Transcript computer networking

COMPUTER NETWORKING
Trends
Dr. Arjan Durresi
Department of Computer and Information Science
Indiana University Purdue University
Indianapolis, USA
www.cs.iupui.edu/~durresi, [email protected]
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Overview
Networking – tools to improve communications
 Network Architecture
 Evolution of Networking
 Trends in Networking
 Why we need a “new” Internet?
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Communication
Exchange of Information (Communication),
makes possible the Human society and the
civilization
 Improvements in communication - milestones
in the history of civilization
 Language
 Writing
 Books
 Electronic communication, Internet
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Communication with computers
Tools created to increase and enhance our
capabilities:
 Cars, Airplanes, Microscopes, Telescopes
 Telegraph , Telephone to communicate
 Computers born to store and process
information
 Computers to communicate; Network - more
than two computers
Each epoch in human history is dominated by
one tool:
 Industrial Revolution: Steam engine
 Information Age: Computers and networks
 The Internet is the universal medium of
communication
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The Value of Networks
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Metcalfe's law
 The value of a network is
proportional to the square of
its nodes
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Spectacular Progress
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IT & Telecom Evolution
Wireless Sensor Nets
Telecom
Internet + Telecom
Cell Phones
Everywhere
(~2000)
The Virtual World
Global
Internet
(~2000)
virtualized via sensors & actuators
The Physical World
Information Tech
control
data
Global Internet for
data & telecom
Digital
Media
Convergence
(2000-2010)
Pervasive
Computing
(2015-)
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The New Economy
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Fundamental transformation in economy as businesses
and individuals capitalize on new technologies, new
opportunities, and national investments in computing,
information, and communication technologies
New telecommunication technologies have contributed
significantly to the New Economy
 New product capabilities for businesses and
consumers
 More efficient forms of industrial organization
made possible by cheaper and more efficient
communications
While telecom sector accounts for about one percent
of US economy, it is responsible for generating about
ten percent of the nation’s economic growth
 How to sustain or improve on this factor of ten?
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The New Economy
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Bureau of Labor Statistics' "Occupational
Outlook Handbook 2010-11“ about networking
area:
 2008 employment: 292,000
2018 employment: 447,800
Percentage increase: 53% – the highest
among technical carriers
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Global IP Traffic Growth Exabytes,
2011–2016
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Cisco Forecasts 56 Exabytes per
Month of IP Traffic in 2013
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Internet Video Will Generate
Three Waves of Consumer
Internet Traffic Growth
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Video
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Internet Video Already
Generates More Traffic than
the Entire U.S. Backbone in
2000
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Mobile Video
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Mobile Cloud Adoption
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Cloud Media Applications Multiply Smartphone
Traffic
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Mobility
Laptops and Mobile Broadband Handsets Drive Traffic Growth
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Mobility
Potential Growth in Data Traffic from a Single Mobile Subscriber
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Is Technology only technical stuff ?
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Technology depends on the Socio-technical System
 Social, Political, Economic, Institutional
Not simply the rational product of scientists and
engineers.
Technology makes sense when seen as part of the
society
Examples:
 Automobile engines: Internal combustion vs. steam
 Network technologies:
 OSI vs. TCP/IP vs. ATM, Ethernet vs. Token
Ring, ISDN vs. fax
 Future: Quality of Service mechanisms over the
Internet
 Future Internet
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Success Factors for New Services
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Technology not the only factor in success of a new
service
Three factors considered in new telecom services
Market
New
Service
Can there be
demand for the
service?
Technology
Can it be
implemented costeffectively?
Is the service
allowed?
