Presentation given at the e-Science Institute, Edinburgh

1
Challenges for the Future of Networking
Gregor v. Bochmann School of Information
Technology and Engineering (SITE) University of
Ottawa Canada
http//www.site.uottawa.ca/bochmann/talks/FutureN
etworking

• Presentation given at the e-Science Institute,
  Edinburgh
• September 14, 2006

2
Abstract

• The technical foundations for the Internet were
  developed more than 30 years ago. Since over 10
  years, it has developed into a general
  communication infrastructure used by people and
  industry for a variety of applications. While
  e-mail and the Web were first the most important
  applications, newer developments have introduced
  wireless communication and new applications,
  including multimedia, e-commerce, etc. Certain
  applications, e.g. in the area of e-science, have
  extreme requirements in terms of bandwidth or
  delay that cannot be provided by the current
  Internet. - This talk will give a personal view
  of the challenges that must be faced for the
  future of the Internet and the distributed
  applications using it, including managerial and
  technical aspects. Some of these issues are (1)
  the integration of wireless LANs and ad-hoc
  networks with the wired network, (2) fast optical
  switching, (3) user-empowered network management,
  (4) security and trust management, (5) standards
  for distributed applications (e.g. Service
  Oriented Architecture) and (6) ubiquitous
  computing. The talk will provide a general
  discussion of these issues and present certain
  examples of innovative applications.

3
Overview

• The current Internet and applications
• Research management - Grand Challenges
• Research issues in networking
• Optical networks (the physical level)
• Issues for distributed applications
• Conclusions

4
Internet Some Characteristics

• Packet switching
• Buffered in each router or switch (delay)
• IP connection-less
• Logically simple, but requiring address look-up
  for each packet
• Connection-oriented service allows for more
  efficient switching, e.g. new MPLS technology
• There are not enough addresses. Solutions
• use of internal addresses and address translation
  (NAT) however, internal addresses are not
  reachable
• or better use IPv6
• TCP controls flow between end-systems
• Provides reliable information flow
• Many applications need a logical connection
  between processes running in different hosts
• Not suitable for interactive voice or video
  traffic (retransmission introduces delays)
• Not suitable for very large bandwidths (order of
  Gbps)
• UDP non-reliable alternative to TCP

5
Some extreme applications

• Large bandwidth and low delay Video
  teleconference (e.g. round-trip delay of 0.1 sec
  at 10 000 km)
• Need for multicasting video broadcasting (e.g.
  10 Mbps to 10 000 users 100 Gbps)
• Extreme large bandwidth e.g. 10 Gbps for
  e-science applications
• Extremely low delays tele-manipulation (e.g. eye
  surgery training) distributed music ensemble
• Ad hoc networking (without fixed infrastructure)
• people in local meeting
• Sensor networks (large number of sensors, low
  battery life, may fail)

6
Existing communications infrastructures

• Terrestrial transmission infrastructures
• Optical fibres
• Wavelength division multiplexing (each wavelength
  typically 10 Gbps)
• For transmission, data is converted (from the
  electrical domain) into the optical domain (and
  back, by the receiver)
• 10 Gbps is too much for most applications, it
  must be shared
• Bandwidth sharing for telephony (end-to-end flows
  of fixed bandwidth, not packet switching)
• Sonet or SDH (time division multiplexing)
• ATM (cell switching)
• Packet switching may be used for this purpose
  (switching in the electrical domain)
• Packet switch could use 10 Gbps wavelength, or a
  fraction provided by SDH
• Time sharing through photonic switching, e.g.
  burst switching
• Cellular networks (designed for telephony)
• Fixed wireless networks (WIFI)

7
Network management and scalability

• Need for interworking between different domains
  (subnetworks belonging to different
  organizations)
• Limited visibility
• Service level agreements (static dynamic)
• Large number of (scalability)
• Domains
• Routers / switches
• Host computers
• Communicating devices (terminals, phones, TVs,
  kitchen stoves, etc.)
• Security and reliability
• A faulty behavior of a single router should only
  have local impact idem for failures

