGLE DESTINATION DEVICE. • THE SOURCE MAC ADDRESS MUST ALWAYS BE A UNICAST. • BROADCAST MAC ADDRESS • USED TO ADDRESS ALL NODES IN THE SEGMENT. • THE DESTINATION MAC ADDRESS IS THE ADDRESS OF FF-FF-FF-FF IN HEXADECIMAL (48 ONES IN BINARY). • MULTICAST MAC ADDRESS • USED TO ADDRESS A GROUP OF NODES IN THE SEGMENT. • THE MULTICAST MAC ADDRESS IS A SPECIAL VALUE THAT BEGINS WITH 01 -00 -5 E IN HEXADECIMAL. • THE REMAINING PORTION OF THE MULTICAST MAC ADDRESS IS CREATED BY CONVERTING THE LOWER 23 BITS OF THE IP MULTICAST GROUP ADDRESS INTO 6 HEXADECIMAL CHARACTERS.

10 -MBPS ETHERNET • 10 BASE 5, 10 BASE 2, AND 10 BASE-T ETHERNET ARE CONSIDERED LEGACY ETHERNET. • ALL SHARE THE SAME TIMING PARAMETERS • ALL HAVE A COMMON FRAME FORMAT. Parameter Value Bit time 100 ns Slot time 512 bit times Interframe Spacing 96 bit (9, 6 us) Collision attempt limit 16 Collision Backoff limit 10 Collision Jam Size 32 bit Maximum Frame Size 1518 byte Minimum Frame Size 64 byte Manchester Line Code • ALL USE 'MANCHESTER' LINE CODING ON THE PHYSICAL LAYER. THIS LINE CODE IS ESPECIALLY USEFUL IN CARRYING THE CLOCK SIGNAL FROM THE TRANSMITTER TO THE RETIMING CIRCUIT IN THE RECEIVER • 10 BASE 5 (1980; 500 M) AND 10 BASE 2 (1985; 185 M; <=30 STATIONS/SEGMENT) ONLY RUN IN HALF-DUPLEX MODE. 5 -4 -3 -RULE IS OBLIGED. BOTH ARE NOT RECOMMENDED FOR INSTALLATIONS IN NETWORKS TODAY.

ETHERNET MAC ADDRESS STRUCTURE • IN ETHERNET, EVERY NETWORK DEVICE IS CONNECTED TO THE SAME, SHARED MEDIA. ETHERNET WAS ONCE PREDOMINANTLY A HALFDUPLEX TOPOLOGY USING A MULTI-ACCESS BUS OR LATER ETHERNET HUBS. THIS MEANT THAT ALL NODES WOULD RECEIVE EVERY FRAME TRANSMITTED. TO PREVENT THE EXCESSIVE OVERHEAD INVOLVED IN THE PROCESSING OF EVERY FRAME, MAC ADDRESSES WERE CREATED TO IDENTIFY THE ACTUAL SOURCE AND DESTINATION. MAC ADDRESSING PROVIDES A METHOD FOR DEVICE IDENTIFICATION AT THE LOWER LEVEL OF THE OSI MODEL.

FRAME FORWARD

UNICAST

BROADCAST

MULTICAST

IEEE 802. 3 U, IEEE 802. 3 Z, IEEE 802. 3 AE

BACKBONE LAN STANDARDS • IEEE 802. 3 U (FAST ETHERNET – 100 MBIT/S) • IEEE 802. 3 Z (GIGABIT ETHERNET – 1000 MBIT/S) • IEE 802. 3 AE (10 G ETHERNET – 10 GBIT/S) • ANSI X 3 TP. 5 (FIBRE DISTRIBUTED DATA INTERFACE - FDDI)

IEEE 802. 3 U (FAST ETHERNET) IMPLEMENTATIONS • 100 BASE-TX • USES 2 CAT 5 UTP OR 2 STP CABLES UP TO 100 M TO HUB OR SWITCH WITH 4 B/5 B ENCODING AND NRZ-I SIGNALLING • 100 BASE-FX • USES 2 OPTICAL FIBRES UP TO 2000 M TO HUB OR SWITCH WITH 4 B/5 B ENCODING AND NRZ-I SIGNALLING • 100 BASE-T 4 • USES 4 CAT 3 UTP CABLES UP TO 100 M TO HUB OR SWITCH BY SPLITTING THE 100 MBIT/S CAPACITY INTO 3 X 33. 66 MBIT/S CHANNELS

