p roactive s elective n eighbor c aching for e nhancing m obility s upport in i nformation -c entric...
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PROACTIVE SELECTIVE NEIGHBOR CACHINGFOR ENHANCING MOBILITY SUPPORT IN INFORMATION-CENTRIC NETWORKS
Xenofon Vasilakos - [email protected]. Student at AUEB,
MMLab member
X. Vasilakos, V.A. Siris, G.C. Polyzos and M. Pomonis,
Reduce delay experienced after handing off to another location
• Mobile Users (MUs) in an ICN architecture• Running applications with strict delay
requirements
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Domain A
Receiver-Driven model in ICN
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Domain B
Publisher
PublisherICN architecture
MU just re-subscribes after completing the handoff
ICN is mobile-ready
• What about delay after handoff?– Resend request, wait for resolution and path formation– Wait to get data from (another?) publisher
• Delay-sensitive applications:– Realtime/emergency notifications, – Teleconferencing, online gaming, etc..
• Sensitive to delay jittering– Multimedia Streaming services
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• Proactive Caching• SNC: Selective Neighbor Caching• Evaluation• Future Work and Conclusion
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Proactive Caching
• Use proxies– Handle requests– Proactively Cache IOs
• Neighboring proxies– One hope ahead
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Proxy: Cache with mobility support mechanisms
Proxy: Cache with mobility support mechanisms
J: Set of neighbors
Publisher
Proactive Caching
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Proxy: Cache with mobility support mechanisms
Proxy: Cache with mobility support mechanisms
J: Set of neighbors
Publisher
• Full caching– Proactively fetching and
caching requests and IOs to all neighbors
• Blind approach– Wastes buffer space– Infeasible to cache all
IOs for all mobiles– Increases delay for other
mobiles
• Proactive Caching• SNC: Selective Neighbor Caching• Evaluation• Future Work and Conclusion
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Selective Neighbor Caching (SNC)
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• SNC selects only an optimal subset of neighbors
• GOAL: Minimize total costsjj
iiS: Subset of
neighbor proxies
Current Proxy:
Mobile User
Selective Neighbor Caching (SNC)
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a) Chit: Delay cost from a selected proxy
jj
iiCurrent Proxy:
Mobile User
Selective Neighbor Caching (SNC)
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a) Chit: Delay cost from a selected proxy
b) Cmiss: Delay cost from a non selected proxy
jj
iiCurrent Proxy:
Mobile User
Selective Neighbor Caching (SNC)
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a) Chit: Delay cost from a selected proxy
b) Cmiss: Delay cost from a non selected proxy
c) Ccache: The cost for allocating buffer space jj
iiCurrent Proxy:
Mobile User
Selective Neighbor Caching (SNC)
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a) Chit: Delay cost for getting IOs from a selected proxy
b) Cmiss: Delay cost in case next proxy was not selected
c) Ccache: The cost for allocating buffer space
d) Pij: The probability for the MU to move from i and attach to j
jj
iiCurrent Proxy:
Mobile User
Pij
What is the optimal subset S* ?
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Discover which minimizes the total cost:
cachemisshithithit CSNCSPCSP )())(1()(
JS
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Each Proxy decides autonomously
• SNC is fully distributed and decentralized
Pre-fetching in neighbor j if and only if:
hitmiss
cacheij CC
Cp
• Proactive Caching• SNC: Selective Neighbor Caching• Evaluation• Future Work and Conclusion
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Simulation Delay gains over Full Caching
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Simulation delay gains over No Caching
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• Proactive Caching• SNC: Selective Neighbor Caching• Evaluation• Future work and Conclusion
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Future work
• Network topology, multiple levels of proxies• Traffic demand, IO size, disconnection period• The influence of in-network caching• Online cache cost evaluation• Consider extensions as discussed in the paper
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Conclusion
• SNC trades-off delay with cache cost– Selects the appropriate subset of proxies which
minimizes cost
• Simulation investigations quantify cost gains
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Enhancing Mobility Support in Information-Centric Networks
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Analytical Investigations
• Assume steady state costs and probabilities• Illustrate the tradeoff: delay Vs. Ccache– how the tradeoff and gains of SNC depend on cost
ratios Cmiss/Chit, Ccache/Chit
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Gain over Full Caching reduces with Cmiss/Chit Gain over No Caching increases with Cmiss/Chit
Full Caching
No Caching
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• Gain over full caching increases with Ccache/Chit• Gain over no caching reduces with Ccache/Chit
Full Caching
No Caching
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Defining buffer costs
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Extensions
• Identify mobiles of the same type (having a similar mobility behavior)– Consider proxy transition probability for each type
• When more than one Musrequest item k– nk is the average number
of requests
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