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Телекомуникациски склопови и уреди
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.- ,
Glava 6-1
6
6.1
Advanced Research Projects Agency (R)
1960- . ,
: ,
.
..
, , ,
. "
R IP (Information
Processing Techniques Office) h Licklider
.
-
.
-
.
time-sharing,
.
. 1963
.- ,
Glava 6-2
I&IP (Compatible Time
Sharing System), Licklider .
time-sharing
,
. time-sharing
, time-sharing
,
. 1966
,
dial-up .
Paul Baran
Rand tion Donald Wats Davis National Physical Labaratory,
Davis "packet-switching
" . ket-switching
r-t-r ,
.
,
, ,
() ,
.
,
.
IP :
RAND, University of California Santa Barbara (U), Stanford Research Institute (RI),
University of Utah University of California in Los Angeles (UCLA) 1968
kt-switching network.
1969 Bolt Beranek & Newman
(N), Cambridge Massachusetts Company.
-
( )
.
.- ,
Glava 6-3
,
.
1 1969 K I
(Interface message processor) UCLA, UCSB, SRI
University of Utah. .
packet-switching Davis 1961
R, ,
RNET.
.
(network working)
1996 .
,
(Telnet)
(File Transport Protocol - F),
NCP (Network Control Protocol).
1971 15
. ARPANET
( , Ray Tomilson .).
RN N
(/IP) 1982 .
RPANET ,
1978 packet-switching,
. packet-switching -
USN 1978 .
USENET
: N, N
MSFN. NSFN
/IP
. 5
()
"backbone".
packet-switching . ,
.- ,
Glava 6-4
,
,
.
IP ,
. ket-switching
(User Friendly) .
(t nsfer
tol), RN (Conseil Europeen pour la Recherche Nucleaire),
WorldWideWeb - l for a HyperText project,
WWW.
1990 .
.
.
.
6.2 OSI
, .
.
(
, ) .
,
, , ( ,
).
, .
.- ,
Glava 6-5
,
. .. OSI (Open System for Interconnection) ,
:
(application layer) (presentation layer) (session layer) (transport layer) (network layer) (data layer) (physical layer)
, TCP/IP UDP
5 , OSI 5 7
, . IP,
TCP UDP .
OSI 1 2. 6.1 OSI
.
(Transmision Control tl) IP (Internet tl).
IP,
OSI ,
(Simple Mail Transport 1l), N (Simple Network Manage tl), F
(File Transfer Protocol), Telnet (Terminal emulation protocol)
R (Remote Procedure Call), XDR
(External Data Representation) NFS (Network File System).
- I UDP (User
Datagram Protocol),
,
.
IP ( ) 6.1.
.- ,
Glava 6-6
OSI
NF
XDR F, 1net, ,N,R
RPC
, UD
I
RP, RARP
6.1 OSI
()
, ( OSI )
.
:
(hosts), . ,
.
.
.
Hub . .
. Hub-
.
.
(bridges), .
(Local Area Networks LAN).
.
I
.- ,
Glava 6-7
. OSI.
MAC .
(switch), .
Switch-
.
.
(routers), .
. .
(, )
. .
(TCP, UDP, IP )
, .
6.2 OSI ()
( )
.
()
.
PSDU (PLCP Service Data Unit)
MAC H
PHY ( )
MSDU (MAC SDU)
LLC H
H IP
TCP
HTTP
HTML
MAC (Medium Access Control)
LLC (Logical Link Control)
IP
TCP
HTTP
IEEE 802 ()
TCP/IP
PHY H
.- ,
Glava 6-8
(, ) ,
( 6.2).
, ,
, .
: LAN (Local Area Network), MAN (Metropolitan Area Network), WAN
(Wide Area Network), , .
LAN
LAN
LAN
6.3
( 6.3).
.
IP ,
.
.- ,
Glava 6-9
.
, .
(IP Internet Protocol) .
,
(
).
IP ,
IP .
() IP
. (, )
, IP .
.
.
( IP )
(gateways),
internetworking .. .
.
,
,
().
6.3 - IP
.
(
) .
.- ,
Glava 6-10
IP
. IP
.
IP , : IP version 4 (IPv4),
RFC 791, IP version 6 (IPv6), RFC 1883-1887. IP
:
IP . IP ()
;
IP IP ;
;
IP ( ) ,
.
IPv6 IPv4.
(..
IP ).
6.3.1 IP 4 (IPv4)
IP . IPv4
20 .
MSB (Most
significant bit) LSB (Least significant bit) ,
.
.- ,
Glava 6-11
6.4 IP IPv4
6.4 IPv4 .
IP IPv4,
.
IP .
(Version)
( 4 6, .. IPv4 IPv6).
(
), IHL (Internet Header Length)
, 32 (.. 1 = 4 ).
5 ( 5 4 = 20 ),
, 60 .
(Type of Service S)
, ,
. . ,
(
), ,
. File Transfer,
. ToS 3 Precedence , 3
: Delay, Throught Reliability.
,
( bit/sec).
(Type of Service-ToS)
0 4 8 16
19
(Time To Live-TTL)
(Header Checksum)
24 31
IP (Source address)
IP (Destination address)
(padding)
32 = 4 (1 = 8 )
5x4=20
.- ,
Glava 6-12
, default, .
(, , e-
mail .),
, best-effort. ,
best-effort .
(Total Length)
. , 16 ,
65535 (64 kB), .. 0 (216-1).
(Fragment Identification)
,
,
, .
(Flags) 3
.
.
. .