FAST ETHERNET - DETAILS • SAME MESSAGE FORMAT AS 10 MBPS ETHERNET • FAST ETHERNET MAY RUN IN FULL DUPLEX MODE • SO EFFECTIVE DATA RATE PER USER BECOMES 200 MBPS • FULL DUPLEX MODE REQUIRES STAR TOPOLOGY WITH SWITCHES • IN FACT, SHARED MEDIUM NO LONGER EXISTS WHEN SWITCHES ARE USED • NO COLLISIONS, THUS CSMA/CD ALGORITHM NO LONGER NEEDED • BUT STATIONS STILL USE CSMA/CD AND SAME MESSAGE FORMAT IS USED FOR BACKWARD COMPATIBILITY REASONS

100 -MBPS ETHERNET • 100 -MBPS ETHERNET IS ALSO KNOWN AS FAST ETHERNET. • 100 BASE-T (1995) USES A COPPER UTP MEDIUM AND 100 BASE-FX USES A MULTIMODE OPTICAL FIBER MEDIUM. • COMMON CHARACTERISTICS OF 100 BASE-T AND 100 BASEFX: • TIMING PARAMETERS • FRAME FORMAT, AND • PARTS OF THE TRANSMISSION PROCESS. • 100 BASE-T CARRIES 100 MBPS OF TRAFFIC IN HALFDUPLEX MODE. IN FULL-DUPLEX MODE, 100 BASE-T CAN EXCHANGE 200 MBPS OF TRAFFIC. • FAST ETHERNET USES A 2 STEP LINE ENCODING SCHEME: • FIRST A 4 B/5 B LINE CODING IS USED BY T AND FX TECHNOLOGY. THIS CODING SCHEME PROVIDES SUFFICIENT CLOCKING INFORMATION FOR THE RECEIVER AT THE EXPENSE OF INCREASING THE BANDWIDTH FROM 100 MBAUD UP TO 125 MBAUD. IN CONTRAST, MANCHESTER CODE WOULD REQUIRE 200 MBAUD BANDWIDTH. • SECOND, 100 BASE-T USES MULTI-LEVEL TRANSMIT-3 LEVELS MLT-3 ENCODING AND FX USES NRZI ENCODING OF THE 4 B 5 B CODED BIT STREAM. Non-Return-to-Zero (NRZ): 0 kein Signal; 1 +Signal Manchester-Code: 1 +|- Signal 0 -|+ Signal NRZ-I: 0 kein Signalwechsel 1 Signalwechsel Multi-Level-Transition-3 (MLT-3): 1 Signalwechsel in Folgezustand (1111 +1|0|-1|0) 0 kein Signalwechsel MLT-3 coding requires 1 Hz of bandwidth per 4 symbol times. For 125 Mbaud ( 1 baud = 1 symbol per second) MLT-3 needs 31, 25 MHz bandwidth.

GIGABIT ETHERNET • STRATEGY SAME AS FAST ETHERNET • NEW MEDIUM AND TRANSMISSION SPECIFICATION • RETAINS CSMA/CD PROTOCOL AND FRAME FORMAT • COMPATIBLE WITH 10 AND 100 MBPS ETHERNET • WHY GIGABIT ETHERNET? • 10/100 MBPS LOAD FROM END USERS CREATES INCREASED TRAFFIC ON BACKBONES • SO GIGABIT ETHERNET IS MEANINGFUL FOR BACKBONES

IEEE 802. 3 Z (GIGABIT ETHERNET) IMPLEMENTATIONS • 1000 BASE-SX • MULTI-MODE OPTICAL FIBRE WITH SHORT WAVE LASERS UP TO 550 M • 1000 BASE-LX • MULTI-MODE OR SINGLE-MODE OPTICAL FIBRE WITH LONG WAVE LASER UP TO 550 M (MULTI-MODE) OR 5000 M (SINGLEMODE) • 1000 BASE-CX • SHIELDED TWISTED PAIR UP TO 25 M • 1000 BASE-T • UNSHIELDED TWISTED PAIR UP TO 25 M

1000 -MBPS ETHERNET • 1000 BASE-T (IEEE 802. 3 AB), 1000 BASE-SX, AND 1000 BASE-LX (IEEE 802. 3 Z) USE THE SAME TIMING PARAMETERS, AS SHOWN IN THE TABLE. • ONE OF THE MOST IMPORTANT ATTRIBUTES OF THE 1000 BASE-T STANDARD IS THAT IT BE INTEROPERABLE WITH 10 BASE-T AND 100 BASE-T. IT REQUIRES THE CABLING TO PASS THE CAT-5 E TEST. • THE GIGABIT ETHERNET FRAME HAS THE SAME FORMAT AS IS USED FOR 10 - AND 100 MBPS ETHERNET. • THE DIFFERENCES BETWEEN STANDARD ETHERNET, FAST ETHERNET AND GIGABIT ETHERNET OCCUR AT THE PHYSICAL LAYER. • FIBER-BASED GIGABIT ETHERNET (1000 BASEX) USES 8 B/10 B ENCODING WHICH IS SIMILAR TO THE 4 B/5 B CONCEPT. THIS IS FOLLOWED BY THE SIMPLE NON-RETURN TO ZERO (NRZ) LINE ENCODING OF LIGHT ON OPTICAL FIBER. • GIGABIT ETHERNET IS REQUIRED TO OPERATE WITH A BIT ERROR RATE (BER) OF ≤ 10 -10 Parameter Value Bit time 1 ns Slot time 4096 bit times Interframe Spacing 96 bit Collision attempt limit 16 Collision Backoff limit 10 Collision Jam Size 32 bit Maximum Frame Size 1518 byte Minimum Frame Size 64 byte

