1 lecture 2 – networking paradigms university of nevada – reno computer science &...
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Lecture 2 – Networking Paradigms
University of Nevada – RenoComputer Science & Engineering Department
Fall 2015
CS 791 Special Topics:Network Architectures and Economics
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Outline
Tussle Granularity
Contract-Switching
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Tussle Granularity Tussle:
“a physical contest or struggle”, www.m-w.com
Effects everything else designed on it
A way of expressing “value”
Does it have to be “physical”?
How about economic tussle in the net?
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Tussle Granularity Spatial
Where on the network is involved in the tussle? Where are the entities tussling with each other? How “large” is the unit of tussle?
Paradigm Between Where
Unit
Circuit-Switching
End-to-End Circuits
Packet-Switching
Hop-to-Hop Datagrams/Packets
Paradigm
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Tussle Granularity Temporal
How frequent does the tussle take place? How “long” is the unit of tussle?
Paradigm Frequency Unit
Circuit-Switching
Per flow/session
Minutes
Packet-Switching
Per packet Milliseconds
Are these two paradigmatic tussle granularities enough to handle current
challenges in the Internet?
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Tussle Granularity: Value Economic granularity?
How flexible is it to express your Willingness-to-pay Value of the data/bit
Current: only at the access level all application traffic is treated the same (except VoIP,
which requires extra payments)
Paradigm
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Tussle Granularity: Trust Security granularity?
How flexible is it to express your sense of Security of the data Privacy of your ID
Always tradeoffs Too private: cannot track criminals (e.g. anonymizers) No privacy: 911 calls possible
Paradigm
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Tussle Granularity: Trust Are you comfortable with sending your financial
information over WiFi links? Do you “trust” the network? Or do you just no trust the WiFi link? Can you express this to the network provider?
Trust levels: Can we quantify?
If not quantifiable, can it be part of the paradigm or even architecture?
Paradigm
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Implied Challenges
Tussle Granularity: Edge-to-Edge
Some of the current architectural problems: Users cannot express
value choices at sufficient granularity – only at access level
Providers do not have economic knobs to manage risks involved in
• investing innovative QoS technologies and
• business relationships with other providers
flexibility in time:forward/option pricing
flexibility in space:user-defined inter-domain
routes
capability to provide e2e higher quality services
money-back guarantees, risk/cost sharing
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Inter-domain struggles…
When crossing domains, all bets are off..
End-to-end reliability or performance-criticality requires assurance of single-domain performance, i.e., “contract”s efficient concatenation of single-domain contracts
Inter-domain routing needs to be aware of economic semantics contract routing + risk management
How to address translation of these struggles to architectural problems?
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Contract-switching: A paradigm shift…
Circuit-switching
Packet-switching
Contract-switching
ISPA
ISPC
ISPB
e2e circuits
ISPA
ISPC
ISPB routable
datagrams
ISPA
ISPC
ISPB contracts
overlaid on routable datagrams
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A Contract-Switched Network Core
Contracts: a practical way to manage “value flows”
Technologies to Support QoS
Economic considerations for service definition and delivery Scalability, Efficiency
and Fairness Contract timescales Cost recovery Pricing the risk in QoS
guarantees Single-domain and
end-to-end contracts
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Basic Building Block: Intra-domain dynamic contracts
Contract components performance component, e.g.,
capacity financial component, e.g., price time component, e.g., term
Network Coreaccessed onlyby contracts
Cu
stom
ers
EdgeRouter
EdgeRouter
EdgeRouter
EdgeRouter
EdgeRouter
EdgeRouter
Stations of the provider computing
and advertising local prices for edge-to-
edge contracts.
Stations of the provider computing
and advertising local prices for edge-to-
edge contracts.
