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/FutureNetworking
Presentation given at the e-Science Institute, Edinburgh
September 14, 2006
Gregor v. Bochmann, University of Ottawa
Future of Networking, 2006
1
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, ecommerce, 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.
Gregor v. Bochmann, University of Ottawa
Future of Networking, 2006
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Overview
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The current Internet and applications
Research management - Grand
Challenges
Research issues in networking
Optical networks (the physical level)
Issues for distributed applications
Conclusions
Gregor v. Bochmann, University of Ottawa
Future of Networking, 2006
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Internet: Some Characteristics

Packet switching

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Buffered in each router or switch (delay)
IP : connection-less
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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:

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TCP : controls flow between end-systems

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use of internal addresses and address translation (NAT); however, internal
addresses are not reachable
or better: use IPv6
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
Gregor v. Bochmann, University of Ottawa
Future of Networking, 2006
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Some extreme applications

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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
Gregor
v. Bochmann,
University
of Ottawa
Future of Networking, 2006
5
Existing communications
infrastructures

Terrestrial transmission infrastructures

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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)
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Packet switching may be used for this purpose (switching in the electrical
domain)
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Sonet or SDH (time division multiplexing)
ATM (cell switching)
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)
Gregor v. Bochmann, University of Ottawa
Future of Networking, 2006
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Network management and scalability

Need for interworking between different
domains (subnetworks belonging to different
organizations)
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Limited visibility
Service level agreements (static – dynamic)
Large number of …

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(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
Gregor v. Bochmann, University of Ottawa
Future of Networking, 2006
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R&D - a long path:
From new idea to market place

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Typical time : 20 years
Example: Modeling distributed systems by state transition
diagrams
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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
Gregor v. Bochmann, University of Ottawa
Future of Networking, 2006
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The research planning process (A)

Funding of research and development

By industry (internal or external research)

Objective: improve competitiveness

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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

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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

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Give equal chances to all disciplines ?
Declare certain fields as « national priority » ?
Let industry buy-in for joint government-industry funding programs
Gregor v. Bochmann, University of Ottawa
Future of Networking, 2006
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The research planning process (B)

Community-based research planning

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Consensus building: through mailing lists, discussions
at workshops / conferences, research collaborations
Examples:

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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)
Gregor v. Bochmann, University of Ottawa
Future of Networking, 2006
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Grand Challenges (defined in the
UK)


See http://www.ukcrc.org.uk/grand_challenges/index.cfm
“Definition of a Grand Challenge

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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.
Gregor v. Bochmann, University of Ottawa
Future of Networking, 2006
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Grand Challenge Exercise
Gregor v. Bochmann, University of Ottawa
Future of Networking, 2006
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UK Grand Challenge Proposals
Note: No GC is dedicated to networking issues
Gregor v. Bochmann, University of Ottawa
Future of Networking, 2006
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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. “
Gregor v. Bochmann, University of Ottawa
Future of Networking, 2006
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Ubiquitous Computing
Grand Challenge (ii)

“Scientific challenges:
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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/ )
Gregor v. Bochmann, University of Ottawa
Future of Networking, 2006
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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.

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Inter-layer control and management according to application needs
Physical layer: technology push

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Integration with wire-line Internet
Higher bandwidth
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

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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
Gregor v. Bochmann, University of Ottawa
Future of Networking, 2006
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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. “
Gregor v. Bochmann, University of Ottawa
Future of Networking, 2006
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NSF workshop (ii)

Requirements for the new Internet:
 “ Minimize trust assumptions: the Internet originally viewed network

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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)
Gregor v. Bochmann, University of Ottawa
Future of Networking, 2006
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7 research areas:
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Security
Economic incentives
Address binding
End-host assumptions
User-level route choice
Control and management
Meeting application requirements
(see next slides)
Gregor v. Bochmann, University of Ottawa
Future of Networking, 2006
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Security

