Transcript ppt

ECEN5553 Telecom Systems
Dr. George Scheets
Week 10
[22] "The Great Spectrum Famine"
[23] "Spectrum Access Technologies:
The Past, the Present, and the Future"
[24a] "Meeting Mobile Demand with a Combination
of Spectrum Alternatives"
[24b] "The Multinational Study of Brain Tumors in
Cell Phone Users' Heads"
Exam #2 (Internet thru Fiber Optic Systems)
28 October (Live)
< 4 November (Distant Learning)
Term Paper
6 November (Live)
13 November (Distant Learning)
North American
Digital Hierarchy
 Obsolete...
...except for ‘last mile’ connectivity
 T1 byte interleaved, > T1 bit interleaved
 T1 Frame (Format for 1/8000th second)
 A 4 Wire T1 Connection:
 is
Full Duplex (1.544 Mbps in two directions)
 Carriers
often sell bandwidth in T1 & T3
chunks (& fractions thereof)
Digital Carriers
 North
American T-Carrier
DS-0
T-1
 24
phone calls
T-3
 28
64 Kbps
1.544 Mbps
44.736 Mbps
T-1
 ITU
E-1
 30
2.048 Mbps
phone calls
Switching
Crosspoint Switches
Used for Space Division Switching
Key component of CO switches
 Time Slot Interchange
Used for Time Division Switching
 CO switches perform
Space Division Switching
 Any POTS switch handling TDM lines
(such as a Tandem) performs
Time & Space Division Switching

Switching

Packet Switches
Handle Statistically Multiplexed traffic
Require Buffers
May use Crosspoints or Busses to switch
between input/output lines

Cross Connects
Under Network Control
Long Term Trunk Switching
Circuit Switching & TDM
Telephone Space Switching
Version 1.0
Human Operator
source: Salt Lake City Tribune
Telephone Space Switching
Version 2.0 Mechanical Crosspoint Switch
(a.k.a. Crossbar Switch)
source: wikipedia.com & ebay.com
Telephone Space Switching
Version 3.0
Transistorized
Crosspoint Switch
←5ESS
sources: english.turkcebilgi.com , porticus.org, &
www.mrmartinweb.com
Telephone Space Switching

V4.0 IP Routers & Gateways
IP device to IP device
→ Straight VoIP
IP device to PSTN phone
→ VoIP Provider
(Such as Skype)
→ VoIP Gateway
(Corporate owned
Interface box)
Server (IP PBX)
→ Provides PBX-like
functionality
Image source: http://t1town.com/voice-services/pbxip-pbx/
PSTN TDM
The system was designed to move voice
 But can & does haul other traffic
 Bytes organized into frames

 8,000
frames/second
 Phone call bytes occupy specified slots in
each frame
 slots

