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Content-Centric Networking (CCN)

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Content-Centric Networking (CCN) and Named Data Networking (NDN) are alternative proposals for modern content driven internet.

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Content-Centric Networking (CCN)

  1. 1. Content-Centric Networking (CCN) CS4482 High Performance Networking Dilum Bandara Dilum.Bandara@uom.lk
  2. 2. Outline  V. Jacobson, D. K. Smetters, J. D. Thornton, M. Plass, N. Briggs, and R. Braynard, “Networking Named Content,” In Proc ACM CoNext ‘09, Dec. 2009.  What?  Why?  How? 2
  3. 3. Motivation  60’s & 70’s  Internet was designed to share resources  2 end points talking to each other  Today  Content is the key  Location is irrelevant  Content name  End point  Use network to reach the end point 3
  4. 4. Motivation (Cont.)  Issue – Traffic aggregation  Scalability  Availability  Security  Location dependent  End is not the true end  Solution is not wrong, problem has changed  CCN/NDN solution  Hierarchy of warehouses  Spatial & temporal locality  Name & secure content  Route using name  Cache contents 4
  5. 5. Incentives  Content providers  Lower traffic  Better security, scalability, performance  Consumers  Better QoS, QoE  Free local access  Edge & Tier 2/3 ISPs  Reduce transit traffic  Diminishing return from caching at higher levels  Tier 1 ISPs & routers close to content providers  Starve 5
  6. 6. CCN Applications  Content Delivery Networks (CDN)  Streaming  IPTV, Video on Demand (VoD)  VoIP, teleconferencing  Gathering sensor data & streaming  Controlling actuators  Light control 6
  7. 7. CCN Features  In-network caching  Unicast, multicast, broadcast  Flow control  No routing loops – nonce  Ability to name non-existing data  Enable them to be routed to potential data sources  Security  Mobility  Incremental deployment  Route symmetry  Performance measuring, security  Fine grained control of FIB entries & policies  No need for DNS 7
  8. 8. Architecture  Bits are bits whether they are in routers, wires, or disks 8
  9. 9. Packet Format  Datagram packets  XML-based packets  Receiver driven communication  An interest packet must be send to get a data packet  Clocking, Window of interests, Flow control  Use 1st interest packet to find segment names  CCNx implementation 9
  10. 10. Naming Content 10
  11. 11. Naming Content (Cont.)  Unique names  Binary or human readable  Favor hierarchical names  Large content is segmented  Can invoke remote methods & pass data  /seti.org/resources/update/check_status  /seti.org/resources/update/node102/free_CPU_90  Name unavailable contents  /nws.org/radar9/data_x1_x2_y1_y2/ 11
  12. 12. Node Architecture  All nodes have same architecture  Size of tables & capabilities may vary  Multiple faces  CS – exact match  4KB packets  PIT – exact match  4 sec timeout  FIB – longest prefix match 12 PIT – downstream data path FIB – upstream interest path FIB – Forwarding information base
  13. 13. In-Network Caching  ISPs  Benefit from caching its transit traffic  Can charge content providers to cache  Different policies for content providers  Varying cache sizes – static & dynamic  Content provider can set cache validity  Cache replacement policies  IP routers – MRU replacement  CCN routers – LRU or LFU replacement 13
  14. 14. Routing & Policies  IS-IS or OSPF can be used to fill in FIB  Control plane policies  Prefix forwarding  Multi-path routing  Default route at edge routers  Data plane policies  Policies per FIB entry  Advertise/block specific prefixes  Priorities for faces  e.g., WiFi preferred over 3G  Cache access/sharing 14 Settlement-free peering Consumer-provider relationship
  15. 15. Security  In current Internet we trust the server & not the content  Content authentication – Digital signatures  Content is secured, not its location  Self-signing or hierarchical certificates  Private content can be encrypted  DoS/DDoS  Hard to attack ends  Don’t know where interest packet will be answered  Interest /data flooding is limited to a link  Drop packets without a matching PIT entry  Routers can check whether interests are getting data  Content provider can ask routers to block 15
  16. 16. Issues  Size of CS, PIT, & FIB  CCN name not just a TV but its components  Billions of domains, contents, & chunks  State full routers  Solutions – IP Tunneling, CCN interest tagged with IP  Doesn’t support asynchronous communication  1 message in IP  2/4 CCN messages  Block m-to-1 communication  No TTL  no constrained flooding  Packets are not modified  When should PIT time out?  No clear boundaries  Hard to separate issues in node architecture, naming, & security 16

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