8
RD - a long path From new idea to market place

• Typical time 20 years
• Example Modeling distributed systems by state
  transition diagrams
• 1969 Bartlett describes a communication protocol
  with finite state machines (FSM)
• 1976 First version of SDL includes FSM notation
• 1977 Bochmann and Gecsei propose Extended FSMs
  for modeling communication protocols
• 1980ies Standardization of formal description
  techniques (FDTs) by ISO and ITU, including SDL
  university-based tool development
• 1987 Harel proposes State Charts (including
  certain extensions of above notations)
• 1990ies Commercial development of software tools
  supporting these notations
• 1995 ? Unified Modeling Language (UML) defined
  by OMG
• Around 2005 Integration between SDL and UML
  Version 2

9
The research planning process (A)

• Funding of research and development
• By industry (internal or external research)
• Objective improve competitiveness
• Better products
• Better development and production methods
• Only larger companies perform longer term
  research and planning
• By government organizations (industrial and
  university research)
• Improve competitiveness of country
• Competent people
• Improve global competitiveness of local industry
• Development of Intellectual Property (IP) to be
  used by local industry
• Difficulty of prioritizing the different fields
  of science and technology
• Give equal chances to all disciplines ?
• Declare certain fields as  national priority  ?
• Let industry buy-in for joint government-industry
  funding programs

10
The research planning process (B)

• Community-based research planning
• Consensus building through mailing lists,
  discussions at workshops / conferences, research
  collaborations
• Examples
• The UK Grand Challenges a perspective on
  long-term basic and applied research
• NSF (USA) Workshop on Overcoming Barriers to
  Disruptive Innovation in Networks
• Research program of E-NEXT (a EU - FP6 Network of
  Excellence)
• CoNEXT conference in Toulouse, Oct. 2005
  http//dmi.ensica.fr/conext/
• Canadian research network on Agile All-Photonic
  Networks (AAPN, funded by NSERC and 6 industrial
  partners)

11
Grand Challenges (defined in the UK)

• See http//www.ukcrc.org.uk/grand_challenges/index
  .cfm
• Definition of a Grand Challenge
• A grand challenge should be defined as to have
  international scope, so that contributions by a
  single nation to its achievement will raise our
  international profile.
• The ambition of a grand challenge can be far
  greater than what can be achieved by a single
  research team in the span of a single research
  grant.
• The grand challenge should be directed towards a
  revolutionary advance, rather than the
  evolutionary improvement of legacy products that
  is appropriate for industrial funding and
  support.
• The topic for a grand challenge should emerge
  from a consensus of the general scientific
  community, to serve as a focus for
  curiosity-driven research or engineering
  ambition, and to support activities in which they
  personally wish to engage, independent of funding
  policy or political considerations. (Note the
  quotes, here and in subsequent slides, indicate
  that the text is copied from the source
  documentation)
• The following two slides are from Robin Milners
  talk A scientific horizon for computing at the
  World Congres 2004 of the International
  Federation for Information Processing (IFIP),
  held in Toulouse.

12
Grand Challenge Exercise
13
UK Grand Challenge Proposals

• Note No GC is dedicated to networking issues

14
Ubiquitous Computing Grand
Challenge

• Combination of GC 2 and GC 4
• See http//www-dse.doc.ic.ac.uk/Projects/UbiNet/GC
  /index.html
• Objective We propose to develop scientific
  theory and the design principles of Global
  Ubiquitous Computing together, in a tight
  experimental loop.
• Engineering challenges
• design devices to work from solar power, are
  aware of their location and what other devices
  are nearby, and form cheap, efficient, secure,
  complex, changing groupings and interconnections
  with other devices
• engineer systems that are self-configuring and
  manage their own exceptions
• devise methods to filter and aggregate
  information so as to cope with large volumes of
  data, and to certify its provenience.
• business model for ubiquitous computing, and
  other human-level interactions.

