IT 327 - Schweber Chap 18 1

  

[The mother] of a young piano student, wishing to encourage him, bought tickets for a performance of the great Polish pianist, Paderewski. The night of the concert arrived and the mother and son found their seats near the front of the concert hall. While the mother visited with friends, the boy slipped quietly away.

Suddenly, it was time for the performance to begin and a single spotlight cut through the darkness of the concert hall to illuminate the grand piano on stage. Only then did the audience notice the little boy on the bench, innocently picking out “Twinkle, Twinkle, Little Star”.

His mother gasped, but before she could move, Paderewski appeared on stage and quickly moved to the keyboard. He whispered to the boy, “Don’t quit. Keep playing.” And then, leaning over, the master reached down with his left hand and began filling in the bass part. Soon his right arm reached around the other side, encircling the child, to add a running obbligato. Together, the old master and the young novice held the crowd mesmerized.

Thought of the Day

IT 327 - Schweber Chap 18 2

  

In our lives, unpolished though we may be, it is the Master who surrounds us and whispers in our ear, time and time again, “Don’t quit. Keep playing.” And as we do, He augments and supplements until a work of amazing beauty is created. He is right there with all of us, telling us over and over, “Keep playing.”

Pres. James E. Faust2nd Counselor, First Presidency

Nov 1999 Ensign, p. 101

Thought of the Day, cont’d

IT 327 - Schweber Chap 18 3

  

Gratitude is not only the greatest of virtues, but the parent of all the others.

Marcus Tullius Cicero

Thought of the Day

IT 327 - Schweber Chap 18 4

Schweber, Chap 18:Local and Wide Area Networks;

Special-Purpose Links

Networking: Topologies

IT 327 - Schweber Chap 18 5

One-to-All Star

Bus Ring

Networking: Topologies, cont’d

IT 327 - Schweber Chap 18 6

Networking: Protocols

IT 327 - Schweber Chap 18 7

Networking: Protocols

IT 327 - Schweber Chap 18 8

Networking: Tolkien Ring

IT 327 - Schweber Chap 18 9

Networking: Advanced Protocols

IT 327 - Schweber Chap 18 10

Property ISDN SONET FDDI ATM

Topology Bus Bus Ring Star

ProtocolLAPD (Link Access Protocol Ch D) SONET Token-passing

Specifies packets only

Modulation PCM (Pulse-Coded Modulation) & 2B1Q

PCM (Pulse-Coded Modulation) 5/4 encoding Varies

Data Rate(s)192 kbps (64k + 64k + 16k +48k)

OC-1 = 51.84 Mbps; also 3, 12, 48, 192, 768 (= 39.8 Gbps)

100 Mbps Varies

Typical Distance 2500-6500 m 100 km 100 km Varies

Cable Dual twisted pair Optical fiber Optical fiber Varies

Serial/Parallel Serial/Parallel Serial Serial Serial

Msg Length Variable 2,340 octets Variable Varies

Networking: The xANs

IT 327 - Schweber Chap 18 11

Designation Reach Media Typical Data Rate

PAN (Personal) 2 m Wireless 100 kbps

SAN (Sensor) 5 m Wireless 200 kbps

LAN (Local) 100 m CAT5/6 S/UTP 100 Mbps

EAN (Enterprise) 500 m Coaxial cable 200 Mbps

CAN (Campus) 2 km Coax/MMFiber 500 Mbps

MAN (Metropolitan) 20 km SMFiber 1 Gbps

WAN (Wide) 200-2000 km SMFiber 10-100 Gbps

Ethernet: High-Speed Stuff

IT 327 - Schweber Chap 18 12

Networking: The Stack (Layers)

IT 327 - Schweber Chap 18 13

Networking: The Stack (Layers)

IT 327 - Schweber Chap 18 14

Special Networks

IT 327 - Schweber Chap 18 15

Small Computers System Interface (SCSI) 50 Mbps, 1984; Ultra-5: 640 Mbps (2003) iSCSI: Ethernet/network dependent

Universal Serial Bus (USB) v. 1.0: 12 Mpbs; 1994; v. 2.0: 480 Mbps; 2000; v. 3.0: 4.8 Gbps

(2009) Firewire (IEEE 1394; AppleTalk)

400 Mbps; 1996; 800 Mbps (2006); declining Thunderbolt

10 Gbps; 4 lanes, differential, 5.4 Gbps/lane; 15 ft (5m) with copper; 100 m with MMF; Both PCI-e and DisplayPort

ATA (Advanced Technology Attachment 1064 Mbps over 16 parallel differential lines (40 conductors)

SATA (Serial ATA) 1.o = 1.5 Gbps over 2 paris; 2.0 = 3 Gbps; 3.0 = 6 Gbps (same

cable)

Networking: QoS

IT 327 - Schweber Chap 18 16

Networking: QoE

IT 327 - Schweber Chap 18 17

Spread-Spectrum Systems

IT 327 - Schweber Chap 18 18

Frequency-Hopping Spread Spectrum (FHSS)

Spread-Spectrum Systems

IT 327 - Schweber Chap 18 19

Direct-Sequence Spread Spectrum (DSSS)

Spread-Spectrum Systems

IT 327 - Schweber Chap 18 20

AdvantagesLooks like noiseCannot be received without key (PRBS pattern)Extremely difficult to jamCan accommodate n orthogonal signals & n*p

non-orthogonal signals, where p = degree of non-orthogonality (from >1 to 10 or more)

DisadvantagesVery complicated circuitry

Spread-Spectrum Systems & WiFi

IT 327 - Schweber Chap 18 21

Power Line Communications Primer

IT 327 - Schweber Chap 18 22

Developed over 40 years ago Major problems with

attenuation 10-30 dB/km on LV lines 100 dB/km on MV, HV lines Transformers even worse

Massive amounts of noise, both online and emitted

X10 uses ASK, 20 bps Modern systems use OFDM

HPAV (Home Plug AV) capable of 200 Mbps gross, 150 Mbps net; 500 Mbps and 1 Gbps expected

Turbo convolutional FEC MIMO (both “hot” and

“neutral”)

Power Line Communications Primer, p. 2

IT 327 - Schweber Chap 18 23

Apps in line metering, Smart Grid control, HANs

Other high-speed standards: HomePNA MoCA UPA (Spanish) G.hn (ITU standard) IEEE P1905 (interoper-ability

between Wi-Fi, Ethernet, MoCA)

Many NB (low speed) standards IEC 61334 IEEE 1901.2 HomePlug Green PHY G3 PRIME G.hnem

Common approaches: OFDM, 8PSK, DQPSK, RS FEC,

CRC

Shannon’s Law, Revisited

IT 327 - Schweber Chap 18 24

A ───→Noise=275 µW; Attenuation=46dB (wattage) ───→ BTx power = 50 dBm Find: 1. Rx power (mW)Tx channel = 964-972 MHz 2. Rx SNR (dB)

3. Capacity (Mbps)