1000 BASE-T BANDWIDTH REQUIREMENTS START WITH 1000 MBIT/S 1. USE ALL 4 CIRCUITS FULL DUPLEX • 250 MBPS PER CIRCUIT IN BOTH DIRECTIONS • REQUIRES ECHO AND NEXT CANCELLING • REQUIRES MASTER/SLAVE CLOCKING 2. 5 LEVEL SIGNALLING – 2 BITS/SYMBOL REQUIRES 4 LEVELS - THE REMAINING 5 TH LEVEL SUPPORTS FEC • PULSE AMPLITUDE MODULATION 5 (PAM 5) IS USED ON CAT 5 E (UTP) • 125 MBAUD PER CIRCUIT IN BOTH DIRECTIONS REQUIRES 72, 5 MHZ CIRCUIT BANDWIDTH • REQUIRES FEC TO GET BACK THE 6 DB SNR

GIGABIT ETHERNET MEDIUM OPTIONS (LOG SCALE)

10 GBPS ETHERNET • WHY? • SAME REASONS: INCREASE IN TRAFFIC, MULTIMEDIA COMMUNICATIONS. ETC. • PRIMARILY FOR HIGH-SPEED, LOCAL BACKBONE INTERCONNECTION BETWEEN LARGECAPACITY SWITCHES • ALLOWS CONSTRUCTION OF MANS • CONNECT GEOGRAPHICALLY DISPERSED LANS • VARIETY OF STANDARD OPTICAL INTERFACES (WAVELENGTHS AND LINK DISTANCES) SPECIFIED FOR 10 GB ETHERNET • 300 M TO 40 KMS • FULL DUPLEX

EXAMPLE 10 GIGABIT ETHERNET CONFIGURATION

10 -GIGABIT ETHERNET • IEEE 802. 3 AE (JUNE 2002) INCLUDES 10 GBPS FULL-DUPLEX TRANSMISSION OVER FIBER OPTIC CABLE. • THIS 10 -GIGABIT ETHERNET (10 GBE) IS EVOLVING FOR NOT ONLY LANS, BUT ALSO MANS, AND WANS. • 10 GBE PHYSICAL LAYER STANDARDS ALLOW BOTH AN EXTENSION IN DISTANCE TO 40 KM OVER SINGLE-MODE FIBER AND COMPATIBILITY WITH SYNCHRONOUS OPTICAL NETWORK (SONET) AND SYNCHRONOUS DIGITAL HIERARCHY (SDH) NETWORKS. Parameter Value Bit time 0. 1 ns Slot time na Interframe Spacing Collision attempt limit Collision Backoff limit Collision Jam Size Maximum Frame Size Minimum Frame Size Burst Limit 65536 bits • HOW DOES 10 GBE COMPARE TO OTHER VARIETIES OF ETHERNET? 96 bit na na na 1518 byte 64 byte • FRAME FORMAT IS THE SAME, ALLOWING INTEROPERABILITY BETWEEN ALL VARIETIES OF LEGACY, FAST, GIGABIT, AND 10 GIGABIT, WITH NO REFRAMING OR PROTOCOL CONVERSIONS. • BIT TIME IS NOW 0. 1 NS. ALL OTHER TIME VARIABLES SCALE ACCORDINGLY. • ONLY FULL-DUPLEX FIBER CONNECTIONS ARE USED. CSMA/CD IS NOT NECESSARY • THE IEEE 802. 3 SUBLAYERS WITHIN OSI LAYERS 1 AND 2 ARE MOSTLY PRESERVED, WITH A FEW ADDITIONS TO ACCOMMODATE 40 KM FIBER LINKS AND INTEROPERABILITY WITH SONET/SDH TECHNOLOGIES. • FLEXIBLE, EFFICIENT, RELIABLE, RELATIVELY LOW COST END-TO-END ETHERNET NETWORKS BECOME POSSIBLE.

