1. Multimedia and Mobile communications Laboratory CCN 1 DK Han dkhan@mmlab.snu.ac.kr Junghwan Song jhsong@mmlab.snu.ac.kr 2012-3-7 Computer Networks Practice

2. Introduction Aim of old days (‘60s-‘70s) network  Resource(card readers, tape drives) sharing  Host-to-host model  Conversation between exactly two machines Now  People value the Internet for what content it contains, but communication architecture is still focused on host-to-host  ‘what’ is more important than ‘where’ 2/22

3. Need for new networks Storage cost is getting cheaper sharply  Compared to networking cost IP datagram can only point endpoints Users/applications care “ WHAT TO RECEIVE ”  They don’t care “ FROM WHERE or FROM WHOM ”  So, host-based comm. model is outdated 3/22 Contents Centric Network is proposed

4. CCN(Content-Centric Networking) Communication architecture built on named data Packet ‘address’ names content, not location  Users are interested in what content, not where it is 4/22

5. IP networking vs. content networking Network prefix Content name 5/22

6. CCN protocol stacks Content chuncks  Data are fragmented into chunks Strategy layer  Best exploit multiple connectivity under changing condition Security layer  Secure content itself, avoiding host-based vulnerabilities 6/22

7. How CCN works? Client requests a content  Without specifying ‘from where’ Nodes provides the content or forward requests to find one Nodes on the path caches contents  So that future demands can be served A A B B C C D D E E G G F F H H I I J J K K Client 1 Client 2 Client 3 A A B B D D H H G G 7/22

8. CCN packet types Two types of CCN packets  Interest packets  Data packets 8/22

9. Node components Content Store (buffer memory)  Caches Data packets Pending Interest Table (PIT)  Keeps track of Interest forwarded upstream (bread scrumbs) Forwarding Information Base (FIB)  Forwarding table  Allows a list of outgoing interfaces 9/22

10. Basic operation Data simply follows the chain of PIT entries back to demander 10/22

11. Basic operation - Example 11/22 Interest MMLAB.kr/member/tjchung/ profile/v/s0 MMLAB.kr/member/tjchung/profile/v/s0 /MMLAB.kr DATA:/ MMLAB.kr/member/tjchung/ profile/v/s0 MMLAB.kr/member/tjchung/profile/v/s0 1 0 No Cache!

12. In a nutshell, 12/22

13. Next time, We will see how to build up CCN environment. 13/22