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Content centric networks


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Future Internet Architecture: Content Centric Networks

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Content centric networks

  2. 2. Papers 1. Jacobson, V et al (2009). Networking Named Content 2. Grassi, G et al (2014). VANET via Named Data Networking
  5. 5. Background ● Traditional TCP/IP Architecture ○ Built to solve resource sharing issues ● Use of IP address ○ IP packets contain two identifiers ■ IP address for the source ■ IP address for the destination
  6. 6. Issues ● People value the internet for WHAT content it contains HOWEVER ● Communication is still in terms of WHERE Source:Cisco VNI: Forecast and Methodology, 2015–2020
  7. 7. Current Challenges ● Availability ● Security ● Location-dependence
  9. 9. Introduction ● Content-Centric Networking (CCN) : networking paradigm centered around content distribution rather than host-to-host connectivity. ● This change from host-centric to content-centric has several attractive advantages, such as: ● network load reduction ● low dissemination latency, and ● energy efficiency.
  10. 10. Benefits of CCN ● Content caching: reduce congestion and improve delivery speed, ● Simplicity: in configuration of network devices, and ● Security : building security into the network at the data level. Source:
  11. 11. CCN Concept TCP/IP CCN Protocol Stack
  12. 12. CCN Protocol Stack ● Strategy Layer: ○ Dynamic optimization choices required to best exploit multiple connectivities under changing conditions ● Security Layer: ○ CCN secures the content itself ○ Avoids host based vulnerabilities
  13. 13. Similarities & Differences between CCN & IP Similarities Differences • Both architectures share the same hourglass shape, with the IP/NDN layer as the narrow waist. • Both send datagrams. • Both follow end-to-end principle. • Both use their own namespace for data delivery (i.e. IP uses IP addresses to deliver datagrams between IP nodes; NDN uses the application name space to deliver datagrams between NDN nodes) • CCN secures the content while IP secures the connections • They use a different namespace: IP address v.s. Name. • NDN includes a security primitive directly at the narrow waist (every Data packet is signed). • IP sends packets to destination addresses; NDN uses Interest packets to fetch Data packets. • IP (by definition) has a stateless data plane. NDN has a stateful data plane. Together with the forwarding strategy, this stateful data plane offers NDN networks a variety of desired functions
  14. 14. CCN NODE MODEL
  15. 15. CCN NODE MODEL BROADCAST INTEREST OVER AVAILABLE CONNECTIONS RESPONSE Packet Types: ● Interest ● Packet ● CCN communication is consumer driven
  16. 16. CCN NODE MODEL ● Broadcasting through various interfaces ● Data is transmitted only in response to an Interest and consumes that Interest ● Data satisfies an Interest if ContentName in the Interest is a prefix of that in the Data ● When a packet arrives on a face a longest-match lookup is made ● Allows dynamic content generation through the use of active names
  17. 17. BASIC OPERATION OF CCN 1. A packet arrives on a face [interface] 2. Longest-match look-up is performed on its name 3. An action performed based on the result of the lookup
  18. 18. CCN FORWARDING ENGINE MODEL 1. FIB: a. forwards interest packets towards potential sources of matching data b. Allows multiple sources for data c. Multiple output faces 2. Content Store: a. caching functionality; b. each packet can be used by other consumers 3. PIT a. Keeps track of Interests forwarded upstream towards content sources
  19. 19. TRANSPORT
  20. 20. TRANSPORT ● Operates on top of unreliable packet delivery services ● Loss/ damage of data in transit ○ Mobility ○ Ubiquitous computing ● Provision of reliable & resilient delivery ○ Senders are stateless ○ Consumer retransmits unsatisfied Interest ● Reliability & flow control ○ Flow balance: Retrieval of one packet per Interest ○ CCN flow balance maintained at each hop unlike TCP ○ Use of LRU memory ( cache)
  21. 21. TRANSPORT ● Sequencing ○ Uses a hierarchical naming structure ○ Names are made of various components ● Rich connectivity, mobility & strategy ○ Takes advantages of multiple interfaces on machines ○ Rapidly changing connectivity ○ Multiple connectivity through per FIB- entry face list ● Simultaneous connectivity
  22. 22. ROUTING
  23. 23. ROUTING ● Works with existing routing protocols ○ Intra domain routing [IS-IS & OSPF] ○ Inter-domain routing ● Automates routing infrastructure protection
  24. 24. SECURITY
  25. 25. CONTENT BASED SECURITY ● Protection and trust level embedded within the content rather than connections in IP networking ● Authentication of content with digital signatures ○ content, routing, policy information ● Private content is encrypted ● Provides end to end security between content publisher and content consumer ○ No one size fits all for trust model ● CCN security model: SDSI/SPKI ○ Model keys are mapped to identities via controlled namespaces ● Implementation of Policy Based Routing
  26. 26. EVALUATION
  27. 27. EVALUATION BULK TRANSFER PERFORMANCE DATA TRANSFER EFFICIENCY ● CCN performance comparable to TCP ● However it is lower due to its larger header overhead ● TCP throughput: 90% ● CCN throughput: 68%
  28. 28. EVALUATION CONTENT DISTRIBUTION EFFICIENCY ● To measure sharing performance ○ Compare the total time taken to simultaneously retrieve multiple copies of a large data file (6MB) over a network bottleneck using TCP and CCN. ● With a single sink, TCP's better header efficiency allows it to complete faster than CCN. ● But as the number of sinks increases, TCP's completion time increases linearly while the CCN performance stays constant.