15
Ubiquitous Computing Grand
Challenge (ii)

• Scientific challenges
• discover mathematical models for space and
  mobility, and develop their theories devise
  mathematical tools for the analysis of dynamic
  networks
• develop model checking, as well as techniques to
  analyse stochastic aspects of systems, as these
  are pervasive in ubiquitous computing
• devise models of trust and its dynamics
• design programming languages for ubiquitous
  computing.
• A comment It is not clear where in the context
  of ubiquitous computing Networking stops and
  Computing starts. In fact, networking involves
  much distributed systems management (including
  databases) and for the Internet applications,
  the application layer protocols are just as
  important as (if not more than) the underlying
  networking protocols.
• Note Milner has developed a new description
  formalism Bigraphs for Mobile Processes
• ( see http//www.cl.cam.ac.uk/users/rm135/ )

16
Research topics in Networking

• Architectural levels of Networking Technology
• a narrow-waisted hourglass model

Network service

• Issues
• Network layer
• new wireless technologies cellular, LAN, PAN,
  ad-hoc, sensor, etc.
• Integration with wire-line Internet
• Higher bandwidth
• Inter-layer control and management according to
  application needs
• Physical layer technology push
• Faster electronic components, e.g. 10 Gbps
  Ethernet
• Fast optical switching
• Trend IP over Dense Wavelength Division
  Multiplexing (DWDM) elimination of intermediate
  layers of ATM, SONET however, it may be IP over
  MPLS over DWDM.
• Application layer
• many new applications importance of multimedia
  application will increase
• New protocols for organizing applications Web
  Services, Grid, peer-to-peer
• New ways for identifying and searching services,
  including concern for security and trust

17
Overcoming Barriers to Disruptive Innovation in
Networks

• Workshop organized by NSF (USA)
• Overcoming Barriers to Disruptive Innovation in
  Networking (Jan. 2005)
• see http//www.arl.wustl.edu/netv/noBarriers_final
  _report.pdf
• Starting point The Internet is ossified
  Adopting a new architecture not only requires
  modifications to routers and host software, but
  given the multi-provider nature of the Internet,
  also requires that ISPs jointly agree on that
  architecture. The need for consensus is doubly
  damning not only is agreement among the many
  providers hard to reach, it also removes any
  competitive advantage from architectural
  innovation. This discouraging combination of
  difficulty reaching consensus, lack of incentives
  for deployment, and substantial costs of
  upgrading the infrastructure leaves little hope
  for fundamental architectural change.

18
NSF workshop (ii)

• Requirements for the new Internet
• Minimize trust assumptions the Internet
  originally viewed network traffic as
  fundamentally friendly, but should view it as
  adversarial
• Enable user choice the Internet was originally
  developed independent of any commercial
  considerations, but today the network
  architecture must take competition and economic
  incentives into account
• Allow for edge diversity the Internet originally
  assumed host computers were connected to the
  edges of the network, but host-centric
  assumptions are not appropriate in a world with
  an increasing number of sensors and mobile
  devices
• Design for network transparency the Internet
  originally did not expose information about its
  internal configuration, but there is value to
  both users and network administrators in making
  the network more transparent and
• Meet application requirements the Internet
  originally provided only a best-effort packet
  delivery service, but there is value in enhancing
  (adding functionality to) the network to meet
  application requirements.
• Identified 7 areas of research (see next slides)

19
7 research areas

• Security
• Economic incentives
• Address binding
• End-host assumptions
• User-level route choice
• Control and management
• Meeting application requirements
• 
  
• 
  (see next slides)

