Public Network Principles

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Transcript Public Network Principles

3. Evolution of network technologies
3.1. Evolution of transport technologies
(backbone transport - switching/routing and transmission
systems)
3.2. Evolution of access networks’ technologies to
broadband (xDSL, CATV, Broadband Wireless Access)
3.3. Evolution of mobile networks (to 3G and beyond)
3.1. Evolution of transport technologies
A. Public Network Principles
Wireless
Technologies
Optical Fiber
Twisted Pair
Transport (Core/
Backbone) Network
Cable/Coax
Powerline
Access Gateway
Switching/
Routing
Transmission
Network
Terminations
Access Network
These 3 techniques will be discussed next
B. Evolution of switching technologies
DE-NG (IP)
MPLS
G-MPLS
ISDN
Hand
Self-dial
1935
telegraph
Cr-B
QE
55
70
DE-2
FR
IP/X25/SMDS
Cellular
radio
NMT
UMTS/IMT-2000
Public
DE-1
1884
Operator
GSM
Ethernet
PABX-1
PABX-2
Telegraph
1840
Manual
switching
1900
Electromechanics
1950
Analog
1975
1980
PABX-NG (IP)
Private
Gbit Ethernet 10 Gbit Ethernet
Digital
1990
2000
Years
Switching technologies (Cntd)
АТМ
(CS, 80-s,
B-ISDN)
CS
(PSTN)
FR
(FS, 70-s,
DN)
Х.25
(PS-VC, 60-s,
DN)
Connection-oriented
technologies
IP
(PS-DG,
60-s, Internet)
Connectionless-oriented
technologies
MS
(Tlg)
Transport technologies in
network backbones
BACKBONE OPTIONS
ATM
IP
MPLS
OB
C. Transport technologies in
network backbones - ATM
BACKBONE OPTIONS
ATM
IP
MPLS
OB
ATM and the IETF model
• Layer
Application
Transport
Network
Data Link
Physical
1/2
• Quality of Service (QoS)
• Multimedia Transport
Constant Bit Rate (CBR) - Voice
Variable Bit Rate (VBR) - WWW
Available Bit Rate (ABR) – E-mail
Unspecified Bit Rate (UBR)
ATM
Putting ATM to work
1
Voice
• Delay
• Delay Variation
• Loss
Data
• Delay
• Delay Variation
• Loss
Video
• Delay
• Delay Variation
• Loss
Multimedia
• Delay
• Delay Variation
• Loss
2
3
4
5
• Constant Bit Rate for switched TDM traffic
(AAL1):
ATM QoS
– Access Aggregation (TDM for GSM/GPRS, ATM
for UMTS)
– Digital Cross-Connect
– Backbone Voice Transport - Basic
• Real-time Variable Bit Rate for bursty,
CBR
rt-VBR
LINE
RATE
(LR)
nrt-VBR
ABR
UBR
UBR+
jitter-sensitive traffic:
– Backbone Voice Transport – Advanced (AAL2)
– Optional for Packetized Access Transport &
Aggregation (3G UTRAN, 2G CDMA)
• Non real-time Variable Bit Rate for
bursty high priority data traffic:
– 2.5G data services
• Unspecified Bit Rate+ with Minimum
B/W Guarantee for internal data:
– Operations, Admin & Maintenance (element
management, stats collection, network
surveillance, …)
– Billing data
– Internal LAN traffic (email, web, file sharing, …)
between operator’s business offices
ATM’s role in the network’s segments
Premise
• LAN/Desktop
• Campus Backbone
Access
• Low Speed (56/64)
• Medium Speed (E1)
• High Speed (>E1 to SDH)
• Integrated Access
Backbone
• Voice
• Data
• Video
• Multimedia
1
2
3
4
5
ATM and the “Competition”
Premise
• LAN/Desktop - Ethernet, HS Ethernet, Gigabit Ethernet
• Campus Backbone - HS Ethernet, Gigabit Ethernet
Access
• Low Speed (56/64) - ISDN, ADSL
• Medium Speed (E1) – xDSL, E1
• High Speed (>E1 to SDH) - SDH
• Integrated Access - E1, xDSL, SDH
Backbone
• Voice
• Data
• Video
• Multimedia
Traditional Telephony, IP Backbones
Optical Backbones, IP Backbones
Optical Backbones, IP Backbones
Optical Backbones, IP Backbones
ATM Summary
Multimedia
Not used much on Premise
Present use in Backbone
Predictable Performance/Guaranteed QoS
D. Transport technologies in
network backbones - IP
BACKBONE OPTIONS
ATM
IP
MPLS
OB
IP and the IETF Model
Application
• Network Layer (Layer 3)
Transport
IP
Network
•
Data Link
•End-to-End Addressing/Delivery
•“Best Effort” Service
Physical
Putting IP to work