  29. 29. CONCLUSION ● Content is the focus as opposed to host to host connectivity ● CCN follows IP design principles but uses named content ● Simple and scalable architecture ● Enhanced security, delivery efficiency & fault tolerance ● CCN is useful for both content distribution & point to point protocols
  32. 32. INTRODUCTION ● Wide range of wireless interfaces available in modern cars ● Cars should be able to choose the best available interface or use multiple in parallel Power Line Communication
  33. 33. ISSUE ● Cars mostly connected to the internet via Cellular Networks only ● Two ways of connecting vehicles: ○ Vehicle to Infrastructure communication (V2I) ○ Vehicle to Vehicle Communication (V2V) ■ Usage is limited to one hop communication for collision prevention only ● Limitation of TCP/IP in enabling the use of various applications for V2V communication
  34. 34. PROPOSED SOLUTION ● Use of Named Data Networking (NDN) to address VANET challenges ● Benefits of naming data: ○ Decouples communication from specific interfaces and endpoints ○ Enable vehicles to use any available interfaces and fetch data from any other node when there is physical connectivity ● In this paper a prototype of Vehicular NDN (V-NDN) was designed and implemented
  36. 36. NDN ● NDN Data Structures: ○ Content Store (CS) ○ Pending Interest Table (PIT) ○ Forwarding Information Base (FIB)
  38. 38. V-NDN ● Great enabler for vehicle networking, HOWEVER, ● Modifications to NDN operations are required for VANET environment ○ PIT: should be able to cache all received data regardless of whether it has a matching PIT entry or whether it needs data for itself ○ Caching strategy enables rapid dissemination of data in highly dynamic environments ○ The data can be carried by the car even if there is no connectivity
  39. 39. IMPLEMENTATION ● NDN Daemon: ○ core capabilities through maintaining data structures ○ Name prefix matching ○ Packet forwarding ● NDN Local Faces ○ Support application registration, Interest request by consumers and content delivery. ○ Use of IEEE 802.11 in ad hoc mode for V2V & provide interface with LAL to support Wi-Fi broadcast ● NDN Network Faces: ○ Provides adaptation functionality based on technology used ● Link Adaptation Layer ○ Layer 2.5, takes advantage of layer 2 mechanisms ● Location Service
  40. 40. ENHANCING WI-FI BROADCAST FOR V2V ● L2 WiFi broadcast used for all the V2V communications: ● Challenge with IEEE 802.11 ○ No collision prevention/ detection/recovery mechanism for broadcast transmission ● Solution: Wi-Fi broadcast support for VANET ○ Packet forwarding algorithm ■ Assumption: each vehicle is equipped with GPS and Digital Map ■ Forwarding strategy by spreading NDN Interest packets in all direction implemented in Link Adaptation Layer
  41. 41. ENHANCING WI-FI BROADCAST FOR V2V ● LAL uses: ○ Forwarding timer ○ Computation of timer 1 D(sender,receiver) where D distance computed using the location service; and a small random component used to randomize the transmission line timer=
  43. 43. EXPERIMENTS ● 10 cars ● Two applications over NDN: ○ Info-traffic: ■ emulates traffic request for a specific location ■ Area encoded in the Interest carried in Interest Packets ■ Name intersections and streets stemming used instead of numbers ■ i.e./traffic/westwood-at-strathmore/ ■ Car from this location can effectively respond to the Interest ○ Road Photo: ■ Represents photo requests from a location ■ Any vehicle that has been to this location can respond
  44. 44. EXPERIMENTS ● Vehicular Application Domains ○ V2V ○ I2V (fig 2(b) ○ V2I (fig 2 (c) - 2 (a)) ○ Network disruption due to rapidly changing topology and short link duration ○ In-network storage: caching
  45. 45. EXPERIMENTS ● Still, platooning, moving around campus ● Fig. 4(a) shows the CDF for the number of retransmissions for the InfoTraffic application in all the 3 types of mobility. ● static case: 75% of the packets need no more than one retransmission. ● Mobility: this number goes down to about 65%, however the type of mobility (either on the P8 roof or on the roads) has a negligible impact on the number of retransmissions. ● 95% of the packets are acknowledged within 5 retransmissions or less (the max-retransmission was set to 7),
  46. 46. EXPERIMENTS: CACHING ANALYSIS CACHE/FORWARD STATISTICS ● For consumers & mules ● Caching is more effective during mobility ● Limited mobility ● Mules observation: 66% of the Interests were found using the local cache
  47. 47. NDN Operation in multihomed environment ● Two cars (consumer, producer) ● We ran the Road-Photo application: the consumer requested a photo to be taken by the producer. Interest and Data packets were transmitted via all available interfaces. ● Photos were taken in real-time upon receiving an Interest, their sizes were between 68KB and 100KB. Each photo was split into several Data packets of 1300 bytes each. ● Fig. 5 shows on which interfaces the consumer received a chunk of content. The consumer was able to seamlessly receive consecutive chunks of the same picture from different interfaces via different communication channels.