20
Security

• Problem indications
• traffic must be viewed as adversarial rather
  than cooperative
• To take one example, a single mistyped command
  at a router at one ISP recently caused
  widespread, cascading disruption of Internet
  connectivity across many of its neighbors.
• Benefits of better security
• improve network robustness through protocols
  that work despite misbehaving participants,
• enable security problems to be addressed quickly
  once identified,
• isolate ISPs, organizations, and users from
  inadvertent errors or attacks
• prevent epidemic-style attacks such as worms,
  viruses, and distributed denial of service
• enable or simplify deployment of new high-value
  applications and critical services that rely on
  Internet communication such as power grid
  control, on-line trading networks, or an Internet
  emergency communication channel and
• reduce lost productivity currently aimed at
  coping with security problems via patching holes,
  recovering from attacks, or identifying
  attackers.

21
Security (ii)

• Interesting architectural approaches
• prevent denial of service by allowing a receiver
  to control who can send packets to it
• making firewalls a fully recognized component of
  the architecture instead of an add-on that is
  either turned off or gets in the way of deploying
  new applications. A clean specification for
  security that makes clear the balance of
  responsibility for routers, for operating systems
  and for applications can move us from the
  hodge-podge of security building blocks we have
  today to a real security architecture
• A careful design of mechanisms for identity can
  balance, in an intentional way rather than by
  accident, the goals of privacy and
  accountability. Ideally, the design will permit
  us to apply real world consequences (e.g. legal
  or financial) for misbehavior.

22
Economic incentives

• Proposition
• A future design for an Internet should take into
  account that a network architecture induces an
  industry structure, and the economic structure of
  that industry. The architecture can use user
  choice (to impose the discipline of competition
  on the players), indications of value flow (to
  make explicit the right direction of payment
  flow), and careful attention to what information
  is revealed and what is kept hidden (to shape the
  nature of transactions across a competitive
  boundary).

23
Address binding

• Problem with IP addresses
• There are not enough solution IPv6
• They serve as machine identity (instead of only
  identifying the network attachment point, the
  location)
• this leads to difficulties for mobile devices
  (e.g. Mobile IP routing is not straightforward
  IP address changing dynamically)
• IP address (as machine identifier) also used for
  security
• Proposed solution approaches
• Host Identity Protocol
• It provides secure host identification
• Routing is based on IP addresses that are treated
  only as ephemeral locators
• end-points (as equated with physical machines
  or operating systems) need not have any globally
  known identity at all. Instead, application level
  entities have shared identities , and higher
  level name spaces such as a redesigned DNS are
  used to give global names to services, so that
  they can be found.

24
End host assumptions

• Issues with sensor networks
• sensors may be intermittently connected
• routing may be based on data values
• Solution approaches Overlay networks
• Overlay for realizing special routing functions,
  e.g. diffusion routing
• Overlay for delay-tolerant routing (e.g. for
  e-mail also allowing access in a variety of
  impoverished and poorly connected regions )

25
User-level route choice

• Objectives increase the users choice and
  introduce more competition
• Instead of applying a "one-size-fits-all"
  policy to their traffic, ISPs could perform
  routing and traffic engineering based upon the
  user traffic preferences  offer unique policies
  such as keeping all traffic within the
  continental United States for security reasons.
• This selection creates a more complex economic
  environment it offers potential rewards in user
  choice and competition, but requires solutions to
  issues of accounting, pricing, billing, and
  inter-ISP contracts.

26
Control and management

• Statement Management of the Internet is very
  complex (for all parties involved)
• Solutions not clear (there are references to
  ongoing work)
• One problem limited visibility of internal
  parameters from outside the network (opaqueness)
• A network should support communication of
  operationally relevant information to each other.
  Such information could be aggregated and
  analyzed, thereby facilitating load balancing,
  fault diagnosis, anomaly detection, application
  optimization, and other traffic engineering and
  network management functions.
• One needs a compromise between information hiding
  and visibility for management.