are byte sized
T-1 has 24 slots per frame
CO Connectivity
Enid
CO
CO Tulsa
TO
Stillwater
CO
Hierarchical
Direct Connect
2nd Route
CO
Minimum of two
diverse routes out
of Central Office.
2D Switching: The Animation
3
To:
Stillwater
TSI
Enid
TSI
Tulsa
3
TSI
Crosspoint
From:
Stillwater
6
Enid
Tulsa
From Stillwater (3) to Enid (17)
Watch this one
From Tulsa (3) to Stillwater (6)
From Stillwater (6) to Tulsa (3)
From Enid (17) to Stillwater (3)
2D Switching: The Animation
3
To:
Stillwater
TSI
Enid
TSI
Tulsa
3
TSI
Crosspoint
From:
Stillwater 6
Enid
Tulsa
From Stillwater (3) to Enid (17)
From Tulsa (3) to Stillwater (6)
From Stillwater (6) to Tulsa (3)
From Enid (17) to Stillwater (3)
2D Switching: The Animation
6
3
TSI
Enid
TSI
Tulsa
3
TSI
To:
Stillwater
3
3
Crosspoint
From:
Stillwater
Enid
Tulsa
From Stillwater (3) to Enid (17)
From Tulsa (3) to Stillwater (6)
From Stillwater (6) to Tulsa (3)
From Enid (17) to Stillwater (3)
2D Switching: The Animation
6
TSI
Enid
TSI
Tulsa
TSI
To:
Stillwater
3
3
Crosspoint
From:
Stillwater
Enid
Tulsa
From Stillwater (3) to Enid (17)
From Tulsa (3) to Stillwater (6)
From Stillwater (6) to Tulsa (3)
From Enid (17) to Stillwater (3)
2D Switching: The Animation
6
To:
Stillwater
TSI
Enid
TSI
Tulsa
TSI
Crosspoint
From:
Stillwater
Enid
Tulsa
From Stillwater (3) to Enid (17)
From Tulsa (3) to Stillwater (6)
From Stillwater (6) to Tulsa (3)
From Enid (17) to Stillwater (3)
2D Switching: The Animation
6
3
TSI
Enid
TSI
Tulsa
TSI
6
Crosspoint
From:
Stillwater
To:
Stillwater
Enid
3
Tulsa
From Stillwater (3) to Enid (17)
From Tulsa (3) to Stillwater (6)
From Stillwater (6) to Tulsa (3)
From Enid (17) to Stillwater (3)
From:
Stillwater
TSI
Enid
TSI
Tulsa
TSI
6
Crosspoint
2D Switching: The Animation
3
To:
Stillwater
3
Enid
Tulsa
From Stillwater (3) to Enid (17)
From Tulsa (3) to Stillwater (6)
From Stillwater (6) to Tulsa (3)
From Enid (17) to Stillwater (3)
2D Switching: The Animation
TSI
Enid
TSI
Tulsa
TSI
To:
3Stillwater
Crosspoint
From:
Stillwater
3Enid
Tulsa
From Stillwater (3) to Enid (17)
From Tulsa (3) to Stillwater (6)
From Stillwater (6) to Tulsa (3)
From Enid (17) to Stillwater (3)
Crosspoint Switch: Time Slot 6
From:
Stillwater
Crosspoint
Closed (On)
Enid
Crosspoint
Open (Off)
Tulsa
Byte
To:
Stillwater
To:
Tulsa
Enid
2D Switching: The Animation
TSI
Enid
TSI
Tulsa
TSI
6
Crosspoint
From:
Stillwater
To:
Stillwater
Enid
Tulsa
From Stillwater (3) to Enid (17)
From Tulsa (3) to Stillwater (6)
From Stillwater (6) to Tulsa (3)
From Enid (17) to Stillwater (3)
Local Loops
Simplified Central Office Switch
Space
Switch
Hybrid
TDM
deMux
A/D
TDM
Mux
Echo
Canceler
+
Local Loops
D/A
POTS Time & Space Switching
Space
Switch
Hybrid
D/A
TDM
deMux
A/D
TDM
Mux
Echo
Canceler
+
Carrier Leased Line Network
Cross-Connect
Carrier reserves BW from pool for our use.
Cross-Connects assign N byte sized time slots
8,000 times/second = N*8*8000 bps.
Cross Connect: Same Innards
TSI
Enid
TSI
Tulsa
TSI
6
Crosspoint
From:
Stillwater
To:
Stillwater
Enid
Tulsa
From Stillwater (3) to Enid (17)
From Tulsa (3) to Stillwater (6)
From Stillwater (6) to Tulsa (3)
From Enid (17) to Stillwater (3)
Packet Switch using Crosspoint Switching
Input:
Line 1
Line 2
Crosspoint
Closed (On)
Line 3
Crosspoint
Open (Off)
Packet
Output:
Line 1
Line 3
Line 2
POP's...



Customers can tie into Carrier's Network Here
Mix all sorts of traffic onto the fiber
Use either
 Cross Connects to allocate trunk bandwidth via
Circuit Switching & Time Division Multiplexing
 Routers & Switches to allocate trunk bandwidth via
Packet Switching and StatMux
 Lambda Switches to allocate entire light waves via
Circuit Switching
 Or a mixture of these
Hybrid TDM Trunking
(Potentially most efficient network)
Fixed Rate
Bursty Data
Packet
Switch
TDM
Switch
SONET
OTN
Fixed Rate traffic assigned sufficient bytes every 1/8000th
second.
Bursty Data Traffic is aggregated and StatMuxed onto a
common fabric (such as Internet routers).
Aggregate streams are TDM cross connected onto fiber.
Hybrid POP offers best potential
Carrying Capacity...
Hybrid
Carrying
Capacity
Cell Switch
StatMux
Packet Switch
StatMux
Circuit Switch
TDM
0% Data
100% TST
Offered Mix
100% Data
0% TST
Hybrid Network
Byte
Aware
Cross-Connect
Fixed Rate Traffic: CSTDM bandwidth based on Peak Rates
Bursty Traffic: Access lines aggregated onto higher load trunk.
Packet Switch StatMux Trunks are CSTDM.
A Typical Hybrid POP
Mixes all sorts of traffic onto the fiber...
 ...using Cross Connects & multiplexers
Circuit Switching
Time Division Multiplexing
 Fiber BW is dedicated to each service
 May have other switches
(Voice, Ethernet, Routers, SONET, OTN)
 POP doesn’t have switch needed?
Traffic is back-hauled to nearest switch.
Trade-off: Fiber Bandwidth vs.
Cost of more Switches

