IST 228\Ch3\IP Addressing
What Is TCP/IP?
• A large collection of networking protocols and
services
• The Transmission Control Protocol (TCP)
handles reliable delivery for messages of
arbitrary size, and defines a robust delivery
mechanism for all kinds of data across a
network
• The Internet Protocol (IP) manages the routing
of network transmissions from sender to
receiver, along with issues related to network
and computer addresses, and much more
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IST 228\Ch3\IP Addressing
Origins of TCP/IP
• In 1969, the Advanced Research Projects Agency (ARPA),
a branch of the United States Department of Defense
(DoD), funded an academic research project for a special
type of long-haul network with following objectives:
– A desire to withstand a potential nuclear strike
– A desire to permit different kinds of computer systems
to easily communicate with one another
– A need to interconnect systems across long distances
• A packet-switched network, which is known as ARPANET,
was built as a result of this project
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IST 228\Ch3\IP Addressing
IP Addressing
• An IP address is a numeric identifier assigned
to each machine on an IP network
• IP address consist of 32 bits divided in to four
sections (octets)
• Usually depicted in one of three formats
Decimal:
172.16.30.56
Binary:
10101100.00010000.00011110.00111000
Hexadecimal: AC 10 1E 38
• 232=4,294,967,296 possible number of
addresses
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IST 228\Ch3\IP Addressing
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Binary-to-Decimal Conversion
Decimal
Binary
120,321
101010
+
100×1=
1
101×2=
20
102×3=
300
103×0=
0
4
10 ×2= 20,000
105×1= 100,000
120,321
Practice: Write IP address
10101100.00010001.00011000. 01010011
in decimal numbers.
+
20×0=
21×1=
22×0=
23×1=
24×0=
25×1=
00000000= 0
10000000= 128
11000000= 192
11100000= 224
11110000= 240
11111000= 248
11111100= 252
11111110= 254
11111111= 255
0
2
0
8
16
32
58
20 = 0
21 = 2
22 = 4
23 = 8
24 = 16
25 = 32
26 = 64
27 = 128
28 = 256
IST 228\Ch3\IP Addressing
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Hierarchical Addressing
• IP addressing is a hierarchical addressing
IP Pool
Network
Host
Host
Network
Sub-net
Host
Network
Sub-net
Host
• Hierarchical addressing makes sure
efficient routing
IST 228\Ch3\IP Addressing
Network Address Ranges
• Class A: the first bit of the first byte is always 0
(0xxxxxxx.)
– Range
• minimum 00000000. =0.
• maximum 01111111. =127.
– Format: network.node.node.node
– Valid Network Addressing
• 00000000.- is reserved for the default route for the network
• 01111111.- is reserved for diagnostics
• What is the maximum usable number of Class A network
addresses?
– Valid Host Addressing
• -.0.0.0 is reserved for network address
• -.255.255.255 is the broadcast address
• What is the maximum usable number of Class A node (hosts)
addresses?
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IST 228\Ch3\IP Addressing
• Class B: The first byte is always 1 and the second byte is always 0
(10xxxxxx.)
– Range
• minimum 10000000.=128.
• maximum 10111111.=191.
– Format: network.network.node.node
– Valid Host Addressing
• -.-.0.0 is reserved for the network address
• -.-.255.255 is the broadcast address
• What is the maximum usable number of Class B node (hosts) addresses?
• Class C: The first two bytes are always 1 (11xxxxxx)
– Range
• 11000000. = 192
• 11111111. = 223
– Format: network.network.network.node
– Valid Host Addressing
• -.-.-.0 is reserved for the network address
• -.-.-.255 is the broadcast address
• What is the maximum usable number of Class A node (hosts) addresses?