10 -GIGABIT ETHERNET VARIANTS • A VARIETY OF IMPLEMENTATIONS ARE BEING CONSIDERED WITH 10 GBE, INCLUDING: • 10 GBASE-SR – INTENDED FOR SHORT DISTANCES OVER ALREADY-INSTALLED MULTIMODE FIBER, SUPPORTS A RANGE BETWEEN 26 M TO 82 M • 10 GBASE-LX 4 – USES WAVELENGTH DIVISION MULTIPLEXING (WDM), SUPPORTS 240 M TO 300 M OVER ALREADY-INSTALLED MULTIMODE FIBER AND 10 KM OVER SINGLE-MODE FIBER • 10 GBASE-LR AND 10 GBASE-ER – SUPPORT 10 KM AND 40 KM OVER SINGLE-MODE FIBER • 10 GBASE-SW, 10 GBASE-LW, AND 10 GBASE-EW – KNOWN COLLECTIVELY AS 10 GBASEW ARE INTENDED TO WORK WITH OC-192 SYNCHRONOUS TRANSPORT MODULE (STM) SONET/SDH WAN EQUIPMENT.

10 -GIGABIT ETHERNET ARCHITECTURES • 10 GBASE-LX 4, WHICH USES WIDE WAVELENGTH DIVISION MULTIPLEX (WWDM) TO MULTIPLEX FOUR BIT-SIMULTANEOUS BIT STREAMS AS FOUR WAVELENGTHS OF LIGHT LAUNCHED INTO THE FIBER AT ONE TIME. • CURRENTLY, MOST 10 GBE PRODUCTS ARE IN THE FORM OF MODULES, OR LINE CARDS, FOR ADDITION TO HIGH-END SWITCHES AND ROUTERS. • NO REPEATER IS DEFINED FOR 10 -GIGABIT ETHERNET 51

10 -GBPS ETHERNET DATA RATE AND DISTANCE OPTIONS (LOG SCALE) We also have copper alternatives. 10 GBASE-T uses Cat 6 up to 55 m; Cat 6 a (augmented Cat 6) up to 100 m. Special encoding is used

10 -GIGABIT AND UP • IEEE STANDARDS • 802. 3 AE 10 GBE OVER FIBER • 802. 3 AK 10 GBE OVER TWIN AXIAL CABLE (10 GBASE-CX 4) • 802. 3 AN 10 GBE OVER UTP (10 GBASE-T) • 802. 3 BA 40 GBE AND 100 GBE 53

FIBRE DISTRIBUTED DATA INTERFACE (FDDI) • FDDI IS A HIGH PERFORMANCE LAN PROTOCOL FOR USE OVER OPTICAL FIBRES STANDARDISED BY ANSI AND ITU-T • THE TOPOLOGY IS BASE ON TWO RINGS WITH DATA FLOWING IN OPPOSITE DIRECTIONS • IF THERE IS A BREAK IN THE CABLE, THE STATIONS EITHER SIDE OF THE BREAK DETECT IT AND SIMPLY LOOP THE CABLES TO FORM ONE RING • AS WITH TOKEN RINGS, THE FDDI RING CAN BE COLLAPSED INTO A WIRE CENTRE TO FURTHER PROTECT AGAINST CABLE FAILURES BRINGING THE NETWORK DOWN

FDDI DUAL RING BACK-UP Cable Break

FDDI PROTOCOL • ACCESS METHOD • TOKEN PASSING • ELECTRICAL • BASEBAND WITH 4 B/5 B (4 BITS ARE REPRESENTED BY 5 BITS CONTAINING NO MORE THAN TWO CONSECUTIVE ZEROS) ENCODING WITH NRZ-I SIGNALING • DATA RATES • 100 MBIT/S • ADDRESSING • MAC ADDRESSES BURNT INTO NETWORK INTERFACE CARDS