27
Meeting application requirements

• Protocol layer architecture is a narrow-waisted
  hourglass model
• Additional requirements
• QoS control, multicast, anycast,
  policy-based routing, data caching
• Possible solutions
• Add more functions to IP layer
• Use overlay networks to provide additional
  functions

28
Some personal comments

• Overlay networks
• Principle A certain number of servers connected
  to the Internet play the role of  virtual
  routers  in the overlay network. Note This is
  the way MBone implements multicasting over the
  current IP Internet service.
• The NSF workshop stresses the use of overlay
  networks for experimentation with new approaches
• Could such architectures present the final
  solution ?
• NO, overlay technology, such as peer-to-peer
  computing, may be useful for certain
  applications, but cannot be a solution for
  building a network
• Existing well-known applications
• Napster and BitTorrent media distribution, and
  other peer-to-peer applications
• Multicasting of multimedia presentations,
  possibly including different quality variants
• A Testbed US-based Planetlab http//planet-lab.or
  g/ see also http//www.arl.wustl.edu/netv/main.ht
  ml

29
Some personal comments (2)

• Lightpaths - Underlay Networks ?
• Experimental research networks provide
  high-bandwidth lightpaths between different
  sites for e-science and other applications that
  require guaranteed high-bandwidth connections.
• For an overview of current applications, see
  http//www.internet2.edu/presentations/fall05/2005
  0920-lambdas-sauver.htm
• User-Controlled Lightpath Provisioning (UCLP)
  allows the e-science users to establish
  lightpaths dynamically through a graphic user
  interface.
• Note UCLP has been initiated in Canada with
  partial funding from Canarie (the Canadian
  research network), see for instance
  http//www.uclp.ca
• These networks make use of user-owned fibers and
  condominium facilities for long-haul transmission
  and switching
• This is not an overlay, but also provides a new
  networking service, independently from the
  existing Internet. The Internet can be built on
  top of it.

30
Some personal comments (3)

• Packets vs. (virtual) connections
• The old debate between packet switching and
  circuit switching (from the 1970ies) is not dead
  !!
• Distinction In packet switching, the header of
  the packet/frame/cell/burst contains the
  destination address in circuit switching, it
  contains a number (label) identifying the circuit
  (in TDM, this number is the timing position).
• MPLS (label switching) provides packet switching
  over dynamically established paths (virtual
  connections)
• Optical lightpaths are connection-oriented. It is
  expected that existing ROADM (Reconfigurable
  optical add/drop multiplexers) technology will be
  widely deployed within a few years see for
  instance http//lw.pennnet.com/Articles/Article_Di
  splay.cfm?SectionARTCLARTICLE_ID203231VERSION_
  NUM1
• An optical lightpath at a given wavelength is
  very large, typically 10 Gbps. Sub-multiplexing
  of a lightpath in the time domain is proposed by
  many research projects
• Sharing between packets or virtual connections ??

31
Some personal comments (4)

• Appearently contradictory approaches
• IP packet-oriented switching
• The concept of virtual connections are natural
  for providing QoS guarantees.
• The lower layers of broadband wireline networks
  appear to use connection-oriented technologies.
• The overlay networks would like to obtain more
  visibility about the performance aspects of the
  underlying IP service.
• Suggestion Maybe there should be more visibility
  at the IP service level about the underlying
  virtual and physical circuits that exist within
  the network and their performance parameters and
  the application should have some choice about the
  routing of its data.

32
Optical networks

• Currently deployed
• optical transmission with DWDM
• Some optical switching
• Note most optical switches convert the optical
  signal into the electrical domain and perform the
  switching in the electrical domain.
• Expected to be deployed
• ROADM used for transparent optical switching in
  the millisecond speed range good for protection
  switching and bandwidth on demand.