Backhauling...
Tulsa POP
OKC
POP
If a OKC Customer wants an Ethernet
connection & the nearest switch is in Tulsa,
the carrier will cross connect the leased line
to the Tulsa switch.
Ethernet Switch
Customer Switch
Ethernet Trunk
Backhauled Line
Dallas POP
Fiber in the ground
Leased Line
Backhauling...
Tulsa POP
OKC
POP
If a OKC Customer wants an Ethernet
connection & the nearest switch is in Tulsa,
the carrier will cross connect the leased line
to the Tulsa switch.
Ethernet Switch
Dallas POP
Customer Switch
Ethernet Trunk
Backhauled Line
Fiber in the ground
Leased Line
Hypothetical Hybrid POP
Fiber
2.5, 10, 40
or 100 Gbps
Optical Switch
Fiber
Cross
Connects
Leased Lines
CO Trunks
Best Potential
Carrying Capacity
of any switched
network.
Internet
Router
POTS
TimeSpace
Switch
Hypothetical Hybrid POP
Fiber
Fiber
Cross
Connects
Leased Lines
CO Trunks
Will likely see...
Through Traffic
Internet
Router
POTS
TimeSpace
Switch
Hypothetical Hybrid POP
Fiber
Fiber
Cross
Connects
Leased Lines
CO Trunks
May see...
Digitized TV
Internet
Router
POTS
TimeSpace
Switch
Hypothetical Hybrid POP
Fiber
Fiber
Cross
Connects
Leased Lines
CO Trunks
May see...
ISP Trunks
Internet
Router
POTS
TimeSpace
Switch
Hypothetical Hybrid POP
Fiber
Fiber
Cross
Connects
Leased Lines
CO Trunks
Will likely see...
ISP
Local Connections
Internet
Router
POTS
TimeSpace
Switch
Hypothetical Hybrid POP
Fiber
Fiber
Cross
Connects
Leased Lines
CO Trunks
Will likely see...
Leased Lines
Internet
Router
POTS
TimeSpace
Switch
CO Connectivity
CO
TO
CO
TO
CO
Hierarchical
Direct Connect
2nd Route
CO
Minimum of two
diverse routes out
of Central Office.
Hypothetical Hybrid POP
Fiber
Fiber
Cross
Connects
Leased Lines
CO Trunks
May see...
CO Direct
Connections
Internet
Router
POTS
TimeSpace
Switch
Hypothetical Hybrid POP
Fiber
Fiber
Cross
Connects
Leased Lines
CO Trunks
Will likely see...
Tandem POTS
Switch Traffic
Internet
Router
POTS
TimeSpace
Switch
Circuit Switch TDM Trunking
(Eighties ‘Private Line’ Network Model
Evolved into Hybrid Network)
Fixed Rate Traffic
Bursty Data Traffic
TDM
Switch
Trunk
Fixed Rate traffic assigned sufficient bytes every 1/8000th
second.
Bursty Data Traffic receives dedicated trunk BW based
on peak input (line) rates.
Circuit Switched TDM
Network POP
Copper, RF,
Fiber
Copper, RF,
Fiber
Cross
Connects
Leased Lines
CO Trunks
‘80’s Network Model.
Evolved to Hybrid.
POTS
TimeSpace
Switch
No effort is made to
aggregate bursty data
leased line traffic onto
fewer high speed packet
switched StatMuxed
trunks...
Hybrid POP
Fiber
Fiber
Cross
Connects
Leased Lines
CO Trunks
Best Potential
Carrying Capacity
of any switched
network.
Internet
Router
POTS
TimeSpace
Switch
... which is done in a
Hybrid network.
ATM StatMux Trunking
(Tomorrow's Network Model? Nope.)
Fixed Rate Traffic
Bursty Data Traffic
ATM
Switch
SONET OC-N
Assumptions:
Fixed Rate Traffic assigned to CBR VC's.
CBR traffic gets near-TDM like service.
Data Traffic is StatMuxed onto the remaining trunk BW.
Cell Switched StatMux
Network POP
SONET
Fiber
SONET
Fiber
ATM
Switch
Leased Lines
CO Trunks
ATM Model
Internet
Router
POTS
TimeSpace
Switch
Packet Switch StatMux Trunking
(Pure Internet Model)
Fixed Rate Traffic
Bursty Data Traffic
Router
SONET or OTN
Assumptions:
All Fixed Rate Traffic is packetized.
All traffic is Statistically Multiplexed onto the trunk BW.
Packet Switched StatMux
Network POP
Fiber
Fiber
Routers
Leased Lines &
Local Connections
100% Internet Model
Voice
Switch
Local Loops
Fiber Optic Cable
1 1/4 inch
SC
100 m Fiber Cable