Regulation
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*Market
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The network effect: usefulness of a service increases
with size of community
 Metcalfe's Law: usefulness is proportional to the
square of the number of users
 Phone, fax, email, ICQ, …
Economies of scale: per-user cost drops with
increased volume
 Cell phones, PDAs, PCs
 Efficiencies from multiplexing
S-curve: growth of new service has S-shaped curve,
challenge is to reach the critical mass
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*The S Curve
Service Penetration & Network Effect
 Telephone: T=30 years
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Automobile: T=30 years
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city-wide & inter-city links
roads
Others
 Fax
 Cellular & cordless phones
 Internet & WWW
 Napster and P2P
T
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*The S Curve
Capability
Third class of
invention
Second class of
invention
Initial class of
invention
Time
(b)
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Gartner Hype Cycle 2013
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The Bubble
Networking
Spending
Dot Coms
CLECs
Y2K
1997 1998 1999 2000 2001
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Sidgmore: Internet Traffic doubling every 40 days, 30
days, … Over-projection data networking equipment
Nearly 1/3 of all tech IPOs over the last 21 years
happened in 1999 and 2000. Source:Morgan Stanely/Chi at Opticomm
CLEC - Competitive Local Exchange Carrier
ILEC - Incumbent Local Exchange Carriers
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Regulation & Competition
Telegraph & Telephone originally monopolies
 Extremely high cost of infrastructure
 Profitable, predictable, slow to innovate
 Competition feasible with technology advances
 Long distance cost plummeted with optical
tech
 Alternative local access through cable,
wireless
 Radio spectrum: auctioned vs. unlicensed
 Basic connectivity vs. application provider
 Tussle for the revenue-generating parts
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*Standards
New technologies very costly and risky
 Standards allow players to share risk and
benefits of a new market
 Reduced cost of entry
 Interoperability and network effect
 Compete on innovation
 Completing the value chain
 Chips, systems, equipment vendors,
service providers
 Example
 802.11 wireless LAN products
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*Standards Bodies
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Internet Engineering Task Force
 Internet standards development
 Request for Comments (RFCs): www.ietf.org
International Telecommunications Union
 International telecom standards
IEEE 802 Committee
 Local area and metropolitan area network standards
Industry Organizations
 MPLS Forum, WiFi Alliance, World Wide Web
Consortium
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*Dealing with Network
Complexity
 Network complexity:
Many technologies with different features
 Not all standards are compatible, from different
organizations
 Multiple technologies to interconnect the
networks
 No single underlying theory that explains the
relationship among the parts
How to learn about the networking ?
 Focus on the concepts, go beyond the details
 When needed is easy to go from concepts to
details
 Concepts are “borrowed” among technologies.
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Cave Persons of 2050
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Success of the Internet
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*Scalability – The holy Grail
of Networking
If you can scale, everything else must be working
Mike O’Dell, Chief Technologist, UUNET
No machine has complete information about
the system state.
 Machines make decisions based only on local
information.
 Failure of one machine does not ruin the
system.
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The N 2 Problem
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For N users to be fully connected directly
Requires N(N – 1)/2 connections
Requires too much space for cables
Inefficient & costly since connections not always on
1
N = 1000
N(N – 1)/2 = 499500
2
N
4
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Computer Network Evolution
Overview
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1950s: Telegraph technology adapted to computers
1960s: Dumb terminals access shared host computer
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SABRE airline reservation system
1970s: Computers connect directly to each other
ARPANET packet switching network
 TCP/IP internet protocols
 Ethernet local area network
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1980s & 1990s: New applications and Internet growth
Commercialization of Internet
 E-mail, file transfer, web, P2P, . . .
 Internet traffic surpasses voice traffic
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Store-andforward
Packet Switching
To interconnect many computers
 Statistical multiplexing – more efficient than
time-division multiplexing
 ARPNET late 1960s
 The network is peripheral
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Local Area Networks
Emergence of LANs
 Ethernet 10Mbps, 100Mbps, 1Gbps, 10Gbps
 Ethernet everywhere: LAN and WAN
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*Internet Architecture
 Defined
by Internet Engineering Task
Force (IETF)
 Hourglass Design
FTP
HTTP
NV
TFTP
UDP
TCP
IP
NET 1
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NET 2
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NET n
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*Internet Protocol IP
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Hour-glass model:
 Glue of the Internet,
 Everything over IP, and IP over everything
 The single common language
Implemented at both hosts and routers
Accommodating heterogeneity
Minimalist approach. Best effort datagram service
One of the main reasons of the Internet’s success
TCP,UDP
IP
ATM,Ethern.
