Reference
End-to-end
“End-to-end” refers to connectivity between the computers that engage in the
final communications.
(1)TCP
“TCP” is a protocol that corresponds to the transport layer (Layer 4) in the
OSI model. TCP provides reliable end-to-end communications.
It is equipped with the following functions to accomplish this role.
• Divides and assembles data into packets.
• Assigns a number (sequence number) to packets, indicating the sequence in
which the packets were divided.
• Uses numbers (port numbers) to identify the application software that
supports the data.
Port Number
Protocol
20, 21
Reference
IPv6
“IPv6” is an Internet protocol that provides expanded functionality over the
current Internet protocol (IPv4) used.
IPv6 expands the manageable address
space from 32 bits to 128 bits to address the shortage of available IP addresses caused by the rapid spread of
the Internet.
Other characteristics include faster routing, plug-and-play functionality, security
functions, multimedia support, and flexibility and expandability of functions.
Abbreviation for “Internet Protocol version 6.”
FTP
23
Telnet
25
SMTP
80
HTTP
(2)IP
“IP” is a protocol that corresponds to the network layer (Layer 3) in the
OSI model. Common functions of IP are “addressing” and “routing.”
●Addressing
IP uses a number called an “IP address” to identify the computer connected to a network. An IP address is a 32-bit number, and is divided into a
“network address” used to distinguish between multiple networks, and a
“host address” to distinguish computers within a network.
Network address
IP address
representation
Binary representation
160.
168.
1.
25
10100000
10101000
00000001
00011001
[IP address classes]
According to the scale of the network, IP addresses are divided into Class
A, Class B, and Class C. The structures of Classes A to C are shown below.
0
Class A
7 8
0
31
(7-bit)
Network address
8-bit
(24-bit)
Host address
24-bit
0
Class B
15 16
1
0
1
1
(14-bit)
Network address
16-bit
0
Class C
0
(21-bit)
Network address
24-bit
269
Host address
31
(16-bit)
Host address
16-bit
23 24
(8-bit)
Host address
8-bit
31