EVOLUTION OF ETHERNET STANDARDS IN IEEE 802. 3

SPEED AND REACH FOR VARIOUS IEEE STD 802. 3 MAUS AND PHYS

OPTICAL P 2 MP LINKS AND EVOLUTION OF EPON

NG-EPON OLT SUPPORTING MULTIPLE NG-EPON ONUS

EPON PROTOCOL OVER COAX: BRINGING THE COPPER AND OPTICAL WORLDS TOGETHER

SUMMARY • THE WORK WITHIN THE IEEE 802. 3 WORKING GROUP IS FAR FROM DONE, WITH THE NEXT GENERATION OF HIGH-SPEED 40/100/200/400 G LINKS AIMING FOR BROADER MARKET ADOPTION THROUGH INCREASING THE COST-EFFECTIVENESS OF SOLUTIONS WHILE DECREASING THE POWER CONSUMPTION AND COMPLEXITY OF COMPATIBLE PRODUCTS. THIS WORK ALSO FOCUSES ON LOWER SPEEDS. THE 10 MB/S EXTENDED REACH SINGLE TWISTED PAIR ETHERNET PHY (HTTP: //WWW. IEEE 802. ORG/3/CFI/REQUEST_0716_1. HTML) PROJECT, AIMS TO ADDRESS EXISTING MARKET DEMAND FOR A UNIFIED LOWER SPEED AND A LONGER-REACH PHY FOR AUTOMATION PURPOSES. THE IEEE 802. 3 WORKING GROUP IS THUS LOOKING FOR WAYS TO EXPAND ETHERNET MARKET COVERAGE AND TO SUPPORT HIGHER DATA RATES WHILE ALSO PROVIDING COVERAGE FOR EMERGING MARKETS SUCH AS THE AUTOMOTIVE INDUSTRY. • IT CAN BE EXPECTED THAT INNOVATION IN THE AREA OF WIRED ETHERNET WILL CONTINUE IN THE YEARS TO COME, BRINGING THE SAME HIGHLY RELIABLE AND WELL-UNDERSTOOD NETWORKING PHILOSOPHY TO NEW MARKETS, ENABLING NEW APPLICATIONS, AND MAKING NETWORKING IN GENERAL MORE UBIQUITOUS.

IEEE 802. 11 WIRELESS LAN

THE OBJECTIVES • IEEE 802. 11 STANDAND • WLAN ARCHITECTURE • IEEE 802. 11 MEDIUM ACCESS CONTROL • WLAN TRANSMISSION TECHNOLOGY • IEEE 802. 11 SECURITY

INTRODUCTION TO IEEE 802. 11

IEEE 802. 11 INTRODUCTION • IEEE 802. 11 IS A WORKING GROUP, RESPONSIBLE FOR WRITING WIRELESS LOCAL AREA NETWORK (LAN) STANDARDS • 802. 11 OPERATES UNDER • THE “SPONSOR”: IEEE LMSC “LAN / MAN STANDARDS COMMITTEE” – AKA “ 802” • IEEE COMPUTER SOCIETY • IEEE-SA STANDARDS BOARD • WORK IN 802. 11 IS DIVIDED INTO VARIOUS ACTIVITIES • TASK GROUPS – ONE PER APPROVED STANDARD OR AMENDMENT TO BE DEVELOPED • STUDY GROUPS OR TOPIC INTEREST GROUPS – THE PRECURSOR TO A TASK GROUP THAT INVESTIGATES MARKETABILITY, FEASIBILITY AND DETERMINES INITIAL REQUIREMENTS • VARIOUS STANDING COMMITTEE'S RESPONSIBLE FOR ONGOING WORK, SUCH AS “ARCHITECTURE”

IEEE 802. 11 SCOPE • WIRELESS LOCAL AREA NETWORKS • TYPICAL RANGE UP TO 100 M • GENERALLY USE UNLICENSED SPECTRUM • EXCEPTION FOR 802. 11 Y: “LIGHTLY LICENSED” • EXCEPTION FOR TV WHITESPACE • DEPLOYMENTS: BROADBAND NETWORK ACCESS, PUBLIC VENUE ACCESS, SENSOR NETWORKS, MESH NETWORKS, AUTOMOTIVE. • PRESENT IN THESE DEVICES: LAPTOPS, PHONES, TABLETS, NETWORK INFRASTRUCTURE, HOME APPLIANCES, CONSUMER ELECTRONICS, HEALTHCARE DEVICES

IEEE 802. 11 REVISIONS MAC 11 d Intl roaming IEEE Std 802. 11 -1997 11 e Qo. S 11 k RRM 11 s Mesh 11 h DFS & TPC 11 u WIEN 11 v Network Management 11 i Security 11 f Inter AP 11 z TDLS 11 r Fast Roam 11 aa Video Transport 11 ae Qo. S Mgt Frames 11 w Management Frame Security 802. 11 -2016 (TBC) 802. 11 -2003 802. 11 -2007 802. 11 -2012 11 a 54 Mbps 5 GHz 11 j JP bands 11 n High Throughput (>100 Mbps) 11 af TV Whitespace 11 ac -VHT >1 Gbps @ 5 GHz 11 b 11 Mbps 2. 4 GHz MAC & PHY 11 g 54 Mbps 2. 4 GHz 11 p WAVE 11 y Contention Based Protocol 11 ad - VHT >1 Gbps @ 60 GHz

IEEE 802. 11 STANDARDS PIPELINE MAC 802. 11 aq PAD 802. 11 -2016 802. 11 aa Video Transport 802. 11 ak GLK WNG LRLP TIG Long Range Low Power 802. 11 ai FILS 802. 11 az NGP 802. 11 ah < 1 Ghz 802. 11 ax HEW Discussion Topics 802. 11 ad VHT 60 GHz 802. 11 aj CMMW TIG/Study groups TG without Approved draft 802. 11 af TVWS 802. 11 -2012 802. 11 ac VHT 5 GHz 802. 11 ay NG 60 MAC & PHY 802. 11 ae Qo. S Mgt Frames WG Letter Ballot Sponsor Ballot Published Amendment Published Standard

