1 it 327 - schweber chap 18 [the mother] of a young piano student, wishing to encourage him, bought...
TRANSCRIPT
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
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
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)
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
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