Problem indications

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“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
1.
2.
3.
4.
5.
6.
“ 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. “
Gregor v. Bochmann, University of Ottawa
Future of Networking, 2006
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Security (ii)

Interesting architectural approaches:

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“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. “
Gregor v. Bochmann, University of Ottawa
Future of Networking, 2006
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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). “
Gregor v. Bochmann, University of Ottawa
Future of Networking, 2006
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Address binding

Problem with IP addresses

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There are not enough – solution: IPv6
They serve as machine identity (instead of only identifying the
network attachment point, the location)

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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
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Host Identity Protocol

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
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. “
Gregor v. Bochmann, University of Ottawa
Future of Networking, 2006
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End host assumptions

Issues with sensor networks
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sensors may be intermittently connected
routing may be based on data values
Solution approaches: Overlay networks

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Overlay for realizing special routing functions,
e.g. diffusion routing
Overlay for delay-tolerant routing (e.g. for email; also allowing “access in a variety of
impoverished and poorly connected regions “)
Gregor v. Bochmann, University of Ottawa
Future of Networking, 2006
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User-level route choice

Objectives: increase the user’s choice and
introduce more competition

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“ 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. “
Gregor v. Bochmann, University of Ottawa
Future of Networking, 2006
25
Control and management
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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.
Gregor v. Bochmann, University of Ottawa
Future of Networking, 2006
26
Meeting application requirements


Protocol layer architecture is a narrowwaisted hourglass model
Additional requirements:


IP Network
service
“QoS control, multicast, anycast,
policy-based routing, data caching …”
Possible solutions:


Add more functions to IP layer
Use overlay networks to provide additional functions
Gregor v. Bochmann, University of Ottawa
Future of Networking, 2006
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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.org/; see also

http://www.arl.wustl.edu/netv/main.html
Gregor v. Bochmann, University of Ottawa
Future of Networking, 2006
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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.

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For an overview of current applications, see
http://www.internet2.edu/presentations/fall05/20050920-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.
Gregor v. Bochmann, University of Ottawa
Future of Networking, 2006
29
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_Display.cfm?Section=ARTCL&ARTICLE_ID=203231&VERSION_NUM=1

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 ??
Gregor v. Bochmann, University of Ottawa
Future of Networking, 2006
30
Some personal comments (4)

Appearently contradictory approaches

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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.
Gregor v. Bochmann, University of Ottawa
Future of Networking, 2006
31
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.
Gregor v. Bochmann, University of Ottawa
Future of Networking, 2006
32
Burst switching

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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.
Gregor v. Bochmann, University of Ottawa
Future of Networking, 2006
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AAPN
An NSERC
Research Network
The Agile
All-Photonic Network
Project leader: David Plant, McGill University
Theme 1: Network architectures
Gregor v. Bochmann, University of Ottawa
Theme 2: Device technologies for transmission and
switching
Gregor v. Bochmann, University of Ottawa
Future of Networking, 2006
34
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/
Gregor v. Bochmann, University of Ottawa
Future of Networking, 2006
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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
Gregor v. Bochmann, University of Ottawa
Future of Networking, 2006
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Agile All-Photonic Network
Edge node with slotted transmission
(e.g. 10 Gb/s capacity per wavelength)
Fast photonic core switch
(one space switch per wavelength)
Opto-electronic interface
- Provisions submultiples of a
wavelength
- Large number of
edge nodes
Overlaid stars architecture
Future of Networking, Lausanne, 2005
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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
Gregor v. Bochmann, University of Ottawa
Future of Networking, 2006
38
Starting Assumptions (ii)




No distinction between long-haul and metro
networks
Fast optical space switching (<1 msec)
Slotted Time Division Multiplexing (TDM) or
slotted burst switching
Need for fast compensation of transmission
impairments (<1 msec)
Gregor v. Bochmann, University of Ottawa
Future of Networking, 2006
39
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)
Gregor v. Bochmann, University of Ottawa
Future of Networking, 2006
40
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)
Gregor v. Bochmann, University of Ottawa
Future of Networking, 2006
41
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)
?
Multiple core nodes ?
or low capacity
(single or few wavelengths)




For reliability
For load sharing
Transmission infrastructure ?