  49. 49. V-NDN AT SCALE ● Fig 6a & 6c shows that when the # of cars interested in the same information increases , system performance improves substantially as measured by the satisfaction time & overhead matrix ○ caching and data mules ○ Faster response ● Fig 6b: 35% of Interests are already acknowledged even before being transmitted once ○ caching
  50. 50. CONCLUSION
  51. 51. DISCUSSIONS ● V-NDN removes the isolation between applications and network transport, allowing forwarding nodes to handle data based on application needs. ● The communication can start spontaneously due to caching ● Furthermore, locally produced data and data with local meaning, such as traffic information, no longer need to be transferred to remote servers before being available to neighbor nodes; ● Data that is produced and consumed in loco can remain in loco and be delivered to the consumers along the shortest physical path.
  52. 52. CHALLENGES
  53. 53. Challenges & Future Work ● Study of a V-NDN forwarding strategy to make the best use out of node multihoming. ● Data naming: shows that encoding geolocation into names can help direct Interest forwarding for applications using location-based data; however other types of applications, e.g. fetching today’s news, are unable to make use of geolocation. ● security and privacy concerns
  55. 55. ● For scalability purpose, broadcasting in a huge network (e.g. the Internet) is not a good approach. How can CCN handle this problems? Any mechanism similar to DNS or Content Broker that could be used in CCN? [Pham, Nhat] ● Content naming issues in CCN [Pham, Nhat] [Taesik Gong] [Sungjoon Park] ○ Same name for data ○ Same data but different name ● Ease of updating Naming and routing. Use of SDN for NDN? [Hyunwoo Choi] ● Caching data packets & interest packets on CCN & its impact on the E2E principle [Shah] ● Co-existence of CCN with IP networks [Sungjoon Park] CCN: DESIGN & PERFORMANCE
  56. 56. ● Could the breadcrumbs systems cause mobility problems? [Eric] ● Is CCN scalable like IPv6 [ Romain Olivier] CCN: MOBILITY & SCALABILITY
  57. 57. 1. CCN uses content-based security ( digital signatures and encryption) but it still is vulnerable to DoS attacks. [Hailu Belay] [ Romain Olivier] ○ Hiding legitimate content ○ Flooding Interest packets 2. Drawbacks of using Digital signatures? Any other ways of enforcing security? [ Romain Olivier] 3. Fake tags on the network [Soowon Kang] CCN: SECURITY
  58. 58. ● Stakeholders willingness to adopt CCN [Hailu Belay] ● Modification of existing systems e.g. search engines for CCN [ Romain Olivier] CCN: ADOPTION & COMMERCIALIZATION
  59. 59. ● Caching content in NDN and propagating stale information [Romain Olivier] ● How to avoid redundant content in the network [Romain Olivier] ● How does V-NDN used forwarding when hosts have multihoming [Shah] ● Normalization problem for content naming [Wonseok] V-NDN: DESIGN & PERFORMANCE
  60. 60. ● Privacy and trust [Hailu Belay] ● Development and integration of high performance cryptographic algorithms [Hailu Belay] ● Security not addressed [several students] V-NDN: SECURITY
  61. 61. ● Killer application[Hailu Belay] ● Data Retention policy and content regulation [Hailu Belay] ● Willingness to cooperate and share content between vehicles [Hyunwoo Choi] V-NDN: ADOPTION & COMMERCIALIZATION
  62. 62. References 1. Jacobson, V. .et al (2009). Networking Named Content 2. Grassi, G (2014). VANET via Named Data Networking 3. 4.
  63. 63. ROUTING Figure 2 shows a basic routing scheme in CCN. 1. The client 1 requests content to CCN router H. When CCN router H receives client 1’s interest packet, it checks its content cache table to find whether the requested content is in the table or not. If requested content is found within the cache table, CCN router H sends the requested content to client 1. However if the content is not in the cache table, CCN Router H sends an interest packet to other CCN routers. In this way, each interest packet is sent to the CCN Router A which has the requested content. 2. CCN router A receives an interest packet from CCN router B and checks its cache table. Then CCN router A sends the requested content using reverse path to router H and when each CCN router receives the contents, it stores the contents into content cache. Finally, client 1 receives the requested content from CCN router H. 3. The client 2 requests same content which is requested by client 1. CCN router I receives an interest packet. However CCN router I doesn’t have the requested content in its cache table. In this case, client 2’s request message is sent to node D. 4. When node D receives the interest packet, it sends a data packet including requested content to client 2.