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*Elements of Computer
Network Architecture
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Congestion control inside the network
Internetworking across multiple networks using routers
Segmentation and reassembly of messages into packets
at the ingress to and egress from a network or
internetwork
End-to-end transport protocols for process-to-process
communications
Applications that build on the transfer of messages
between computers.
Intelligence is at the edge of the network.
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*Packet vs. Circuit Switching
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Architectures appear and disappear over time
 Telegraph (message switching)
 Telephone (circuit switching)
 Internet (packet switching)
Trend towards packet switching at the edge
 IP enables rapid introduction of new
applications
 New cellular voice networks packet-based
 IP supports real-time voice and telephone
network will gradually be replaced
 However, large packet flows easier to manage
by circuit-like methods
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*Network Architecture
Evolution
Telegraph Networks
 Message switching & digital transmission
 Telephone Networks
 Circuit Switching
 Analog transmission → digital transmission
 Mobile communications
 Internet
 Packet switching & computer applications
 Future Internet ?
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Internet Generations
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Internet 1.0 (1969 -1989)
 Research Project
 RFC1 – April 1969
 ARPA project started a few years earlier
 IP, TCP, UDP
 Mostly researchers
 Industry was busy with proprietary
protocols SNA, DECnet, AppleTalk, XNX
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Internet 1.0
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The pioneering research of Paul Baran in the 1960s, who
envisioned a communications network that would survive a major
enemy attacked.
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Internet 1.0
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A sketch of the packet switching network in the
United Kingdom proposed by Donald Davies, a pioneer
in networking in the 1960s.
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Internet 1.0
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A rough sketch map of the possible topology of
ARPANET by Larry Roberts. The map was drawn in the
late 1960s as part of the planning for the network
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Internet 1.0 - 2.0
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Internet Generations
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Internet 2.0 (1989 – Present) – Commerce –
New Requirements
 Security RFC1108 n 1989
 Inter-domain routing: OSPF, BGP
 IP Multicasting
 Address Shortage, IPv6
 Congestion Control, Quality of Service…
 VoIP, P2P, Skype…
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Historical Maps of Computer
Networks
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http://www.cybergeography.org/atlas/historical.html
The pioneering research of Paul Baran in the 1960s,
who envisioned a communications network that would
survive a major enemy attacked.
Donald Davies, a pioneer in networking in the 1960s
A good book Where Wizards Stay Up Late: The
Origins of the Internet, by Katie Hafner and Matthew
Lyon
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Why a new Internet?
May you live in interesting times
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The existing Internet Architecture is reaching its
limits.
New technologies, mobility, security, demand for new
services
The research community is thinking to design it from
the scratch, using what we know now.
National Science Foundation is planning a $300M+
research and infrastructure program on GENI ⇒ Most
of the networking researchers will be working on
GENI for the coming years
“Global Environment for Networking Innovations” or
GENI
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Future of the Internet
The next killer application is …
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Smartphone > PC Shipments Within 2 Years, Global –
Implies Very Rapid Evolution of Internet Access
Global Unit Shipments of Desktop PCs + Notebook PCs vs. Smartphones, 2005 – 2013E
700
2012E: Inflection Point
Smartphones > Total PCs
600
500
400
300
Annual Unit Shipments (MM)
200
100
0
2005
2006
2007
2008
2009E
2010E
2011E
Desktop PCs
Notebook PCs
Smartphones
2012E
2013E
Note: Notebook PCs include Netbooks. Source: IDC, Gartner, Morgan Stanley Research estimates.