(Fragment Offset)
, I ,
, .
. 13 , 8192
, 64kB.
(Time to Live)
.
hop- .
TTL ,
. 0,
.
,
,
.
.- ,
Glava 6-13
, IP
( TCP, UDP
). (Protocol) .
(Header Checksum)
IP .
,
( Time to Live )
.
IP (Source Address) - IP
.
IP (Destination Address) - IP
, IP .
(Options) ,
. ,
,
. Options .
,
.
6.3.2 IP 6 (IPv6)
IPv6 IPv4. IPv6
. IPv6
128
32 IPv4. , IPv6
IP
( 7 Network Address Translation).
IPv6
IPv6 . IPv6 6.4.
.- ,
Glava 6-14
6.4 IPv6
IPv4,
IP 4.
IPv4, IPv6 QoS (Quality of Service)
. ( ,
, /)
, ( ) IP .
(flow labels)
, IP end-to-end QoS
.
IPv6 .
.
.
. IPv6
(payload length)
0 8 16
(hop)
24 31
(Source Address)
: IPv6 128 , 4 IPv4 .
(Destination Address)
4 12
32 = 4 (1 = 8 )
10x4=40
.- ,
Glava 6-15
IPv4
.
IP IPv6
( , IPv4
Header Checksum, TTL )
.
.
IPv6 IP
4 128 32
IPv4.
(Hop) 8- TTL
IPv4.
, , IPv6 IP
IPv4.
, IPv6 ,
, IPv6 ,
IPv6 . IPv6
, IP.
IPv6 40 .
IP
IPv6 IPv4 ( 20
), . ,
(
IP)
,
IPv6 IPv4.
6.3.3 IPv6 IPv4?
IPv6 IPv4 .
. IPv6
.- ,
Glava 6-16
IPv4
,
.
IPv6 ,
.
IPv4
IPv4 . plug-and-play
IPv6
IPv4
. IPv6
IPv4 IPv6 (.
IP ).
IPv6 stacks IPv4 stack
IPv6 stack.
IPv6 IP ,
IPv6. . IPv6
IPv4
IPv6
QoS .
6.4 IP
( IP )
IP . IP
. /IP ,
32 :
(network number) (host number).
.- ,
Glava 6-17
,
, Network Information Center (NIC).
, NIC ,
IP
.
IP 32 ( IPv4,
IP IPv4 ), 4 ,
( 194.149.144.1).
0, 255.
IP 5 , , , D .
, .
, 6.5.
6.5 IPv4
IP . IP
126 16 ; B
16382 65534 ; C 2 254 .
, . , C
255 ().
,
5 IP (classful IP addresses):
A: 7- /24- 0xx 0 126
loopback ( IP ) 127
B: 14- /16- 10x 128 191
C: 21- /8- 110x 192 223
D: 1110x 224 239
E: 1111x 240 254
broadcast () 255.255.255.255
.- ,
Glava 6-18
7 , C 21
,
.
D . IP ,
D.
.
,
.
E .
, IPv4 / -
ID ( ) ID (
).
32 unicast .
, B C , .
IPv4 . 1990- .
IPv4
.
Classless Inter-Domain Routing (CIDR)
.
.
.
IP (CIDR) IP 64
:
IP 32 , (mask) 32 .
, IP ,
, IP
IP . ,
:
.- ,
Glava 6-19
1) a.b.c.d/255.255.255.0 ( ,
IP );
2) a.b.c.d/24 (
32- , - /24
255.255.255.0, 24
IP 1)
IP :
IP = 10.24.17.198 / 255.255.248.0 (IP / IP )
0A.18.11.C6 0A.18.11.C6
FF.FF.F8.00 00.00.07.FF
0A.18.10.00 00.00.01.C6
= 10.24.16.0, IP = 0.0.1.198
6.5 IP
IP (, )
(, ).
IP .. . IP
.
.. IP
IP ,
IP ,
IP . IP
(.. IP )
IP (..
IP ) , IP ()
(
).
.- ,
Glava 6-20
:
() ,
.
, (.. ):
( 2 layer 2): ( direct delivery)
o , IP ()
.. (:
), IP
o ?
IP ,
.
( 3 layer 3): (store and forward):
( indirect delivery)
o ,
(
TTL > 0)
o ?
.. (table-driven routing).
,
(next-hop routing),
IP . , :
(default routes) .
() IP
. ,
.- ,
Glava 6-21
(
).
6.6.
6.6 ()
, ,
. ,
. , IP ,
( , ),
( , ).
IP ,
IP .
IP
RouteDatagram (Datagram, RoutingTable)
IP D N;
if N ( IP )
D
else if host-specific D
else if N
else if default
default
else (routing error);
.- ,
Glava 6-22
10.0.0.0
30.0.0.0
50.0.0.0
80.0.0.0
10.0.0.2
30.0.0.5 30.0.0.9
50.0.0.5 50.0.0.6
80.0.0.1
- - -
( ) ( )
30.0.0.5
30.0.0.050.0.0.0.10.0.0.080.0.0.0 50.0.0.6
-
6.7 IP
6.7
. 4 . ,
. IP
30.0.0.0 50.0.0.0 ( ,
, IP ), , ,
IP 30.0.0.0
IP
(MAC Medium Access Control ) , IP
( ,
),
. ,
IP 10.0.0.0,
IP
30.0.0.5 , .
(
).
.
.
( ) :
.- ,
Glava 6-23
, IP IP
IP , IP
( 6.2);
IP , IP ( ,
, , WiFi .).