1
Voice
• Delay
• Delay Variation
• Loss
Data
• Delay
• Delay Variation
• Loss
Video
• Delay
• Delay Variation
• Loss
Multimedia
• Delay
• Delay Variation
• Loss
2
3
4
5
IP’s Role in the network’s segment
Premise
• LAN/Desktop
• Campus Backbone
Access
• Low Speed (56/64)
• Medium Speed (E1)
• High Speed (>E1 to SDH)
• Integrated Access
Backbone
• Voice
• Data
• Video
• Multimedia
1
2
3
4
5
IP and the “Competition”
Premise
•LAN/Desktop
•Campus Backbone
No Real Competition
No Real Competition
Access
•Low Speed (56/64)
•Medium Speed (E1)
•Integrated Access
ISDN
xDSL, non-channelized E1
E1, multiple E1, Frame Relay, SDH
Backbone
• Voice
• Data
• Video
• Multimedia
Traditional Telephony
Optical Backbones
Optical Backbones
Optical Backbones, ATM Backbones
Why use IP?
-Wide acceptance
Internet popularity
Global reach
- IP Standards
Mature standards
Interoperability
IP Protocol characteristics
Simple protocol
Good general purpose protocol
“Best Effort” Protocol
IP summary
Globally popular
Originally developed for data
Mature standards
Interoperability
“Best Effort” Protocol
Voice over IP gaining popularity
We need a better Internet
Reliable as the phone
Working right away as a TV set
Mobile as a cell phone and
Powerful as a computer
Next Generation
Networks
Main directions of
improvement
1. Scalability
2. Security
3. Quality of service
4. Mobility
IPv6
E. Transport technologies in
network backbones - MPLS
BACKBONE OPTIONS
ATM
IP
MPLS
OB
MPLS Model
LER
A
LER
B
LSR
LSR
FEC
LSP
• Routers that handle MPLS and IP are called Label Switch Routers (LSRs)
• LSRs at the edge of MPLS networks are called Label Edge Routers (LERs)
• Ingress LERs classify unlabelled IP packets and appends the appropriate
label.
• Egress LERs remove the label and forwarding the unlabelled IP packet
towards its destination.
• All packets that follow the same path (LSP- Label Switched Part) through the
MPLS network and receive the same treatment at each node are known as a
Forwarding Equivalence Class (FEC).
MPLS adds a connection-oriented paradigm into IP networks
E. Switching Technologies - Summary
• Driving forces (mid of 80th) - Common platform
for different types of traffic
• ISDN is not suitable (N-ISDN - low bit rates,
circuit switching)
• ATM will not become as the most important
switching technology since 2000s
• Main competitors (Performance/Price)
# Ethernet (LANs)
# xDSL (Access)
# IP/MPLS (Backbones)
F. Transmission technologies in
network backbones - OB
BACKBONE OPTIONS
ATM
IP
OB
MPLS
Stated data rates for the most important end-user
and backbone transmission technologies -1
Technology
Speed
GSM mobile telephone
9.6 to 14.4 kbps
service
High-Speed CircuitSwitched Data service Up to 56 kbps
(HSCSD)
Plain Old Telephone
Up to 56 kbps
System (POTS)
Dedicated 56Kbps on
56 kbps
frame relay
DS0
64 kbps
General Packet Radio
56 to 114 kbps
System (GPRS)
BRI: 64 kbps to 128 kbps
PRI: 23 (T-1) or 30 (E1)
assignable 64 kbps channels
ISDN
plus control channel; up to
1.544 Mbps (T-1) or 2.048
(E1)
Physical Medium Application
Wireless
Mobile telephone for business and
personal use
Wireless
Mobile telephone for business and
personal use
Twisted pair
Home and small business access
Various
All
Wireless
BRI: Faster home and small
BRI: Twisted pair PRI: business access
T-1 or E1 line
PRI: Medium and large enterprise
access
IDSL
128 kbps
Twisted pair
AppleTalk
230.4 kbps
Twisted pair
Enhanced Data GSM
384 kbps
Environment (EDGE)
Business e-mail with fairly large
file attachments
The base signal on a channel in the
set of Digital Signal levels
Mobile telephone for business and
personal use
Wireless
Faster home and small business
access
Local area network for Apple
devices; several networks can be
bridged; non-Apple devices can