100 Gbps PHY PROJECT SEQUENCE 10 year yardstick 10 Gbps 1 Gbps 802. 3 100 Mbps 10 Mbps 802. 11 1 Mbps 100 Kbps 80 85 90 95 00 05 10 15

802. 11 ARCHITECTURE OVERVIEW • MULTIPLE OVER THE AIR PHY OPTIONS • ONE COMMON MAC BASED ON CSMA/CA a b g n ac 802. 11 MAC 02 Sept 2015 ad af ah ax

SUMMARY OF COMPLETED MAJOR MAC PROJECTS • D – COUNTRY INFORMATION • AA – VIDEO TRANSPORT • E - QOS • AC – VERY HIGH THROUGHPUT (<6 GHZ) • F – INTER AP COMMUNICATION • AD – VERY HIGH THROUGHPUT (60 GHZ) • H – DFS, TPC SPECTRUM SHARING WITH RADARS IN 5 GHZ • J – JAPAN SPECTRUM @ 4. 9 GHZ • K – RADIO MEASUREMENT • P – VEHICULAR ENVIRONMENTS • R – FAST ROAMING • S – MESH NETWORKING • U – INTER-NETWORKING • V – NETWORK MANAGEMENT • W – SECURE MANAGEMENT FRAMES • Z – TUNNELED DIRECT LINK • AE – QOS FOR MANAGEMENT FRAMES

IEEE 802. 11 WIRELESS LAN STANDARD • IN RESPONSE TO LACKING STANDARDS, IEEE DEVELOPED THE FIRST INTERNATIONALLY RECOGNIZED WIRELESS LAN STANDARD – IEEE 802. 11 • IEEE PUBLISHED 802. 11 IN 1997, AFTER SEVEN YEARS OF WORK • MOST PROMINENT SPECIFICATION FOR WLANS • SCOPE OF IEEE 802. 11 IS LIMITED TO PHYSICAL AND DATA LINK LAYERS.

BENEFITS OF 802. 11 STANDARD • APPLIANCE INTEROPERABILITY • FAST PRODUCT DEVELOPMENT • STABLE FUTURE MIGRATION • PRICE REDUCTIONS • THE 802. 11 STANDARD TAKES INTO ACCOUNT THE FOLLOWING SIGNIFICANT DIFFERENCES BETWEEN WIRELESS AND WIRED LANS: • POWER MANAGEMENT • SECURITY • BANDWIDTH

IEEE 802 LAN STANDARDS FAMILY IEEE 802. 2 Logical Link Control (LLC) IEEE 802. 3 Carrier Sense IEEE 802. 4 Token Bus IEEE 802. 5 IEEE 802. 11 Token Ring Wireless OSI Layer 2 (Data Link) Mac PHY OSI Layer 1 (Physical)

IEEE 802. 11 TERMINOLOGY • ACCESS POINT (AP): A STATION THAT PROVIDES ACCESS TO THE DS. • BASIC SERVICE SET (BSS): A SET OF STATIONS CONTROLLED BY A SINGLE AP. • DISTRIBUTION SYSTEM (DS): A SYSTEM USED TO INTERCONNECT A SET OF BSSS TO CREATE AN ESS. • DS IS IMPLEMENTATION-INDEPENDENT. IT CAN BE A WIRED 802. 3 ETHERNET LAN, 802. 4 TOKEN BUS, 802. 5 TOKEN RING OR ANOTHER 802. 11 MEDIUM. • EXTENDED SERVICE SET (ESS): TWO OR MORE BSS INTERCONNECTED BY DS • PORTAL: LOGICAL ENTITY WHERE 802. 11 NETWORK INTEGRATES WITH A NON 802. 11 NETWORK.

WLAN TOPOLOGY AD-HOC NETWORK

WLAN Topology Infrastructure

IEEE 802. 11 SERVICES: DISTRIBUTION OF MESSAGES • DISTRIBUTION SERVICE (DS) • USED TO EXCHANGE MAC FRAMES FROM STATION IN ONE BSS TO STATION IN ANOTHER BSS • INTEGRATION SERVICE • TRANSFER OF DATA BETWEEN STATION ON IEEE 802. 11 LAN AND STATION ON INTEGRATED IEEE 802. X LAN

A SCENARIO Internet AP #2 AP #1 (1) Associate move (1) Association (2) Reassociation (3) Disassociation Reassociate (2) Disassociate (3) leave