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Global Mobile Data Growth Today is
Similar to Global Internet Growth in
the Late 1990s
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Device Diversification
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One-Quarter of Mobile Users Will
Own Two or More Mobile-Connected
Devices by 2016
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By the end of 2012, the number of mobile-connected devices
will exceed the number of people on earth, and by 2016
there will be 1.4 mobile devices per capita.
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Comparison of Global Device Unit
Growth and Global Mobile Data
Traffic Growth
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Traffic Offload from Mobile
Networks to Fixed Networks
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22 Percent of Total Mobile Data Traffic will
be Offloaded in 2016
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Machine-to-Machine Traffic to Increase
22-Fold Between 2011 and 2016
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*Trends in Network Evolution
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It’s all about services
 Building networks involves huge expenditures
 Services that generate revenues drive the network
architecture
Current trends
 Mobility
 Packet switching vs. circuit switching
 Multimedia applications
 More versatile signaling
 End of trust
 Many service providers and overlay networks
 Networking is a business
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End of Trust
Security Attacks
 Spam
 Denial of Service attacks
 Viruses
 Impersonators
 Firewalls & Filtering
 Control flow of traffic/data from Internet
 Protocols for privacy, integrity and
authentication
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Servers & Services
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Many Internet applications involve interaction
between client and server computers
 Client and servers are at the edge of the Internet
 SMTP, HTTP, DNS, …
Enhanced services in telephone network also involve
processing from servers
 Caller ID, voice mail, mobility, roaming, . . .
 These servers are inside the telephone network
 Internet-based servers at the edge can provide
same functionality
In future, multiple service providers can coexist and
serve the same customers
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The right Trade off in Networking
Need
Complexity
Cost
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User is the King => Pays the bill
What does the user really need?
Killer applications are key for the success of a
particular technology
In today’s Internet the driving need is
connectivity
 Email and web browser – killer applications,
which don’t need more QOS
Future Internet, new applications + more QOS ?
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Operations, Administration,
Maintenance, and Billing
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Communication like transportation networks
 Traffic flows need to be monitored and controlled
 Tolls have to be collected
 Roads have to be maintained
 Need to forecast traffic and plan network growth
Highly-developed in telephone network
 Entire organizations address OAM & Billing
 Becoming automated for flexibility & reduced cost
Under development for IP networks
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Transmission Technology
Relentless improvement in transmission
 High-speed transmission in copper pairs
 DSL Internet Access
 Higher call capacity in cellular networks
 Lower cost cellular phone service
 Enormous capacity and reach in optical fiber
 Plummeting cost for long distance telephone
 Faster and more information intensive
applications
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Processing Technology
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Relentless improvement in processing & storage
Moore’s Law: doubling of transistors per integrated
circuit every two years
RAM: larger tables, larger systems
Digital signal processing: transmission, multiplexing,
framing, error control, encryption
Network processors: hardware for routing, switching,
forwarding, and traffic management
Microprocessors: higher layer protocols and
applications
Higher speeds and higher throughputs in network
protocols and applications
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Software Technology
Greater functionality & more complex systems
 TCP/IP in operating systems
 Java and virtual machines
 New application software
 Middleware to connect multiple applications
 Adaptive distributed systems
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Grid Computing
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Allows users to share data, software, and computation power
over fiber optics networks
SETI (Search for Extraterrestrial Intelligence)
 About 500,000 people have downloaded the program,
generating an amount of computing power that would have
cost $100 million to purchase
“Holy Grid” – where everything is connected to everything,
running common software, able to tackle a wide range of
problems
Autonomic Computing – where integrated computer systems are
not only able to self-protecting, self-configuring, and selfhealing, but also come closer to self-managing.
Pervasive Computing – where sensors embedded in a variety of
devices and products would gather and analyze data.
 Soon trillion of sensors
With telecommunication firms becoming more dependent on
information technology, and vice versa, the two industries are
becoming more interwined.