also be connected
Mobile telephone for business and
personal use
Stated data rates for the most important end-user
and backbone transmission technologies -2
Technology
Satellite
Speed
Physical Medium
400 kbps
(DirectPC and Wireless
others)
Application
Faster home and small
enterprise access
Frame relay
56 kbps to
1.544 Mbps
Twisted pair or
coaxial cable
Large company backbone
for LANs to ISP
ISP to Internet infrastructure
DS1/T-1
1.544 Mbps
Twisted pair,
coaxial cable, or
optical fiber
Large company to ISP
ISP to Internet infrastructure
Wireless
Mobile telephone for
business and personal use
(available in 2002 or later)
Universal Mobile
Telecommunications Service Up to 2 Mbps
(UMTS)
E-carrier (E-1)
T-1C (DS1C)
IBM Token Ring/802.5
DS2/T-2
Digital Subscriber Line
(DSL)
Twisted pair,
coaxial cable, or
optical fiber
Twisted pair,
3.152 Mbps
coaxial cable, or
optical fiber
Twisted pair,
4 Mbps (also
coaxial cable, or
16 Mbps)
optical fiber
Twisted pair,
coaxial cable, or
6.312 Mbps
optical fiber
Twisted pair (used
512 Kbps to 8
as a digital,
Mbps
broadband medium)
2.048 Mbps
32-channel European
equivalent of T-1
Large company to ISP
ISP to Internet infrastructure
Second most commonlyused local area network
after Ethernet
Large company to ISP
ISP to Internet infrastructure
Home, small business, and
enterprise access using
existing copper lines
Stated data rates for the most important end-user
and backbone transmission technologies -3
Technology
E-2
Cable modem
Ethernet
IBM Token
Ring/802.5
E-3
Speed
Physical Medium
Twisted pair, coaxial cable, or optical
8.448 Mbps
fiber
512 kbps to Coaxial cable (usually uses Ethernet);
52 Mbps
in some systems, telephone used for
upstream requests
10BASE-T (twisted pair); 10BASE-2
10 Mbps
or -5 (coaxial cable); 10BASE-F
(optical fiber)
16 Mbps
Twisted pair, coaxial cable, or optical
(also 4
fiber
Mbps)
34.368
Twisted pair or optical fiber
Mbps
Application
Carries four multiplexed E-1 signals
Home, business, school access
Most popular business local area network
(LAN)
Second most commonly-used local area
network after Ethernet
Carries 16 E-l signals
ISP to Internet infrastructure
Coaxial cable
Smaller links within Internet
DS3/T-3
infrastructure
ISP to Internet infrastructure
51.84 Mbps Optical fiber
Smaller links within Internet
OC-1
infrastructure
Between router hardware and WAN lines
Short-range (50 feet) interconnection
High-Speed Serial Up to 53
HSSI cable
Mbps
between slower LAN devices and faster
Interface (HSSI)
WAN lines
100BASE-T (twisted pair); 100BASE- Workstations with 10 Mbps Ethernet
100 Mbps
Fast Ethernet
F (optical fiber)
cards can plug into a Fast Ethernet LAN
44.736
Mbps
Stated data rates for the most important end-user
and backbone transmission technologies -4
Technology
Speed
Fiber Distributed-Data
Interface (FDDI)
100 Mbps Optical fiber
T-3D (DS3D)
135 Mbps Optical fiber
E-4
OC-3/SDH
E-5
OC-12/STM-4
Gigabit Ethernet
OC-24
OC-48/STM-16
OC-192/STM-64
OC-256
139.264
Mbps
155.52
Mbps
565.148
Mbps
622.08
Mbps
1 Gbps
1.244
Gbps
2.488
Gbps
10 Gbps
13.271
Gbps
Physical Medium
Optical fiber
Optical fiber
Optical fiber
Application
Large, wide-range LAN usually in a large
company or a larger ISP
ISP to Internet infrastructure
Smaller links within Internet infrastructure
Carries 4 E3 channels
Up to 1,920 simultaneous voice conversations
Large company backbone
Internet backbone
Carries 4 E4 channels
Up to 7,680 simultaneous voice conversations
Optical fiber
Internet backbone
Optical fiber (and
"copper" up to 100
meters)
Workstations/networks with 10/100 Mbps Ethernet
plug into Gigabit Ethernet switches
Optical fiber
Internet backbone
Optical fiber
Internet backbone
Optical fiber
Backbone
Optical fiber
Backbone
Copper