Suppose need to move 2.5 Gbps binary bit stream
 Would use light pulses (very hi freq EM waves)
 Energy centered up around 200,000 GHz
 90% of power is within + 2.5 GHz of center freq
 99% of power is within + 25 GHz of center freq
Fiber has Wide Bandwidth → Loss same at all freqs
0.2 dB/Km loss → 0.02 dB loss over 100 m
 Power out = Power in * 0.9954
To get 1 mwatt out need 1.005 mwatt input
100 m RG-58 Coax Cable




Suppose need to move 2.5 Gbps binary bit stream
 Would use square electrical pulses (lower freq EM waves)
 90% of power is < 2.5 GHz
 99% of power is < 25 GHz
Coax has Narrow Bandwidth → Loss not same at all freqs
At 0 Hz, suppose 0 dB loss over 100 m
 Power out = Power in * 1
At 2.4 GHz, loss = 38.9 dB/100 feet
(38.9 db/100 ft)(328.1 ft/100m) = 127.6 dB
 Power out = Power in * 173.7(10-15)

To get 1 mwatt out at 2.4 GHz, need to inject 5.8 Gwatts
 High
Frequency energy gets severely attenuated
 Can't move a 2.5 Gbps bit stream 100m over RG-58 coax
Mechanical Fiber Splice

Corning CamSplice
 Strip
& Cleave Fibers
 Insert until they touch
 Twist cams until secure
Claims 3% - 7% Signal Loss
 Short Haul splicing

source: www.corningcablesystems.com
Fusion Fiber Splice
Automatically
Aligns fibers
 Electrically fuses
 Claims < 1% Signal
Loss
 Long Haul splicing

source: www.corningcablesystems.com
Elements of Optical Networks
 Fiber
 Ultra-pure
Glass
Typical Window absorbs ≈ 10% of light
2 Km of typical fiber absorbs ≈ 10% of light
 Core/Cladding Boundary will totally reflect
light from Core hitting at shallow angles
 Bending
limitations for fiber cables
 Multi-Mode
Fiber used on short hauls
(LAN’s)
 Single-Mode Fiber used on long hauls
(WAN’s)
Elements of Optical Networks

Erbium Doped Fiber Amplifier (EDFA)
 All
optical amplifiers. Boost signal power.
 Add some noise to the signal in the process

Regenerative Repeaters (Regens)
 Cleans
up optical signal and restores timing
at the cost of occasional bit errors
 Requires Optical-Electronic-Optical (OEO)
conversion
 Basically a Fiber Optic Receiver (photo & bit
detector) and Laser Transmitter stuck backto-back
Fiber Span Example
Assumptions:
1 mw in
0.2 db/Km
2.5 Gbps
RCVR Single Sample Bit Detector
 200 km → P(Bit Error) ≈ 50(10-9)
 EDFA midway between XMTR & RCVR
→ 300 km has about same P(BE)
→ 200 km has P(BE) ≈ 0.0

Fiber Optic Transmission Systems

Short Haul
 FOTS
Transmitter...
 ...connected to fiber...
 ...connected to a FOTS Receiver.

