Transcript View File - University of Engineering and Technology, Taxila

Lecture 1
Advance Topics in
Networking
McGraw-Hill Technology Education
Copyright © 2006 by The McGraw-Hill Companies, Inc. All rights reserved.
Lecture 1: Introduction
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Course Goals
Course Topics
Student Introduction
Research Paper Review
Hints on Reading a Paper
Reviewers Guidelines
Paper Review Guidelines
First Papers: For this week
Course Goals
• Critical examination of current topics in networking
– What assumptions are no longer valid
– What are new research problems to look at
• Understanding solutions in context
– Goals
– Assumptions
• Learn how to do research
– Paper review, writing and presentation
• Appreciate what is good research
– Problem selection
– Solution and Research Methodology
– Presentation
• Apply what you learn in this class
Course Topics
• Intranet / internet routing
• Traffic engineering
• Network diagnosis and rectification
• Network Host Security
• Network Anomaly Detection
• Network Traffic Classification
• Peer to Peer Networks
• Privacy and anonymity
• Network measurement
• Future directions in Internet architecture
• Cellular Networks
• Ad hoc and Infrastructure Networks
Student Introduction
• Please introduce yourself
– Name, research area, …
• Say a few words about what you like to learn about
networking
– Email me if there is any other specific topic not already
included in the topics slide to be covered in this class
• What you think are “un-solved” problems in computer
networks
• What kind of help is required for writing your own
research papers
• How many students can group together for
presentations, projects and research groups
• How can we help in your research
Research Paper Review
• Read at least one or two papers on the subject for
writing good reviews.
• Read some of the associated literature (by following
some of the citations provided in the paper).
• You are free to pick a review format, but a common
format is as follows.
– First, summarize what you understood of the paper in 1-2
paragraphs.
– Then, point out what you liked about the paper.
– After that, discuss the main flaws (if any) that you found in
the paper.
– Follow it with detailed suggestions for improving the paper
(e.g. suggest experiments, other approaches to consider,
better ways to present data etc.).
Hints on Reading a Paper
• Three stage approach
1. Read quickly in 5-10minutes
2. Read with greater care; ignore proofs
3. Deconstruct paper; question all assumptions
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Stage 1: 5-10 minute read
• Read title, abstract, introduction, section
headings, conclusion, reference list.
• Look for “5 C’s”
– Category: What type of paper is it?
– Context: Where does it fit in?
– Correctness: Do assumptions make
sense?
– Contributions: What are the main ones?
– Clarity: Is it well-written?
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Stage 2: Read with Care
• Spend about an hour re/reading paper in
detail
• Try to understand the “story”
• Summarize the main concepts
• Identify main supporting evidence
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Stage 3: Deconstruct the paper
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This can take one or more hours
Understand every proof
Question every assumption
Identify missing references
Why was the paper written this way?
How else could the paper have been
written?
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Reviewers Guidelines
• Paper reviews should be submitted at
the beginning of every class in
hardcopies.
• If you cannot attend the class, please
email your review to
[email protected]
• Cell: 0334-5488-733
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Proxy: web.uettaxila.edu.pk
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Port: 8765
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Login: guest1 Pass: guest1
• http://web.uettaxila.edu.pk/cms/msATNau09/
Paper Review Guidelines
• Paper Summary (3-5 sentences)
• What are the major problem(s) or issue(s)
addressed by the paper?
• Are they important and/or interesting?
• Why?*
• What are the main results of this paper?
• Are they useful or significant?
• Will anyone benefit from it?
• Will it be used by others in their research?
• Does it open up new areas or resolve an
important open issue?
Paper Review Guidelines
• What is the approach/methodology in this
paper?
• Comment on its degree of novelty, creativity,
and technical depth.
• How would you use them for other studies?
• Strength: What are the major strengths of the
paper?
• Weaknesses: What are the major flaws of the
paper?
• The flaws can be any simplications made that
may significantly affect the results.
Paper Review Guidelines
• Assumptions: What are the inherent
assumptions or the models used in the paper
(if any)? Are they still valid today?
• Future work: What are the avenues for future
work or follow-up studies?
• If you are asked to work on the same problem
today, how would you do differently?
• Detailed Comments: Please provide detailed
comments that will be helpful for further
assessing the paper.
First papers: For this week
Read deep
1. The Design Philosophy of the DARPA
Internet Protocols - Clark, 1988
2. End-to-End Arguments in System Design Saltzer, Reed and Clark, 1984
The green highlighted paper above is to
be reviewed by the students as home
assignment 1
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The Design Philosophy of the DARPA Internet Protocols
Goal 0: An “effective” technique for multiplexed utilization of existing
interconnected networks.
Goal 1: Internet communication must continue despite loss of
networks or gateways.
Goal 2: The Internet must support multiple types of communication
service.
Goal 3: The Internet architecture must accommodate a variety of
networks [underneath].
Goal 4: The Internet architecture must permit distributed
management of its resources.
Goal 5: The Internet architecture must be cost effective.
Goal 6: The Internet architecture must permit host attachment with
a low level of effort.
Goal 7: The resources used in the internet architecture must be
accountable.
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Goal 0: An effective technique for multiplexed
utilization of existing interconnected networks
• Leads to: Different networks connected
together by packet switched, store-andforward routers/gateways
• Why interconnect existing networks and not
design a new overall network from scratch?
• Why was packet switching picked for
multiplexing? What were the choices?
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Goal 1: Internet communication must continue
despite loss of networks or gateways.
“Entities should be able to continue communicating without having
to reestablish or reset the high level state of their conversation”
“The architecture [should] mask competely any transient failure”
Leads to:
1. “Fate-sharing” model - only lose communication
state if the end-host is lost.
2. Stateless packets switches => datagrams
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What alternative design could there be?
How does the Internet do this?
To what extent does it accomplish it?
To what extent is it possible?
Could a “dedicated” new network be more reliable?
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Other goals
Goal 4: The Internet architecture must permit
distributed management of its resources
– To what extent does it accomplish this?
Goal 5: The Internet architecture must be cost
effective.
– Is it?
Goal 7: The resources… must be accountable
– What dos this mean?
– What would such a network look like?
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Minimum Assumptions of interconnected networks
1. Can transport a datagram
2. …of reasonable size
3. …with reasonable chance of delivery
Interesting comments:
• Reliability and qualities of service were not
built in because they would require too
much change.
• Datagram as a building block, not as a
service.
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Other discussion questions
1. Originally TCP+IP were joined, but
were later split. Why was that?
2.
“It proved more difficult than first hoped to provide
multiple types of service without explicit support
from the underlying network”
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Why is that? What has happened since?
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Other discussion questions
• Interesting comment: “The most
important change in the Internet…will
probably be the development of a new
generation of tools for management of
resources...”
– Why has distributed management been so
hard?
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Other discussion questions
• Claim: Correctness of a protocol can be
automated, whereas performance is
harder to understand and often dictated
by the operating system.
• At the time, simulation was hard/poor.
• Analytical tools lacking.
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Author’s conclusion
• “Datagram” good for most important
goals, but poor for the rest of the goals.
• Processing packets in isolation,
resource management, accountability all
hard.
• Proposes flows and soft-state for the
future.
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The End
Questions?
McGraw-Hill Technology Education
Copyright © 2006 by The McGraw-Hill Companies, Inc. All rights reserved.