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*Cloud Computing
Cloud Computing: Use of compute resources
that are dynamically made available based on a
request for a service provided by that cloud
 Rent recourses
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Economics of Cloud Computing
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*
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The Problem with Cloud
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*Cloud Networking
Intra Cloud Networking
 Inter Cloud Networking
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Google
Data Center
Google
Data Center
Google
Data Center
Google’s WAN
Internet
Access
ISP
Access
ISP
End User Hosts
End User Hosts
Fig. 1: Example of a private WAN for service delivery
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*Communication Network
Architecture
Network architecture: the plan that specifies
how the network is built and operated
 Architecture is driven by the network
services
 Overall communication process is complex
 Network architecture partitions overall
communication process into separate
functional areas called layers
Next we will trace evolution of three network
architectures: telegraph, telephone, and
computer networks
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Telegraphs & Long-Distance
Communications
Approaches to long-distance communications
 Courier: physical transport of the message
 Messenger pigeons, pony express, FedEx
 Telegraph: message is transmitted across a
network using signals
 Drums, beacons, mirrors, smoke, flags,
semaphores…
 Electricity, light
 Telegraph delivers message much sooner
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Optical (Visual) Telegraph
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Claude Chappe invented optical
telegraph in the 1790’s
Semaphore mimicked a person with
outstretched arms with flags in each
hand
Different angle combinations of arms
& hands generated hundreds of
possible signals
Code for enciphering messages kept
secret
Signal could propagate 800 km in 3
minutes!
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Electric Telegraph
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William Sturgeon Electro-magnet (1825)
 Electric current in a wire wrapped around a piece
of iron generates a magnetic force
Joseph Henry (1830)
 Current over 1 mile of wire to ring a bell
Samuel Morse (1835)
 Pulses of current deflect electromagnet to
generate dots & dashes
 Experimental telegraph line over 40 miles (1840)
Signal propagates at the speed of light!!!
 Approximately 2 x 108 meters/second in cable
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Electric Telegraph Networks
Electric telegraph networks exploded
 Message switching & Store-and-Forward
operation
 Key elements: Addressing, Routing,
Forwarding
 Optical telegraph networks disappeared
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Message
Message
Message
Source
Message
Switches
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Destination
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*Elements of Telegraph
Network Architecture
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Digital transmission
 Text messages converted into symbols (dots/dashes,
zeros/ones)
 Transmission system designed to convey symbols
Multiplexing
 Framing needed to recover text characters
Message Switching
 Messages contain source & destination addresses
 Store-and-Forward: Messages forwarded hop-byhop across network
 Routing according to destination address
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Bell’s Telephone
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Alexander Graham Bell (1875) working on harmonic
telegraph to multiplex telegraph signals
Discovered voice signals can be transmitted directly
 Microphone converts voice pressure variation
(sound) into analogous electrical signal
 Loudspeaker converts electrical signal back into
sound
Telephone patent granted in 1876
Bell Telephone Company founded in 1877
Signal for “ae” as in cat
Microphone
sound
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Loudspeaker
analog
electrical
signal
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sound
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Bell’s Sketch of Telephone
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Evolution of Networks
In 1890 simple telephone networks with
manually operated switches – circuit switching
 Operators replaced by mechanical switches
and 100 years later by electronic switches
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Electronic switches and exchange control
information using the common channel
signaling (CCS)
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Circuit Switching
Patchcord panel switch invented in 1877
 Operators connect users on demand
 Establish circuit to allow electrical current
to flow from inlet to outlet
 Only N connections required to central office
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1
N
N–1
3
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*Hierarchical Network Structure
Toll
CO = central office
Tandem
Tandem
CO
CO
CO
CO
CO
Telephone subscribers connected to local CO (central
office) Tandem & Toll switches connect CO’s
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Computer Connection Control
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A computer controls connection in telephone switch
Computers exchange signaling messages to:
 Coordinate set up of telephone connections
 To implement new services such as caller ID, voice mail, . . .