33
Burst switching

• Question Can one do packet switching in the
  optical domain (without oeo conversion)?
• At a switching speed of 1 µs, one could switch
  bursts of 10 µs length (typically containing many
  packets)
• Traditional packet switching involves packet
  buffering in the switching nodes. Should one
  introduce optical buffers in the form of delay
  lines?
• The term burst switching originally meant no
  buffering in case of conflict for an output
  port, one of the incoming bursts would be
  dropped.
• Note Burst switching allows to share the large
  optical bandwidth among several virtual
  connections.

34
AAPNAn NSERC Research Network The Agile
All-Photonic Network Project leader David
Plant, McGill UniversityTheme 1 Network
architecturesGregor v. Bochmann, University of
OttawaTheme 2 Device technologies for
transmission and switching
35
AAPN Professors (Theme 1 in red)

• McGill Lawrence Chen, Mark Coats, Andrew Kirk,
  Lorne Mason, David Plant (Theme 2 Lead), and
  Richard Vickers
• U. of Ottawa Xiaoyi Bao, Gregor Bochmann (Theme
  1 Lead), Trevor Hall, and Oliver Yang
• U. of Toronto Stewart Aitchison and Ted Sargent
• McMaster Wei-Ping Huang
• Queens John Cartledge (Theme 3 Lead)
• Note Theme 2 deals with device technologies for
  transmission and switching
• For further information see
  http//www.aapn.mcgill.ca/

36
The AAPN research network

• Our vision Connectivity at the end of the
  street to a dynamically reconfigurable photonic
  network that supports high bandwidth
  telecommunication services.
• Technical approach
• Simplified network architecture (overlaid stars)
• Specific version of burst switching
• Fixed burst size, coordinated switching at core
  node for all input ports (this requires precise
  synchronization between edge nodes and the core)
• See for instance http//beethoven.site.uottawa.ca/
  dsrg/PublicDocuments/Publications/Hall05a.pdf
• Burst switching with reservation per flow
  (virtual connection), either fixed or dynamically
  varying
• See for instance http//beethoven.site.uottawa.ca/
  dsrg/PublicDocuments/Publications/Agus05a.pdf

37
Agile All-Photonic Network

• Provisions sub-multiples of a wavelength
• Large number of edge nodes

Edge node with slotted transmission (e.g. 10
Gb/s capacity per wavelength)
Fast photonic core switch (one space switch
per wavelength)
AAPN
Opto-electronic interface
AAPN
AAPN
Overlaid stars architecture
38
Starting Assumptions

• Avoid difficult technologies such as
• Wavelength conversion
• Optical memory
• Optical packet header recognition and replacement
• Current state of the art for data rates, channel
  spacing, and optical bandwidth
• Simplified topology based on overlaid stars
• Edge based control in small/medium size edge nodes

39
Starting Assumptions (ii)

• No distinction between long-haul and metro
  networks
• Fast optical space switching (lt1 msec)
• Slotted Time Division Multiplexing (TDM) or
  slotted burst switching
• Need for fast compensation of transmission
  impairments (lt1 msec)

40
Bandwidth allocation schemes

• For flows between edge nodes
• Optical wavelength Whole wavelength (for large
  bandwidth flows) like the PetaWeb explored by
  Nortel Networks
• Optical circuit One or several time slots within
  each TDM frame
• Burst switching individual bursts (with or
  without reservation)
• Coordination by controller at core node
• Signaling protocol between edge and core node
  (suitable for metro and long-haul networks)

41
Integration higher layer (MPLS and IP)

• MPLS flows passing through the AAPN
• With N edge nodes, there are N x N links in the
  AAPN (scalability problem for IP routing
  protocol)
• Virtual router star architecture
• OSPF sub-areas
• How to find optimal inter-area route
• (work sponsored
• by Telus)

42
Deployment aspects - Questions

• Long-haul or Metro ?
• connectivity at the end of the street to a
  server farm
• AANP as a backbone network ?
• High capacity (many wavelengths) or low capacity
  (single or few wavelengths) ?
• Multiple core nodes ?
• For reliability
• For load sharing
• Transmission infrastructure ?
• Using dedicated fibers
• Using wavelength channels provided by ROADM
  network

