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4
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2014
4
TCP/IP Cisco Packet Tracer ( 2)
1.1. .
1.2 TCP/IP DHP, ICMP ARP.
1.3 Cisco Packet Tracer.
.
́ .
/ .
, , :
(1- OSI)
(2- OSI)
(3- OSI)
.
, TCP/IP, , . , . ( CIDR ):
192.168.1.0/24, 192.168.2.0/24, 192.168.3.0/24 . . 254
192.168.0.0/25, 192.168.128.0/26, 192.168.172.0/27 126, 62, 30
23 .
RFC 4632(.) Classless Inter-domain Routing (CIDR): The Internet Address Assignment and Aggregation Plan
,
(router) , , (). . - ( ).
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, , , , . , .
, :
- ;
- - -;
- .
, , , . , .
, , , , , . , , / . .
, . , , , . . , . :
192.168.64.0/16 [110/49] via 192.168.1.2, 00:34:34, FastEthernet0/0.1
192.168.64.0/16 ,
110/-
/49 ,
192.168.1.2 ,
192.168.64.0/16,
00:34:34 , ,
FastEthernet0/0.1 ,
192.168.1.2.
:
, . , . , .
, RIP, OSPF, EIGRP, IS-IS, BGP, . , , , . . , . . , , , .
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.
, , . , , Ethernet WAN-, xDSL, PPP . . , .
Network layer
- OSI.
. , , , . , .
IP (. Internet Protocol ) , TCP/IP.
IP (RFC 791) ( ) . , ( OSI) . , , , . () OSI , TCP IP .
IP , IPv4. IP IP- 4 ( , ). . , , ( A, B, C; , ).
IPv6, , IPv4. , . IPv4 IPv6 . 2007 760 , IPv6. , IPv4 203 , IPv6 , IPv4.
IP- , . , , - , , . .
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2.1 IP- ()
(VERS) IP. 4 6, IPng (IP next generation) IPv6.
(HLEN) IP 4 , 32- . 20 ( 32- ), (IP OPTIONS).
(SERVICE TYPE) 1 . (PRECEDENCE). 0 ( ) 7 ( ). . , . D (delay) , , , R .
(TOTAL LENGTH) 2 .
(IDENTIFICATION) 2 , . .
(FLAGS) 3 , ( Do not Fragment DF ), , ( More Fragments MF , ).
(FRAGMENT OFFSET) 13 , , . / .
(TIME LIVE) 1 , . IP. ; ( ). .
(PROTOCOL) 1 (, TCP, UDP RIP).
(HEADER CHECKSUM) 2 ; .
(SOURCE IP ADDRESS) (DESTINATION IP ADDRESS) 32 .
(IP OPTIONS) . , . , , , . , 32- .
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, , 65535 , , IP-. Ethernet, 1500 , Ethernet.
TCP/IP , , IP- , . , IP- 12.34.56.78 255.255.0.0 12.34.0.0.
, IP- , ( ). , :
IP-: 00001100 00100010 00111000 01001110 (12.34.56.78)
: 11111111 11111111 11100000 00000000 (255.255.224.0)
: 00001100 00100010 00100000 00000000 (12.34.32.0)
IP- CIDR ( IP-/ ).
.
ARP
Ethernet IP MAC . , , , IP- , IP- . ARP- , (. 2.2).
2.2 ARP-
ARP - (Address Resolution Protocol) () OSI, IP- MAC-, . ARP RFC 826 1982 .
IP MAC ARP-, IP MAC .
ARP- Windows 2.3.
ARP-, IP MAC , , :
, , .
. ( 2 ), . ARP- . , . ARP-.
2.3 ARP-
RARP (. Reverse Address Resolution Protocol - ) - () OSI, , IP-.
2.4 RARP-
ARP-:
ARP-(ARPrequest);
ARP-(ARP reply);
RARP-(RARP-request);
RARP-(RARP-reply).
2.5 ARP
Hardware type (HTYPE) , . , Ethernet 0x0001
Protocol type (PTYPE) . , IPv4 0x0800
Hardware length (HLEN) . Ethernet 6 .
Protocol length (PLEN) . IPv4 4 .
Operation : 1 2 .
Sender hardware address (SHA) .
Sender protocol address (SPA) .
Targethardwareaddress (THA) . .
Target protocol address (TPA) .
1. .
2. , ?
3. ? ?
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4. .
5. . ?
6. ?
7. ? ?
8. ?
9. IP?
10. P-.
11. ARP RARP?
4.1 3.
4.2 , .5.