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Contract Link
An ISP is abstracted as a set of “contract links”
Contract link: an advertisable contract between peering/edge
points i and j of an ISP with flexibility of advertising
different prices for edge-to-edge (g2g) intra-domain paths
capability of managing value flows at a finer
granularity than point-to-anywhere deals
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Can we achieve e2e QoS? Contract Routing:
Compose e2e inter-domain “contract paths” over available contract links satisfying the QoS requirements
Calculate the contract paths by shortest-path algos with metrics customized w.r.t. contract QoS metrics
Two ways: link-state contract routing at macro time-scales path-vector contract routing at micro time-scales
Monitor and verify that each ISP involved in an e2e contract path is doing the job
Punish the ISPs not doing their job, e.g. as a money-back guarantee to the others involved in the e2e contract path
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Link-State Contract Routing: Macro-level, proactive
User X
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3
5
ISPA
ISPC
ISPB
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OwnerISP
Link
QoS Term
OfferedAfter
Price($/term)
A 1-2 10Mb/s 2hrs 1hr $10
A 1-3 40Mb/s 5hrs 15mins $80
B 2-4 100Mb/s
3hrs 2hrs $110
C 3-5 20Mb/s 1hr 30mins $8
C 4-5 60Mb/s 1day 2hrs $250
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Most cost-efficient route
Max QoS route
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Path-Vector Contract Routing: Micro-level, on-demand, reactive
Provider initiates… ISP C wants to
advertise availability of a short-term contract link
User X
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3
5
ISPA
ISPC
ISPB
1 4
[C, 5-4, 30Mb/s,
45mins, $9]
[C-B, 5-4-2, 20Mb/s, 45mins, $6+$5]
[C-B-A, 5-4-2-1, 20Mb/s, 30mins, $7.3+$3]
[C, 5-3, 10Mb/s, 30mins, $5]
[C-A, 5-3-1, 5Mb/s, 15mins, $1.25+$1.2]
pathannouncement
path
announcement pathannouncement
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Path-Vector Contract Routing: Micro-level, on-demand, reactive
User initiates… User X wants to know if it can
reach 5 with 10-30Mb/s for 15-45mins in a $10 budget
User X
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3
5
ISP A
ISPC
ISPB
1 4
[5, A-B, 1-2-4, 15-20Mb/s, 20-30mins, $4]
[5, A, 1-2, 15-30Mb/s, 15-30mins, $8]
[5, 10-30Mb/s, 15-45mins, $10]
[5, A, 1-3, 5-10Mb/s, 15-20mins, $7]
Paths to 5 are found and ISP C sends replies to the user with
two specific contract-path-vectors.
path requestpath request
path request
[A-B-C, 1-2-4-5, 20Mb/s, 30mins]
[A-C, 1-3-5, 10Mb/s, 15mins]
Paths to 5 are found and ISP C sends
replies to the user with two specific contract-
path-vectors.
replyreply
reply
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Deployment Issues
How to motivate ISPs to participate? ISPs are very protective of their contracting
terms – due to competition.• But, BGP has similar risks too..• Observation of opportunity costs
PVCR can be done at will..• Not much to loose if ISPs participate with their
leftover bandwidth.
Monitoring and verification of contracts Who is breaking the e2e performance? Active measurements can be OK for LSCR,
but PVCR needs lightweight techniques.
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Contract-Switching: A generalization
A generalization of packet-switching A packet is a little contract with a very short duration?
Paradigm Between Where
Unit
Circuit-Switching End-to-End Circuits
Packet-Switching Hop-to-Hop Datagrams/Packets
Contract-Switching
Edge-to-Edge Contracts
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Lecture 2: Summary Tussle Granularity
Temporal Spatial Economic
Contract-Switching Edge-to-edge Contract as a unit of tussle Potential to offer end-to-end QoS services Value and risk management at fine-enough granularity
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Lecture 2: Reading Clark, Wrocklawski, Sollins, and Braden, Tussle in
Cyberspace: Defining Tomorrow's Internet, IEEE/ACM Transactions on Networking, 2005.
Yuksel, Gupta, and Kalyanaraman, Contract-Switching Paradigm for Internet Value Flows and Risk Management, IEEE Global Internet Symposium, 2008. (also in Ramamurthy, Rouskas, and Sivalingam, Chapter 7)