43
Issues forDistributed applications

• Multimedia
• Ubiquitous computing and location-awareness
• Service-oriented architecture and Grid computing
• Making it easy for the end-user
• Scalability peer-to-peer computing
• Related technologies
• Security
• Trust management
• Software development technology

44
Distributed multimedia applications

• The basics are relatively well understood
• Video requires high bandwidth
• Conversational applications require short
  transmission delays
• In many cases, multicasting is required (possibly
  provided through the overlay approach)
• Aspects to be further explored
• Shared virtual environments, e.g. for
  collaborative work or games
• Tactile applications tele-haptics require very
  short delays
• Quality of service management for multiple
  receivers media transcoding

45
Example Locating suitable transcoding servers
(El-Khatib)

• See http//beethoven.site.uottawa.ca/dsrg/PublicDo
  cuments/Publications/ElKh04c.pdf

46
Ubiquitous computing and
location-awareness

• See Grand Challenge
• Example Some issues encountered in our project
  on teleconferencing for mobile users
• Problem In ad-hoc environment (e.g. on a trip)
  find out what devices may be useful to the user
  to establish a video-conference with a friend in
  another country.
• Consider quality of service (QoS) negotiation to
  find most suitable devices according to the
  users preferences and the remote site.
• Assumption User has a PDA that can detect
  through short-range wireless communication (e.g.
  Bluetooth) which devices are available in the
  environment.
• Approach We use a Home Directory to store the
  preferences of the user it must be down-loaded
  into the PDA for processing (it may be a rented
  PDA). See http//beethoven.site.uottawa.ca/dsrg/Pu
  blicDocuments/Publications/ElKh04a.pdf

47
Example Device selection in an ad-hoc environment

48
Example Session mobility and QoS
adaptation

49
Service-oriented architecture and
Grid applications

• Concepts
• RPC for accessing services
• Directory service
• Realizations CORBA, Jini (Java environment)
• WS and SOA use similar concepts
• Use HTTP and SOAP (based on XML)
• Workflow specifications (BPEL, etc.)
• Advantages
• use of HTTP (firewalls)
• programming language independent (like CORBA)

50
Notes on XML

• text-oriented encoding of data structures (based
  on SGML, like HTML)
• used for storage and/or transmission
• Data structure (type) definition in the form of
  DTD or XML Schema
• Developed by WWW Consortium http//www.w3.org/
• Used for a multitude of applications, see for
  instance list of resources at http//www.extensine
  t.com/

51
WS Example applications

• E-commerce
• Historical
• First e-commerce Electronic Data Interchange
  (EDI)
• Standards about data elements required in
  purchase order, invoice, shipping documents, etc.
  
• Standard coding format
• Message transmission over telephone or leased
  lines
• Transition to the use of the Internet
  Development of SOAP (new coding standard based on
  XML)
• Nowadays many new applications and developments
• See Electronic Business using XML
  http//www.ebxml.org/
• OASIS http//www.oasis-open.org/
• Resource sharing
• E-science projects - Grid computing
• Network management, e.g. UCLP (see above)
• Need for common understanding of information
  (semantics)
• Work by the W3C on the Semantic Web
  http//www.w3.org/2001/sw/

52
Making it easy for the end-user

• Everyday use (for our normal day activities)
• Content creation by the end-user
• See It's A Whole New Web (Businessweek)
  http//www.businessweek.com/magazine/content/05_39
  /b3952401.htm

53
Peer-to-peer computing

• Scalability to the millions and more
• Load is shared on a peer-to-peer basis
• Individual servers may come and go
• Robustness of the overall system
• Example of service
• distributed storage and search facility
• Not only applicable to file sharing
• Note this is an overlay system

