Aadil Zia Khan and Shahab Baqai

LUMS School of Science and Engineering

QoS Aware Path Selectionin Content Centric Networks Fahad R. Dogar

Carnegie Mellon University

2012 IEEE International Conference on Communications (ICC)

Presenter: 101062522 劉泓緯

Outline• Introduction• Problem Description• Algorithm• Ant Colony Routed Networks for Delay Sensitive Traffic• Routing for Bandwidth Intensive Traffic

• Analysis and Evaluation• Conclusion

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Introduction• Internet has become a medium for massive content distribution with end host identification based protocols• Information sharing should be based on the content name, independent of the hosts’ identity where it is available

• Application layer approach exists some inherent issues• Peer-to-peer approach requires network probing and knowledge regarding the topology• Multicast may work but fail at scalability

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Introduction (Cont.)• Content Centric Network• Network level caching• Security• Intelligent forwarding

• Modification for forwarding technique• Real time multimedia traffic• Bandwidth intensive but delay tolerant traffic

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Problem Description• How to select the best next hop from many possible next hops at each CCN router such that:• The per packet delay of real time traffic is minimized• Download time of high bandwidth delay tolerant traffic is minimized

• Sample Scenario1

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• Analogy to ant colony

Ant Colony Routed Networks

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• Packet Type• Interest Packet• Data Packet

• Forwarding Path (Interest Packet Received)• Pheromone values should be stored• The interest packet is forwarded to the next hop having the greatest pheromone value in the FIB Scaling

factor

Pheromone value

The probability to forward to other

faces

Delay Sensitive Traffic

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• Return Path (Data Packet Received)• When a data packet is first received, the pheromone entry is:

• For subsequent duplicate data packets, the pheromone value is:

0.1

0.5

Delay Sensitive Traffic (Cont.)

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Delay Sensitive Traffic (Cont.)

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Routing for Bandwidth Intensive Traffic• Measurement of all possible paths to the content

• Info-interest packet• End host would send out Info-interest packet for the required content

• Info-data packet• Contains bottleneck bandwidth

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Routing for Bandwidth Intensive Traffic (Cont.)• When a CCN node receives Info-interest packet• Check Content Store• If it exists, measure the available bandwidth on that face and reply the information in the Info-data packet• If not, forward on all faces

• When a CCN node receives Info-data packet• Read available bandwidth from the packet to FIB• Compare bandwidth for specific content on all faces 10 /

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Analysis and Evaluation• Environment Setup• Mesh topology in Emulab, consisting of • 20 routers• 3 content sources• 1 content subscriber

• Parameters• Link delays are uniformly distributed between 30 and 60 milliseconds• Packet size was 1Kb and streaming rate was 250 packets per second

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• Delay Sensitive Traffic• Convergence time, Duplicate packets, Average packet delay

Analysis and Evaluation (Cont.)

Convergence Time

Duplicate Packets

Average Packet Delay

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• Bandwidth Intensive Traffic• Achieved bandwidth

Analysis and Evaluation (Cont.)

Combine highest and lowest bandwidth

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Conclusion• Propose modifications to the CCN framework for:• QoS based path selection• Multisource content retrievaland get much better results compared with random forwarding

• Future work• How this framework would work for other QoS metrics

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