ASSOCIATION RELATED SERVICES • ASSOCIATION • ESTABLISHES INITIAL ASSOCIATION BETWEEN STATION AND AP • RE-ASSOCIATION • ENABLES TRANSFER OF ASSOCIATION FROM ONE AP TO ANOTHER, ALLOWING STATION TO MOVE FROM ONE BSS TO ANOTHER • DISASSOCIATION • ASSOCIATION TERMINATION NOTICE FROM STATION OR AP

RE-ASSOCIATION

ACCESS AND PRIVACY SERVICES • AUTHENTICATION • ESTABLISHES IDENTITY OF STATIONS TO EACH OTHER • DE-AUTHENTICATION • INVOKED WHEN EXISTING AUTHENTICATION IS TERMINATED • PRIVACY • PREVENTS MESSAGE CONTENTS FROM BEING READ BY UNINTENDED RECIPIENT

IEEE 802. 11 MEDIUM ACCESS CONTROL • MAC LAYER COVERS THREE FUNCTIONAL AREAS: • RELIABLE DATA DELIVERY • ACCESS CONTROL • SECURITY

RELIABLE DATA DELIVERY • LOSS OF FRAMES DUE TO NOISE, INTERFERENCE, AND PROPAGATION EFFECTS • FRAME EXCHANGE PROTOCOL • SOURCE STATION TRANSMITS DATA • DESTINATION RESPONDS WITH ACKNOWLEDGMENT (ACK) • IF SOURCE DOESN’T RECEIVE ACK, IT RETRANSMITS FRAME • FOUR FRAME EXCHANGE FOR ENHANCED RELIABILITY • SOURCE ISSUES REQUEST TO SEND (RTS) • DESTINATION RESPONDS WITH CLEAR TO SEND (CTS)

ACCESS CONTROL • DISTRIBUTED COORDINATION FUNCTION (DCF) • DISTRIBUTED ACCESS PROTOCOL • CONTENTION-BASED • MAKES USE OF CSMA/CA RATHER THAN CSMA/CD • SUITED FOR AD HOC NETWORK AND ORDINARY ASYNCHRONOUS TRAFFIC • POINT COORDINATION FUNCTION (PCF) • ALTERNATIVE ACCESS METHOD ON TOP OF DCF • CENTRALIZED ACCESS PROTOCOL • CONTENTION-FREE • WORKS LIKE POLLING • SUITED FOR TIME BOUND SERVICES LIKE VOICE OR MULTIMEDIA

CSMA/CD VS. CSMA/CA • CSMA/CD – CSMA/COLLISION DETECTION • FOR WIRE COMMUNICATION • NO CONTROL BEFORE TRANSMISSION • GENERATES COLLISIONS • COLLISION DETECTION-HOW? • CSMA/CA – CSMA/COLLISION AVOIDANCE • FOR WIRELESS COMMUNICATION • COLLISION AVOIDANCE BEFORE TRANSMISSION • WHY AVOIDANCE ON WIRELESS? • DIFFERENCE IN ENERGY/POWER FOR TRANSMIT & RECEIVE • DIFFICULT TO DISTINGUISH BETWEEN INCOMING WEAK SIGNALS, NOISE, AND EFFECTS OF OWN TRANSMISSION

INTERFRAME SPACE (IFS) • DEFINED LENGTH OF TIME FOR CONTROL • SIFS - SHORT INTER FRAME SPACING • USED FOR IMMEDIATE RESPONSE ACTIONS E. G ACK, CTS • PIFS - POINT INTER FRAME SPACING • USED BY CENTRALIZED CONTROLLER IN PCF SCHEME • DIFS - DISTRIBUTED INTER FRAME SPACING • USED FOR ALL ORDINARY ASYNCHRONOUS TRAFFIC • DIFS (MAX) > PIFS > SIFS (MIN)

RTS-CTS-DATA-ACK DIFS: Distributed IFS RTS: Request To Send SIFS: Short IFS CTS: Clear To Send ACK: Acknowledgement NAV: Network Allocation Vector DCF: Distributed Coordination Function

MAC FRAME FORMAT 2 2 Frame Control 6 Duration Addr 1 ID 6 6 Addr 2 2 6 Sequence Addr 4 Control Addr 3 0 -2312 4 Frame Body CRC 802. 11 MAC Header Bits: 2 Protocol Version 2 4 1 Type Sub. Type 1 1 To From More Pwr Retry Frag DS DS Mgt Frame Control Field 1 1 1 More WEP Order Data

MAC LAYER FRAMES • DATA FRAMES • CONTROL FRAMES • RTS, CTS, ACK AND PS-POLL • MANAGEMENT FRAMES • AUTHENTICATION AND DE-AUTHENTICATION • ASSOCIATION, RE-ASSOCIATION, AND DISASSOCIATION • BEACON AND PROBE FRAMES