 To enable mobility and roaming in cellular networks
“Intelligence” inside the network
A separate signaling network is required
Computer
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Switch connects
Inlets to Outlets
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...
...
Signaling
Voice
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Elements of Telephone
Network Architecture
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IUPUI
Digital transmission & switching
 Digital voice; Time Division Multiplexing
Circuit switching
 User signals for call setup and tear-down
 Route selected during connection setup
 End-to-end connection across network
 Signaling coordinates connection setup
Hierarchical Network
 Decimal numbering system
 Hierarchical structure; simplified routing; scalability
Signaling Network
 Intelligence inside the network
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Feature
1 Energy
Efficiency
2 Mobility
Today vs. Future
Today
Always-on
Mostly
stationary
computers
3 ComputerMulti-user
Human
systems,
Relationship Machine to
machine
4 End
Single
Systems
computers
IUPUI
2- Overview - 94
Future
Green, Mostly off
Mostly mobile
objects
Multi-system user
Personal comm.
Systems
Globally distributed
systems
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Today vs. Future
Feature
5 Protocol
Symmetry
Today
Future
Communication Unequal: PDA vs.
between equals, Google, Asymmetric
Symmetric
6 Design Goal Research,
Trusted
systems
Commerce, No trust,
Map to organizational
structure
7 Ownership
Hierarchy of
ownerships,
administrations,
communities
IUPUI
No concept of
ownership
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Today vs. Future
8
Feature
Sharing
9
Today
Sharing,
Interference,
QoS Issues
Packets
Switching
units
10 Applications Email and
Web
IUPUI
2- Overview - 96
Future
Sharing and Isolation,
Critical
Infrastructures
Packets, Circuits,
Wavelengths, …
Information retrieval,
Distributed
Computing and
Storage, Data
diffusion
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Security Mechanisms
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IUPUI
Not a single silver bullet
Develop multiple layers of defense
Employ as many layers of defense as needed – risk,
resource profiles
Castle, moat, drawbridge, mountain-top lookout,
perimeter wall, inner wall, ruler decoy etc.
Firewall, resource managers, app. Level security,
logging, antivirus, remote backups, egress filters…
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Castle Solution – Extremely Unscalable
IUPUI
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Security Mechanisms
Normally, not a single silver bullet
 Develop multiple layers of defense
 Employ as many layers of defense as needed –
risk, resource profiles
 Castle, moat, drawbridge, mountain-top
lookout, perimeter wall, inner wall, ruler decoy
etc.
 Firewall, resource managers, app. Level
security, logging, antivirus, remote backups,
egress filters…
 Update the patches …Many patches might be
the sign that the problems are deeper.
 Learn from real life security.
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IUPUI
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Today Security
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IUPUI
Authentication is applied sometime only at the
destination
 The attacker can abuse with network
resources
 Network resources (routers, etc.) become
unknowingly attacker’s collaborators by
routing his malicious traffic
 Destination protection becomes an
extremely unscalable problem - each
destination could be under attack from a
very large number of attackers
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Security Analogy
IUPUI
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Maginot Line
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IUPUI
Line of concrete fortifications, which France
constructed along its borders with Germany
and Italy.
 There are 142 ouvrages, 352 casemates, 78
shelters, 17 observatories and around 5,000
blockhouses over all of the Maginot Line.
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Maginot Line
German Invasion
 Attacking on May 10, German forces were
well into France within five days and they
continued to advance until May 24, when
they stopped near Dunkirk.
 When the Allied forces invaded in June 1944
the Line, now held by German defenders, was
again largely bypassed.
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IUPUI
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Two Security Philosophies
“Super Protection”–expensive, unscalable, could be broken.
Prevention power of punishment
IUPUI
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Summary
Networking – tools to improve communications
 Network Architecture: The new Hot Topic
 Evolution of Networking
 Trends in Networking: Users are King
 Design the new Internet based on what we
know now
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IUPUI
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