Medium Haul
 FOTS
Transmitter connected to a fiber...
 ....connected to an EDFA followed by fiber...
(1 or more times)
 ...connected to a FOTS Receiver
Fiber Optic Transmission Systems

Long Haul
 FOTS
Transmitter connected to a fiber...
 ....connected to an EDFA followed by fiber...
(1 or more times)
 ...connected to a Regen followed by fiber...
 (EDFA & Regen combo repeated 1 or more times)
 ....connected to an EDFA followed by fiber...
(1 or more times)
 ...connected to a FOTS Receiver
SONET

Optical Signal Standard (OSI Level 1)
 Optical

Carrier - N (OC-N). Used on Fiber.
Electrical Standard (OSI Level 1 & 2)
 Synchronous
Transport Signal - N (STS-N)
 Used internally in SONET hardware
 STS-N signal is converted to OC-N signal at
transmitter laser

Current technology requires optical-toelectrical (O-E-O) conversions at switches,
hence STS protocol.
SONET Hierarchy

Basic Building Block:
 51.84
Mbps STS-1
 8,000 frames/second
 810 bytes/frame, 36 bytes for OA&M

STS-N?
N

byte interleaved STS-1 signals (TDM)
OC-1
51.84 Mbps
OC-3
155.52 Mbps
OC-12 622.08 Mbps
OC-48 2.48832 Gbps
OC-192 9.95328 Gbps
OC-768 39.81312 Gbps
Leased Line Sizes










Fractional T1 (DS0 increments)
T1 1.5 Mbps
Fractional T3 (T1 increments)
T3 45 Mbps
OC-1
51.84 Mbps
OC-3
155.52 Mbps
OC-12 622.08 Mbps
At these speeds,
OC-48 2.48832 Gbps
customer might
just lease a dark
OC-192 9.95328 Gbps
fiber strand, or
OC-768 39.81312 Gbps
wavelength.
SONET
Allows rapid fault recovery
 Designed back in days when voice dominated.

Voice traffic tends to be geographically localized.
 Web traffic geographically dispersed.
 SONET Ring Architectures (50 msec recovery) have
limited circumferences. Not so hot for web traffic.

SDH
Synchronous Digital Hierarchy
ITU version of SONET
Basic building block is 155.52 Mbps
 OTN ≈ SONET V2.0

Designed for today where bursty traffic dominates
 Uses packet switching

Ethernet Fiber Standards suitable for MAN
source: "Evolution of Ethernet Standards in the IEEE 802.3 Working Group", IEEE Communications Magazine, August 2013
Traffic Growth

It’s becoming expensive to continually increase
fiber line speeds
OC-768 (40 Gbps) fastest SONET currently available
 OTU4 (111.8 Gbps) fastest OTN currently available



104.8 Gbps usable
Cheaper to multiplex slower speed TDM signals
onto the fiber
Take SONET OC-48’s, 192’s, or 768's...
 ...driving lasers tuned to different frequencies...
 ...shoot everything down one fiber.
Result = WDM (OSI Layer 1)
 As of 2014, gear is available to WDM up to ≈ 10 Tbps
on a single strand

OTN

OTU1 2.66 Gbps
 Can

OTU2 10.70 Gbps
 Can

carry an OC-192, 10 Gbps Ethernet
OTU3 43.01 Gbps
 Can

carry an OC-48
carry an OC-768, 40 Gbps Ethernet
OTU4 112 Gbps
 Can
carry 100 Gbps Ethernet
f1
f2
f3
f4
OC-192
OC-192
OC-192
OC-192
FDM
Different channels use some of
the frequency all of the time.
frequency
f1
f2
f3
f4
OC-192
OC-192
OC-192
OC-192
WDM
FDM over fiber is called
Wavelength Division Multiplexing.
frequency
One λ
Zoom in on one laser frequency band,
and you’ll either see TDM or Statmux.
frequency band f1
1
2
3
4
Early 90's…
STS-12
Laser
@ f1
OC-12
Fiber in the
ground
Detector
STS-12
WDM: 32 OC-768’s (1.274 Tbps)
#1 STS-768 Laser
Detector #1 STS-768
#1
@ f1
#2 STS-768 Laser
Detector #2 STS-768
#2
@ f2
Fiber in the
ground
#32 STS-768 Laser
@ f32
Optical
Combiner
Optical
Splitter
Detector #32 STS-768
#32
Systems are also available that can map an arbitrary input
(doesn’t have to be SONET or OTN based) onto an optical wave.