1984 . ISO OSI (Open System Interconnection).
OSI | ||
HTTP, SMTP, SNMP, RTP, FTP, Telnet, SSH, SCP, SMB, NFS, RTSP, BGP | ||
XDR, ASN.1, AFP, TLS, SSL | ||
ISO 8327 / CCITT X.225, RPC, NetBIOS, ASP | ||
TCP, UDP, SCTP, SPX, ATP, DCCP, GRE | ||
IP, ICMP, IGMP, CLNP, OSPF, RIP, IPX, DDP, ARP, RARP | ||
Ethernet, Token ring, PPP, HDLC, X.25, Frame relay, ISDN, ATM, MPLS, Wi-Fi | ||
, , |
TCP/IP, Internet :
- (FTP, DNS, HTTP, HTTPS, IMAP, IRC, POP3, SMTP, Telnet)
- (TCP, UDP)
- (internet) (IP, ICMP)
- (network access) (Ethernet, X.25, Token Ring, Wi-Fi).
TCP/IP 3 OSI(, ) .
TCP/IP | ||
HTTP, RTP, FTP, DNS | ||
TCP, UDP, SCTP, DCCP | ||
IP ICMP IGMP | ||
Ethernet, SLIP, Token Ring, ATM MPLS | ||
T1, E1 |
TCP/IP IP-. .
TCP/IP . : , , .
IP
IP- 65535 . . IP . IP - 4 . . IP- . IPv4 IP-.
IHL | |||||||||||||||||||||||||||||||
(TTL) | |||||||||||||||||||||||||||||||
IP- (32 ) | |||||||||||||||||||||||||||||||
IP- (32 ) | |||||||||||||||||||||||||||||||
( 320 ) | ( 65535 ) | ||||||||||||||||||||||||||||||
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- 4- , IP. IPv4 4.
- IHL IP- 32- . 5.
- : 0.
- : , IP-, . - 65535 .
- , .
- 3 . , DF (dont fragment) MF (more fragments) , .
- , IP-, IP-.
- , .
- : , IP-. : 1 -ICMP, 6 TCP, 17-UDP.
- : , IP-. IP- .
- (TTL - Time To Live): , IP- . , IP-, , , 1 IP-, " " . "" .
- : IP- .
- : ( , ..).
IPv6 6. 4.
IP-: , , ,
TCP
TCP (Transmission Control Protocol) , . IP- 6. "TCP-". TCP-.
TCP | ||||
0 3 | 4 9 | 10 15 | 16 31 | |
(, ) | ||||
160/192+ |
: 16- , . , TCP, : 20/21 FTP; 22 SSH; 23 Telnet; 25 SMTP; 80,8080 HTTP, HTTP; 110 POP3; 194 IRC (Internet Relay Chat); 443 HTTPS (Secure HTTP); 8080 HTTP
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: 32- , TCP- . :
1. SYN, ISN (Initial Sequence Number), , , ISN + 1.
2. , SYN , , , .
: 32- TCP-, TCP-. ACK, , . .
: TCP- 32- TCP-. TCP 32- . 5 , 15, 20 60 . TCP.
(6 ) . (5- 6-) :
CWR (Congestion Window Reduced) , , ECE (RFC 3168)
ECE (ECN-Echo) ECN , ECN ( ) (RFC 3168)
( ) 6 :
- URG: = 1 , (urgent)
- ACK=1 , " " .
- PSH=1 , ,
- RST=1 , ( )
- SYN= 1 , TCP- .
- FIN= 1 , TCP- .
: , TCP-, TCP-. TCP- .
: 16- , , TCP-, .
: 16- , TCP-, (urgent) .
: TCP : ; (No Operation); .
UDP, , TCP :
, , . , , . , , .
, , , TCP . . , . , . , , .
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, , PSH, .
:
- FIN ACK .
- ACK, FIN, .
- ACK, .
, , . " " (sliding window), , , " " TCP-, . " " . , TCP- TCP-, .
, . .
UDP
UDP , IP. IP- 17. UDP- - . UDP-. UDP - "" . UDP: ; UDP- / ; , , , .
, TCP/IP:
Address Resolution Protocol, ARP. , IP- MAC-. ARP- arp IP-. *Routing Information Protocol, RIP. , RIP-. *Open Shortest Path First, OSPF. .
IP-
IP- - . () , -. IP- - , . IP- , .
- IP-, IP-.
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. IP-, - IP- IP- . , , - , IP. , . - , IP- , . , , , , . "" , , - .
ARP RARP
IP- IP- . , . IP- - ARP (Address Resolution Protocol, ).
, IP- (). ARP-, IP- . . ARP-.
ARP- , , ARP-.
IP- MAC-. RARP (Reverse Address Resolution Protocol). RARP ARP.
. : .
, (, ) , - / .
, "" . , , - . , , - .
Ethernet 1970- . Ethernet - , .
Ethernet :
: 64- , , -.
: 48- , Ethernet- .
: 16- , , Ethernet-. 0x0800 - IP.
: , , IP-. Ethernet 1500 . Ethernet- 64 (512 ).
: 32- , , .
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SLIP (Serial Line Internet Protocol) . SLIP , . SLIP- 0xEB(ESC), 0xC0(END). .
PPP (Point-to-Point Protocol) . PPP SLIP, SLIP, : ( IP); .