IEEE 802. 11 SECURITY • AUTHENTICATION PROVIDED BY OPEN SYSTEM OR SHARED KEY AUTHENTICATION (AUTHENTICATION IS USED INSTEAD OF WIRED MEDIA PHYSICAL CONNECTION) • PRIVACY PROVIDED BY WEP (PRIVACY IS USED TO PROVIDE THE CONFIDENTIAL ASPECTS OF CLOSED WIRED MEDIA) • AN INTEGRITY CHECK IS PERFORMED USING A 32 -BIT CRC

AUTHENTICATION

WEP ENCRYPTION/DECRYPTION

IS WLAN SECURE ? • • • The Parking Lot attack Man in the middle attack Freely available tools like Air Snort, WEP crack to snoop into a WLAN Switch Router Switch Internet/ Intranet Access Point

PHYSICAL MEDIA DEFINED BY ORIGINAL 802. 11 STANDARD • FREQUENCY-HOPPING SPREAD SPECTRUM • OPERATING IN 2. 4 GHZ ISM BAND • LOWER COST, POWER CONSUMPTION • MOST TOLERANT TO SIGNAL INTERFERENCE • DIRECT-SEQUENCE SPREAD SPECTRUM • OPERATING IN 2. 4 GHZ ISM BAND • SUPPORTS HIGHER DATA RATES • MORE RANGE THAN FH OR IR PHYSICAL LAYERS • INFRARED • LOWEST COST • LOWEST RANGE COMPARED TO SPREAD

FREQUENCY HOPPING SPREAD SPECTRUM • SIGNAL IS BROADCAST OVER SEEMINGLY RANDOM SERIES OF RADIO FREQUENCIES • SIGNAL HOPS FROM FREQUENCY TO FREQUENCY AT FIXED INTERVALS • RECEIVER, HOPPING BETWEEN FREQUENCIES IN SYNCHRONIZATION WITH TRANSMITTER, PICKS UP MESSAGE • ADVANTAGES • EFFICIENT UTILIZATION OF AVAILABLE BANDWIDTH • EAVESDROPPER HEAR ONLY UNINTELLIGIBLE BLIPS • ATTEMPTS TO JAM SIGNAL ON ONE FREQUENCY SUCCEED ONLY AT KNOCKING OUT A FEW BITS

DIRECT SEQUENCE SPREAD SPECTRUM • EACH BIT IN ORIGINAL SIGNAL IS REPRESENTED BY MULTIPLE BITS IN THE TRANSMITTED SIGNAL • SPREADING CODE SPREADS SIGNAL ACROSS A WIDER FREQUENCY BAND • DSSS IS THE ONLY PHYSICAL LAYER SPECIFIED FOR THE 802. 11 B SPECIFICATION • 802. 11 A AND 802. 11 B DIFFER IN USE OF CHIPPING METHOD • 802. 11 A USES 11 -BIT BARKER CHIP • 802. 11 B USES 8 -BIT COMPLIMENTARY CODE KEYING (CCK) ALGORITHM

IEEE 802. 11 A AND IEEE 802. 11 B • IEEE 802. 11 A • MAKES USE OF 5 -GHZ BAND • PROVIDES RATES OF 6, 9 , 12, 18, 24, 36, 48, 54 MBPS • USES ORTHOGONAL FREQUENCY DIVISION MULTIPLEXING (OFDM) • IEEE 802. 11 B • 802. 11 B OPERATES IN 2. 4 GHZ BAND • PROVIDES DATA RATES OF 5. 5 AND 11 MBPS • COMPLEMENTARY CODE KEYING (CCK) MODULATION SCHEME

IEEE 802 WIRELESS

REFERENCE • CISCO CCNA • REINER NITSCH, FB INFORMATIK ETHERNET TECHNOLOGIES • PEOPLE. SABANCIUNIV. EDU (COMPUTER NETWORKS) • USE THE FOLLOWING WEB SITE TO EXPLAINE IEEE SHORTHAND IDENTIFIERS, SUCH AS 10 BASET, AND 100 BASET: HTTP: //COMPUTERNETWORKINGNOTES. COM/NETWORK-TECHNOLOGIES/10 BASE-ETHERNET. HTML • HTTP: //WWW. IEEE 802. ORG/3/BA/PUBLIC/INDEX. HTML • IEEE P 802. 3 BA 40 GB/S AND 100 GB/S ETHERNET TASK FORCE • WWW. IEEE 802. ORG • HTTPS: //WWW. STANDARDSUNIVERSITY. ORG/E-MAGAZINE/AUGUST-2016 -VOLUME-6 • POOJA MAHESHWARI, DR JERRY GAO WIRELESS LAN • ADRIAN STEPHENS, INTEL CORPORATION IEEE 802. 11 -17/355 R 0