Transcript 슬라이드 1
Computer Networks Practice CCN 1 DK Han Junghwan Song [email protected] [email protected] 2012-3-7 Multimedia and Mobile communications Laboratory 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 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 model is outdated Contents Centric Network is proposed 3/22 CCN(Content-Centric Networking) Communication architecture built on named data Packet ‘address’ names content, not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 IP networking vs. content networking Network prefix Content name 5/22 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 How CCN works? Client requests a content A Without specifying ‘from where’ B Nodes provides the content or forward requests to find one Nodes on the path caches contents D H C E G I F G J K So that future demands can be served Client 1 Client 2 Client 3 7/22 CCN packet types Two types of CCN packets Interest packets Data packets 8/22 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 Basic operation Data simply follows the chain of PIT entries back to demander 10/22 Basic operation - Example No Cache! Interest MMLAB.kr/member/tjchung/ profile/v/s0 MMLAB.kr/member/tjchung/profile/v/s0 DATA:/ MMLAB.kr/member/tjchung/ profile/v/s0 MMLAB.kr/member/tjchung/profile/v/s0 /MMLAB.kr 0 1 11/22 In a nutshell, 12/22 Next time, We will see how to build up CCN environment. 13/22