Using dedicated fibers
Using wavelength channels provided by ROADM network
Gregor v. Bochmann, University of Ottawa
Future of Networking, 2006
42
Issues for
Distributed 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
Gregor v. Bochmann, University of Ottawa
Future of Networking, 2006
43
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
Gregor v. Bochmann, University of Ottawa
Future of Networking, 2006
44
Example: Locating suitable
transcoding servers (El-Khatib)
See http://beethoven.site.uottawa.ca/dsrg/PublicDocuments/Publications/ElKh04c.pdf
Gregor v. Bochmann, University of Ottawa
Future of Networking, 2006
45
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 user’s 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/PublicDocuments/Publications/ElKh04a.pdf
Gregor v. Bochmann, University of Ottawa
Future of Networking, 2006
46
Example: Device selection in an
ad-hoc environment
Alice
Bob’s HDA
2
1
7
3
Internet
6
PA
(PDA)
Alice’s HDA
5
4 4
5
4
7
Gregor v. Bochmann, University of Ottawa
5
4 5
5 4
5
4
Future of Networking, 2006
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Example: Session mobility
and QoS adaptation
Personal Agent
Communication Agent
User Profile
QoS
Negotiation
and Selection
Agent
Service
Registry
User
Context
Agent
Service
Discovery
Agent
Gregor v. Bochmann, University of Ottawa
Future of Networking, 2006
48
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)
Gregor v. Bochmann, University of Ottawa
Future of Networking, 2006
49
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.extensinet.com/
Gregor v. Bochmann, University of Ottawa
Future of Networking, 2006
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WS: Example applications

E-commerce:

Historical:

First e-commerce: Electronic Data Interchange (EDI)






See “Electronic Business using XML” http://www.ebxml.org/
OASIS http://www.oasis-open.org/
Resource sharing



Transition to the use of the Internet: Development of SOAP (new coding
standard based on XML)
Nowadays: many new applications and developments


Standards about data elements required in purchase order, invoice, shipping
documents, etc.
Standard coding format
Message transmission over telephone or leased lines
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”
Gregor v. Bochmann, University of Ottawa
http://www.w3.org/2001/sw/
Future of Networking, 2006
51
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
Gregor v. Bochmann, University of Ottawa
Future of Networking, 2006
52
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
Gregor v. Bochmann, University of Ottawa
Future of Networking, 2006
53
Related technologies



Security
Trust management
Software development technology
Gregor v. Bochmann, University of Ottawa
Future of Networking, 2006
54
Security

Services





Cryptographic technologies






Privacy of message exchanges
Integrity of messages
Authentication of users and devices
Signature with non-repudiation
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
Gregor v. Bochmann, University of Ottawa
Future of Networking, 2006
55
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
Gregor v. Bochmann, University of Ottawa
Future of Networking, 2006
56
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)
Gregor v. Bochmann, University of Ottawa
Future of Networking, 2006
57
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/PublicDocuments/Publications/Shi04a.pdf



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/PublicDocuments/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 ?


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
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?
Gregor v. Bochmann, University of Ottawa
Future of Networking, 2006
58
Transactions based on trust
Existing access control model for mobile users: “Autonomic
Distributed Authorization Middleware”
Gregor v. Bochmann, University of Ottawa
Future of Networking, 2006
59
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/PublicDocuments/Publications/Sand05a.pdf )

Using notations of Activity Diagrams or Use Case Maps (UCMs)
http://www.site.uottawa.ca/~damyot/pub/index.shtml )


(see
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
Gregor v. Bochmann, University of Ottawa
Future of Networking, 2006
60
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
Gregor
v. Bochmann, University of Ottawa
Future of Networking, 2006 61

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