Networkmodel

 

	OSI 7 Layer		equipment	header	address	protocol	PDU	TCP/IP 4 Layer
upper	7	application		UI(User Interface)		ftp-data : 20, ftp : 21 ssh : 22 telnet : 23 smtp : 25 dns : 53 boots(dhcp) : 67, bootcp(dhcp) : 68 tftp : 69 http : 80 pop3 : 110 imap4 : 143 snmp : 161, snmp-trap : 162 https(SSL) : 443	message	application
	6	presentation		encode/decode encrypt/decrypt compress/deconpress
	5	session		session(logical connection control)
lower	4	transport	L4 Switch	service to service connection-oriented vs connectionless favor reliability vs favor efficiency flow control, congestion control	port address	tcp udp	segment	transport
	3	network	Router	end to end, routing(목적지) : best path 비연결성, 비신뢰성 --> ICMP가 보완	ip address	icmp IP	packet	internet
	2	data link	L2 Switch Switching hub Bridge	node to node(hop to hop), error detection(FCS)	MAC address	artp LAN : ethernet WAN : PPP, HDLC, frame-relay	frame	network interface
	1	physical	cable connector repeator hub	electric signal transporting bits			bit stream	(hardware)

upper - 데이터 생성
lower - 데이터 전달
OSI 7 Layer - Open System Interconnection
equipment - dst ip address, routing table을 이용한 packet switching
Router
- NIC: NetworkInterfaceCard Switcing
-flooding, learning, filtering && forwarding, aging
equipment
3 - dst ip address, routing table을 이용한 packet switching
2 - NIC: NetworkInterfaceCard Switcing
            -flooding, learning, filtering && forwarding, aging
1 - hub : multiport repeater flooding
header
6 - encoding : ascii ~~~~
5 - distinguished user sessions
4 - distinguish data streams
favor reliability
favor efficiency
connection oriented
flow control : receiver 의 buffer size 에 맞게 TCP Window size 조절
congestion control : 송신자가 패킷의 전송량을 조절
2 - 오류없이 한 장치에서 다른 장치로 프레임 전달 노드간
물리적 연결 정의 노드간 에러없이 프레임 전송 책임
address
4 - 어플리케이션 구분을 위한 포트주소
3 - 최종 목적지 지정을 위한 논리적 주소
2 - Media Access Contorl 물리적 주소 48bit 
protocol
- header의 구조 정의
3 - protocol
ICMP 0x1
TCP 0x6
UDP 0X11(17)
pdu
- protocol data unit header + payload + footer (L2) SDU=payload
SDU=payload
1 - PDU 로는 X
TCP/IP 4 Layer
2 - Network Access 라고도 함