Networking Research: Trends and Issuessce2.umkc.edu/csee/dmedhi/presentation/dm-netedu-presentation-feb...2 NeTReL, Networking & Telecommunications Research DM, February 2007, p.3
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DM, February 2007, p.1NeTReL, Networking & Telecommunications Research Lab
Networking Research: Trends and Issues
Deep MedhiNetworking & Telecommunication Research Lab (NeTReL)
Computer Science & Electrical Engineering DepartmentSchool of Computing & Engineering
University of Missouri-Kansas City, USAhttp://www.csee.umkc.edu/~dmedhi
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Outline
Review: CSTB 2001 ReportBroad Categories for Networking ResearchTrendsSome Historical ExamplesIssues
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CSTB2001 Report“Looking Over the Fence at Networks: A Neighbor's View of Networking Research”– By Computer Science & Telecommunications
Board (CSTB), National Research Council of US
• Published in 2001 by National Academy Press, available http://books.nap.edu/html/looking_over_the_fence/report.pdf
• Addresses Three Broad Areas
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CSTB 2001 report: First Area
Measuring: Understanding the Internet Artifact– Challenge of Scale
• How to infer based on incomplete knowledge of configuration
• How to soundly sample network traffic, and validity of sampling approach
– Measurement Infrastructure• Deployment and operational challenges
– Nontechnical factors• Compose of production commercial systems
– E.g., Confidentiality and privacy of data
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CSTB 2001 Report: Second Area
Modeling: New Theory for Networking– Performance:
• E.g., What sort of change in the scale and traffic pattern lead to a performance meltdown?
• Theoretical foundations in flow-level modeling, aggregration/deaggregation, micro/macro level interaction
– Beyond Performance:• Concern for manageability, reliability, robustness, and
evolvability—new basic understanding and theory– Applying Theoretical Techniques to Networking
• Understand convergence properties• New routing algorithms taking real-world constraints
(e.g. absence of complete information)
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CSTB 2001 Report: Third Area
Making disruptive prototypes (“Innovator’s Dilemma”) “A Disruptive technology can do a few things very well but may not do some very well compared to present technology”
• Example, RISC architecture (from computer architecture world)
Developing “disruptive” prototypes that challenge the current Internet
• E.g. Where should the intelligence in the network reside?
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Trouble with Success (CSTB 2001 Report)
os·si·fi·ca·tion := The process of becoming set in a rigidly conventional pattern, as of behavior, habits, or beliefs (American Heritage Dictionary)Intellectual ossification– E.g., it’s not TCP!
Infrastructure ossification– What researchers want may not be deployed in a
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Denial of Service (DoS) Attacks
Network functionality allowed the possibility for DoS attack– First “wave”: Web-server oriented– Next “wave”: network impact (e.g. code-red virus)
Follow-up Research– TCP ‘accept queue’, OS implementation etc– Source-oriented (‘stop close to the source’)– Router-level research: IPprefix lookup – …
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IP Network Traffic Engineering issues for large providers
OSPF/IS-IS: dynamic routing protocolProblem: determine link weights in OSPF/IS-IS networks to load balance a networkEarly-exit/Late-exit routing issues
Router Buffer sizing:– Bandwidth-delay product
• Consider 40 Gbps link and 250 ms round-trip delay
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Routing Table Growth
CIDRIP address lookup algorithms– Need to stay with line rate (approaching
40Gbps)Packet Filtering and classification
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Router Architecture evolution
General purpose computer architectureDifferent architectures for different “purposes”– Shared CPU architectures– Shared forwarding engine architectures– Shared nothing architectures– Clustered architectures
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Router Architectures …
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Needs/Issues in Networking Research
Recap:– Current networks-related research– Future networks/services-related research– External factor that drives research (often
for current networks; however, principles might be useful for “future” networks)
Issues:– To highlight a few examples
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Broadband Access Technology and Service Dynamics
Broadband access Technology (DSL, Cable Modem) designed for “web”model– Lot of download bandwidth– Not much upstream bandwidth
Challenge faced (last few years)– P2P services: Napster, …– VoIP services
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Broadband Access Technology and Service Dynamics (cont’d)
Can we design an access mechanism that is dynamically adjustable between upstream and downstream– Time-Division Duplexing (TDD)? Others?– Require solid knowledge of physical, data link, and
transport layer?Questions:– How well will the dynamics work?– How does it impact service behavior? Where is the trade-
off?– Are there possible pitfalls due to dynamism? And How to
handle them?• (recall: lesson learned from Telephone dynamic routing, TCP
congestion, …)
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If IP layer link setting is dynamically adjustable to address for failureIf optical networking handles its own dynamic routing (GMPLS)– Good for each network, may not be good
together?• Can the inter-related network go into tailspin?
– How does ‘DoS’ attack based ‘increase’ in network traffic impact dynamic adjustability?
– How do we know good from bad traffic (e.g., a new P2P product popularity, or a new DoSattack)?
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Routing table growth
Data source: http://bgp.potaroo.net/
Our recent estimate:N = 105625 + 920.608 (4 Y - 8007)1.52894, for Y >=2002
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Routing table growth: problemsInternet Architecture Board: Routing and addressing workshop (reported at IETF67, San Diego, CA, Nov’06)– TCAM/SRAM for routers slow growth– ASIC is already pushing limits– Memory speed improves about 10% per year– State growth is “super-linear”– Current trends in the growth are not scalable– Use of IP addresses for both ID and Location is a
problem– Sort of “second CIDR wave”, but more difficult
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Future Directions:
Developing “disruptive” prototypes that challenge the current InternetHow to do it?Not possible to test over the current Internet– It’s a production network!
Retro-fitting is difficult (remains “patch-work” problem)
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Steps to Making it happen ..NSF’s new research program: – FIND (Future Internet Design)– Inviting proposals on radical architectural directions
GENI (Global Environment for Networking Innovations) http://www.geni.net– A large-scale proposed test-bed for experimentation
• Experimentation in every layer of the network• Customized hardware development• Test before deploy time environment• Allow many researchers to participate• Alliance with European Community
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