54
Related technologies

• Security
• Trust management
• Software development technology

55
Security

• Services
• Privacy of message exchanges
• Integrity of messages
• Authentication of users and devices
• Signature with non-repudiation
• Cryptographic technologies
• Secret key encryption
• Public key encryption (RCA, elliptic, etc.)
• Hash functions, etc.
• Secure private and public networks
• Integration of security into application layer
  protocols
• New types of applications
• Electronic cash

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Trust management

• trust is the outcome of observations leading to
  the belief that the actions of another may be
  relied upon, without explicit guarantee, to
  achieve a goal in a risky situation
• -- Greg Elofson
• Key elements
• Observations (experience, interaction)
• Belief (assumption)
• Goal (expectation)
• Without guarantee (risk)
• Subjective

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Trust An example scenario

• Alice visits her friend Bob who lives since a
  year in a foreign country. She wants to invite
  Bob and some of his friends for supper. She does
  not know which restaurant to choose, since she
  wants tasty food, a nice atmosphere and good
  service.
• In her own city, she has experienced many
  restaurants and she knows the restaurants she
  would choose depending on how important food,
  atmosphere and service is for the occasion. She
  trusts these restaurants, based on her past
  experience.
• Now she asks Bob for his experience in order to
  select an appropriate restaurant. She trusts Bob
  for telling her the truth and for evaluating
  restaurants based on similar criteria as herself.
• Then she selects a restaurant with good food,
  because the friends find food more important than
  service. (Note food is the utility to be
  optimized)

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Some observations

• Trust is used for decision making
• Trust means a prediction of the outcome of a
  service invocation
• E.g. based on the experience, we predict that the
  chosen restaurant will provide tasty food.
• Our trust model based on statistics and Bayesian
  estimation http//beethoven.site.uottawa.ca/dsrg/P
  ublicDocuments/Publications/Shi04a.pdf
• The space of possible outcomes usually depends on
  the context in which the trust model is used
• Trust is the estimation of a probability
  distribution over the possible outcomes of
  experiences
• Our own experience is more reliable than the
  experience of peers, however, peers may have more
  experiences than we.
• Question can we trust the recommendations of
  others ?
• Our recommendation evaluation algorithm
  http//beethoven.site.uottawa.ca/dsrg/PublicDocume
  nts/Publications/Shi05a.pdf
• Weight each recommendation according to the trust
  in the recommender
• The trust in the recommender will decrease if a
  given recommendation is unfair
• How can one determine the fairness of a
  recommendation ??
• How detailed should the trust model be ?
• Should one distinguish different dimensions, e.g.
  food, atmosphere and service, or simply have one
  evaluation category, e.g. the restaurant being
  either excellent, good, bad or very bad ?
• Is it possible to determine the expected error of
  predictions?

59
Transactions based on trust

• Existing access control model for mobile users
  Autonomic Distributed Authorization Middleware

60
Systematic development of distributed
applications

• UK Grand Challenge Dependable Systems Evolution
  
• use of assertions for defining component
  requirements
• verifying compiler as a goal
• Personal comment Is this the right approach ??
• UML - formalizing its semantics
• Work in Ottawa
• Defining requirements by scenarios (see
  http//beethoven.site.uottawa.ca/dsrg/PublicDocume
  nts/Publications/Sand05a.pdf )
• Using notations of Activity Diagrams or Use Case
  Maps (UCMs) (see http//www.site.uottawa.ca/damyo
  t/pub/index.shtml )
• Define semantics of these languages based on
  Coloured Petri nets
• Consideration of performance parameters (see
  http//www.sce.carleton.ca/rads/puma/ )
• Relationship to workflow modeling, transaction
  processing, BPEL

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Conclusions

• Networking implies different system layers
• physical transmission
• network services and their management
• distributed applications
• There is technology push (higher bandwidth,
  wireless transmission, computing power) and
  application pull (after e-mail and WWW IP
  telephony and conferencing, VOD, e-commerce,
  e-society)
• There are many interesting topics of research
  relevant to the future of networking