Internet Audio/Video Streaming stored audio/video refers to on-demand requests for compressed audio/video files youtube, netflix 저장, 압축된 영상매체를 불러오기 Streaming live audio/video refers to the broadcasting of radio and TV programs through the Internet 뉴스, live 방송 Interactive audio/video refers to the use of the Internet for interactive audio/video applications 카카오 보이스톡, 페이스톡, 줌 각 서비스 마다 요구사항이 달라서 나누..

Position of Transport-Layer Protocols UDP is an unreliable connectionless transport-layer protocol 그때그때 -> unreliable TCP is a reliable connection-oriented transport-layer protocol 보내기 전에 connection establishment -> connection teardown SCTP is a new protocol that combines the features of UDP and TCP end-to-end의 data delivery User Datagram Protocol (UDP) The User Datagram Protocol (UDP) is a conn..

Logical Connection at the Transport Layer Located between the application layer and the network layer. Provides a process-to-process communication between two application layers transport layer는 layer 1,2,3 와는 달리 통신망 상에 존재하는 것이 아니라 end system(host computer)에만 존재한다. Process-to-Process Communications Network layer versus. transport layer Network layer: host-to-host(집에서 집) computer level Transport ..

IPv6 Addressing The main reason for migration from IPv4 to IPv6 is the small size of the address space in IPv4 An IPv6 address is 128 bits or 16 bytes (octets) long, four times the address length in IPv4 232 -> 2128 IPv6: Address Space The address space of IPv6 contains 2128 addresses. This address space is 296 times the IPv4 address—definitely no address depletion—as shown, the size of the spac..

21.1 Introduction Unicasting One source and one destination network. One-to-one relationship Each router in the path of the datagram tries to forward the packet to one and only one of its interfaces. Unicasting (one-to-one), Multicasting(one-to-many), Broadcasting (one-to-all) Multicasting One source and a group of destinations. One to many relationship Source address is a unicast address, but t..

routing에서 forwarding table을 통해 forwarding이 어떤 방식(protocol)에 의해서 이루어지는가? An Internet as a Graph To find the best route, an internet can be modeled as a graph 경로의 edge의 cost를 모두 더했을 때 가장 적은 cost가 드는 길(path)을 찾는 과정 -> routing 방법 What is cost? distance 몇 차선 도로 요금 등등... 으로 생각 Least-Cost Trees 가장 cost가 적게 드는 tree 7개의 노드 * 각 노드에서 다른 모든 노드로 가는 경로 6개 N(N-1) 개의 path를 찾는다. Root node가 Routing Algorithms Sev..

19.1 Internet Protocol (IP) Position of IP and other network-layer protocols in TCP/IP protocol suite Three auxiliary protocols: ICMP, IGMP, ARP IP를 지원하기 위한 보조적인 프로토콜 - IGMP(one-to-many), ICMP(error control), ARP Datagram Format(매우 중요) 인터넷은 packet switching 방식에 근간을 두고 있음. virtual circuit과 datagram 중 datagram을 사용하고 그렇기 때문에 packet 하나가 datagram 단위이다. header는 최소 20바이트에서 최대 60바이트까지 될 수 있다. 뒤의 option ..

Communication at Network Layer 주소를 설정하고 경로를 설정하는 것이 핵심 기능 (addressing, routing) 18.1 Network Layer Services Packetizing (transport layer로 부터 오는 정보를)Encapsulating and decapsulating(data-link layer로부터 오는 packet을) the payload Routing and Forwarding Routing is applying strategies and running some protocols to create the decision-making tables for each router (경로 배정, decision making) Forwarding as th..