cable
1935
Modulation methods
Transmission media
Evolution of transmission technologies
SDH
PDH
WDM
all
optical
Wavelength multiplexing
Time multiplexing, TDM
Frequency modulation, FDM
1900
1970
1980
1990
2000
Years
Technological limitations of different
transmission media
Limits of Transmission Media
Mbit/s
Transmission Capacity [Mbit/s]
10000
1000
Fiber
250
100
Cellular
Wireless*
Coax
10
1
Copper Twisted Pair
0,1
0,1
1
10
100
Distance [km ]
*Capacity in Mbit/s/sq_km, Bandwidth 500 MHz
Optical fibers are the only alternative at high bandwidth and distances
Optical systems move
from backbone to access
Access
Metro
Backbone
Optical
Copper
yesterday
Fiber optics
and laser
ISDN POTS
5 Years
today
Optical
Copper
ADSL
additional: color filter and
optical amplifier
10-15 Years
tomorrow
Optical
additional: optical switch, color
converter
Entry process of optical systems into access occurs very slowly
... Prognosis 10-15 years, reason: exchange of copper cables and maturity of technologies
Today optical transmission system consists
mainly of electronics and passive optical
components
Signal
Multiplexer
SDH networks:
Electrical
signal
Amplifier
Cross connector
TDM
MUX,
Crossconnect,
control
Optical fiber
TDM
MUX
Passive
optics
Optoelectronics
Active
optics
Electronics
WDM networks:
TDM
MUX
Electrical
signal
Optical
signal
Electronics
Control
WDM
MUX
Optical fiber
Passive
optics:
- lenses
- prisms
- grating
Passive
optics
Active
optics
Passive
optics:
- lenses
- grating
- mirrors
• SDH and WDM process signals most of the time only
electronically
• Amplifiers are the only active optical elements in the network
WDM
MUX,
Crossconnect
Day after tomorrow:
All-optical switching and multiplexing
Signal Multiplexer
Amplifier
Switch
Optical
signal
Control
WDM
MUX
Optical fiber
Passive
optics:
- lenses
- prisms
- grating
Switch
Matrix
Passive
optics
Aktive
Optik
Active
optics:
- Switch
- color converter
- amplifier
• All-optical systems process signals only optically
• Electronics disappear
• Nortel (03/2002): large scale stand-alone optical switches
are likely for longer term market requirements
Future photonic switches
• Optics are good for transport
• Electronics are good for switching
• Electronics as far as possible
Evolution instead of Revolution  at least, 5
years for first all-optical systems in backbone
and metro area
G. Concluding remarks - growth of network
capacity and “Death of distance” phenomenon
• Growth of network capacity
reduction of information
transmission costs
• New generation of transmission systems –
new ratio Cost of transmission/Bandwidth
• PCM
SDH/SONET
DWDM
• Bandwidth becoming a less dominating factor in cost of connection
• Cost of one-bit-transmission has an obvious tendency to become very
close to zero in long distance communications systems
• “Flattened” networks
• “Death of distance” phenomenon (F. Cairncross, 1997)
• Challenges for operators
Bandwidth using
• 32 terrestrial carriers connecting to the New York
metropolitan area have a combined potential capacity of
818.2 Terabits per second. Of that, only 22.6 Terabits per
second -- 2.8 percent -- of network bandwidth is actually
in use
•
City
Int'l IP
Bandwidth,
Gbit/s
London
550.3
Paris
399.4
Frankfurt
320.2
Amsterdam 267.1
Using
Bandwidth,
Gbit/s
9,5
9,3
10,3
8,2
Development of costs for IC sector
Cost of information processing $ per instruction per second
Cost of a three-minute telephone call from New York
to London, $
IBM Mainframe
100
350
300
Cray I
10
250
Sun Microsystems 2
IBM PC
1
US$
$ per instruction per second
Digital VAX
200
150
100
0,1
50
Pentium-chip PC
0,01
1974
1979
1975
1985
years
1982
1994
to be
continued
0
1930
1940
1950
1960
1970
1980
years
Source: Economist
1990
to be
continued
1996