• Class D: Reserved for multicast address (224-239)
• Class E : Reserved for scientific purposes (240-255)
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IST 228\Ch3\IP Addressing
Subnetting
• Breaking a large network into smaller
networks
• Benefits
– Reduced traffic
– Optimize network performance
– Simplified management
– Helps expending the network
• To create subnetworks, bits from the host
portion is revered to define the subnet
address
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IST 228\Ch3\IP Addressing
Subnet Mask
• 32-bit information to distinguish the network and
host portions of the IP address
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IST 228\Ch3\IP Addressing
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Subnetting Class C
Binary
Subnet mask
Shorthand
Subnets on Hosts per
the
subnet
network
-.00000000
255.255.255.0
Default Subnet mask
-.10000000
255.255.255.128 /25
-.11000000
255.255.255.192 /26
2
62
-.11100000
255.255.255.224 /27
6
30
-.11110000
255.255.255.240 /28
14
14
-.11111000
255.255.255.248 /29
30
6
-.11111100
255.255.255.252 /30
62
2
Last two digits are reserved for hosts
Subnetting formulas
x=number of masked bits
Number of subnets on the network= 2x-2
Number of hosts per subnet=28-x-2
IST 228\Ch3\IP Addressing
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Example
Network address=192.168.10.0
Subnet mask=255.255.255.192
Subnet 64
01xxxxxx
01 000000=64
01 000001=65
01 111110=126
01 111111=127
The
The
The
The
network (192.168.10.64)
first valid host (192.168.10.65)
last valid host (192.168.10.126)
broadcast (192.168.10.127)
Subnet 128
10xxxxxx
10 000000=128
10 000001=129
10 111110=190
10 111111=191
The
The
The
The
network (192.168.10.128)
first valid host (192.168.10.129)
last valid host (192.168.10.190)
broadcast (192.168.10.191)
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Fast Way: Subnetting a Class C
1. Find the network addresses
Subnet mask=192
256-192=64 based number and
.64 is the first subnet
64+64=128 the second subnet
.128 is the second subnet
128+64=192 (subnetmask. Stop)
2. Find the broadcast address for each subnet
The number immediately preceding next subnet number
3. Find the valid host addresses
Valid host are numbered between the subnets.
192.168.10.64  192.168.10.65  192.168.10.126  192.168.10.127
The network
The valid host addresses
The broadcast address
Subnet 64
192.168.10.128  192.168.10.129  192.168.10.120  192.168.10.191
The network
The valid host addresses
Subnet 128
Network 192.168.10.0
Mask 255.255.255.192
The broadcast address
IST 228\Ch3\IP Addressing
Example
Network address=192.168.10.0
Subnet mask=255.255.255.224
The numbers of subnets and host? Network and Broadcast Addresses
for each subnet? Valid Host Addresses?
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IST 228\Ch3\IP Addressing
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Subnetting Class B
Binary
Subnet mask
Shorthand
-.0000000.00000000
255.255.0.0
Default Subnet mask
-.10000000. 00000000
255.255.128.0
/17
-.11000000. 00000000
255.255.192.0
/18
2
16,382
-.11100000. 00000000
255.255.224.0
/19
6
8,190
-.11110000. 00000000
255.255.240.0
/20
14
4,094
-.11111000. 00000000
255.255.248.0
/21
30
2,046
-.11111100. 00000000
255.255.252.0
/22
62
1,022
-.11111110. 00000000
255.255.254.0
/23
126
510
-.11111111. 00000000
255.255.255.0
/24
?
?
-.11111111.10000000
255.255.255.128
/25
510
126
-.11111111.11000000
255.255.255.192
/26
1,022
62
-.11111111.11100000
255.255.255.224
/27
2,046
30
-.11111111.11110000
255.255.255.240
/28
4,094
14
-.11111111.11111000
255.255.255.248
/29
8,190
6
-.11111111.11111100
255.255.255.252
/30
16,382
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Number of subnets on the network= 2x-2
Number of hosts per subnet=216-x-2
Subnets on the
network
Hosts per subnet
IST 228\Ch3\IP Addressing
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Example
Network address=180.168.0.0
Subnet mask=255.255.192.0
Subnet 64
01xxxxxx.xxxxxxxx
01000000.000000=64.0
The network (180.168. 64.0)
01000000.000001=64.1
The first valid host (180.64.1)
01111111.111110=127.254 The last valid host (180.168.127.254)
01111111.111111=127.255 The broadcast (180.168.127.255)
Subnet 128
10xxxxxx.xxxxxxx
10000000.000000=128.0
10000000.000001=128.1
10111111.111110=191.254
10111111.111111=191.255
The network (180.168. 128.0)
The first valid host (180.128.1)
The last valid host (180.168.191.254)
The broadcast (180.168.191.255)
IST 228\Ch3\IP Addressing
Example
•Network Address=172.16.0.0
•Subnetmask=255.255.240.0
The numbers of subnets and host? Network and Broadcast Addresses for each
subnet? Valid Host Addresses?
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IST 228\Ch3\IP Addressing
Example
•Network Address=172.16.0.0
•Subnetmask=255.255.255.192 (/26)
The numbers of subnets and host? Network and Broadcast Addresses for each subnet?
Valid Host Addresses?
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