Networking Named Content

Transcription

1 Networking Named Content Van Jacobson Diana K. Smetters James D. Thorton Machael F. Plass Nicholas H. Briggs Rebecca L. Braynard Presented by: Vladislav Perelman Advanced Networking Seminar Jacobs University Bremen

2 2 Outlook Introduction and Motivation Node Model Transport Routing Security Model Evaluation

3 3 Back in the days... Very few, expensive computers Many people using the same computer Goal of networking protocols share resources Central abstraction host identifier

4 4 Consequences Networking doesn't get along with mobility and intermittent connectivity What vs. Where cognitive mismatch. Mapping requires configuration Lack of security securing the connection doesn't mean the data is good

5 5 Content Centric Networking Where's that server?! What data do I want?

6 6 Coming up Introduction and Motivation Node Model Transport Routing Security Model Evaluation

7 7 CCN Packets Interest Data Data is transmitted only in response to Interest and consumes that Interest

8 8 CCN Names / parc.com/ van/ cal/ 417.vcf/ v3/ s0/ 0x3fdc45a9 7 8: parc.com 3: van 3: cal... 32:3FDC45... Names have to have hierarchical structure. Can be very efficiently hashed (unlike IP addresses) due to explicitness. Can be encrypted or contain arbitrary binary data.

9 9 CCN Forwarding Get /parc.com/videos/ WidgetA.mpg/v3/s2

10 10 CCN Forwarding Data: /parc.com/videos/ WidgetA.mpg/v3/s1...

11 11 Coming up Introduction and Motivation Node Model Transport Routing Security Model Evaluation

12 12 Transport CCN senders are stateless Final consumer has to express Interest in order to get the Data On timeout consumer has to re express that Interest, otherwise the sender will not care to retransmit Given a large amount of Data how do we know what chunk to ask for?

13 13 We need some ordering! TCP uses ACKs to ensure the flow balance and to say which chunk of data was received and which one is still needed (stream oriented transport) CNN makes use of the fact that one can totally order a tree Use relative paths within the tree

14 14 Example Nodes are lexically ordered <next> assumed if not specified otherwise Most recent version: parc.com/van/talks/mit10-08 <rightmost child>

15 15 Example Nodes are lexically ordered <next> assumed if not specified otherwise Most recent version: parc.com/van/talks/mit10-08 <rightmost child> Next available chunk after s1 parc.com/van/talks/mit10-08/v2/s1

16 16 Coming up Introduction and Motivation Node Model Transport Routing Security Model Evaluation

17 17 CCN makes it easier No looping data => don't need stable topology No need for fixed state (approximate state is just fine, false positives don't create a problem) CCN transport model matches that of routing protocols (relies on flooding) Use CCN get infrastructure protection for free since data is secured (coming up in a moment)

18 18 CCN can be used over existing (link state) routing protocols Flood prefix announcements using TLV mechanism If CCN is not supported the announcement is dropped Otherwise nodes use them to build FIBs

19 19 Coming up Introduction and Motivation Node Model Transport Routing Security Model Evaluation

20 20 Content Validation Main idea is to authenticate the binding between the name and the content Each packet in CCN is signed and publicly verifiable Data Receiver Checksum Name

21 21 Trust Model Flexible notion of trust With CCN the key distribution problem goes away SDSI model with locally controlled namespaces

22 22 Coming up Introduction and Motivation Node Model Transport Routing Security Model Evaluation

23 23 TCP vs CCN Round I CCN requires larger pipelining to reach the throughput asymptote Lower transfer rate due to larger header overhead (additional CCN name and SHA 256) Security is provided worth the difference

24 24 TCP vs CCN Round II For TCP the completion time goes up linearly with the number of clients For CCN the completion time stays the same Bandwidth is minimized Latency is minimized

25 25 VoCCN CCN uses Strategy layer to choose best face to send the data to. If link is disconnected CCN switches to a different one No packets lost, <0.1% dropped for arriving too late

26 26 References Future Internet Summer School 2009 (FISS 09) Special Invited Plenary Short Course: (CCN) Content Centric Networking by Van Jacobson, Parc research, USA, Wed bremen.de/ml/index.php?option=com_mlplayer&template=ml2&mlid=1851 A New Way To Look At Networking, by Van Jacobson, #