This document covers the fundamentals of computer network servicing, focusing on IP addressing, subnetting, and the roles of routing and switching in data networks. It details the various classes of IP addresses (A to E), their usage, and the concept of network address translation (NAT) to maintain unique addressing within private networks. Additionally, it includes activities for students to apply their knowledge in identifying classes, network, and host addresses.

1. Computer System
Servicing NCIIIP ADDRESSING
MARVIN B. BROÑOSO
CSS TEACHER/TRAINER
09186975164

2. Learning Competencies
After this learning module the students will be able to . . .
◦ ○ Learn and discuss network addressing, switching and routing.
◦ ○ Identify and understand the IP Addressing format
◦ ○ Understand the explain the Network address translation and IPv6

3. Two most important function in a data
network are:
To uniquely identify each host or computer or device participatingin
network. This is called addressing.
To be able to connect and move data packets between any devices in
a network. This is often called switching and routing by connecting
devices to switches and routers respectively.
An IP address and Subnet Mask are very basic entities of data
network.

4. IP ADDRESS
An IP address is a 32 bit number like
11000000101010000000000100000001 in binary or 3232235777 in
decimal. So it is written in 4 parts like
11000000.10101000.00000001.00000001 in binary form and
192.168.1.1 in decimal form. This way it is easier to understand.
Now, a unique number is sufficient to identify each host in a network
but that alone cannot help in reaching from one host to another.
Imagine if every house in world had a unique number or some name,
but no state, city and country info. Would it be possible to reach a
particular house even if its number is known?

5. SUBNET MASK
“Subnet” means sub-network. So the purpose of subnet mask was
to create another partition (3rd part) in an IP Address after
network part.

6. IP Address Format

7. EXCLUSION
Some address ranges are excluded from the above classes. All
addresses of the form 127.xx.yy.xx are used for diagnostics. The
followingaddress ranges are designated as "private": meaning thay
can only be used on networks which are not connected to the global
Internet:
10.0.0.0 - 10.255.255.255
172.16.0.0.0 - 172.31.255.255
192.168.0.0 - 192.168.255.255

8. IP CLASS A
Class A addresses always have the first bit of their IP
addresses set to “0”. Since Class A networks have an 8-bit
network mask, the use of a leading zero leaves only 7 bits
for the network portion of the address, allowing for a
maximum of 128 possible network numbers, ranging from
0.0.0.0 – 127.255.255.255. Number 127.x.x.x is reserved for
loopback, used for internal testing on the local machine.
0.0.0.0 – 127.255.255.255
IP addresses that can be assigned to devices
and computers.

9. IP CLASS B
Class B addresses always have the first bit set to “1” and
their second bit set to “0”. Since Class B addresses have a
16-bit network mask, the use of a leading “10” bit-pattern
leaves 14 bits for the network portion of the address,
allowing for a maximum of 16,384 networks, ranging from
128.0.0.0 – 191.255.255.255.
128.0.0.0 – 191.255.255.255
These blocks are generally allocated to Internet Service
Provider and large networks, like college or hospital.

10. IP CLASS C
Class C addresses have their first two bits set to “1” and
their third bit set to “0”. Since Class C addresses have a 24-
bit network mask, this leaves 21 bits for the network
portion of the address, allowing for a maximum of
2,097,152 network addresses, ranging from 192.0.0.0 –
223.255.255.255.
192.0.0.0 – 223.225.255.225
IP Address for small to mid-sized companies

11. IP CLASS D
Class D addresses are used for multicasting applications.
Class D addresses have their first three bits set to “1” and
their fourth bit set to “0”. Class D addresses are 32-bit
network addresses, meaning that all the values within the
range of 224.0.0.0 – 239.255.255.255 are used to uniquely
identify multicast groups. There are no host addresses
within the Class D address space, since all the hosts within a
group share the group’s IP address for receiver purposes.
224.0.0.0 – 239.255.255.255
Reserved for a service called Multicast

12. IP CLASS E
Class E addresses are defined as experimental and are
reserved for future testing purposes. They have never been
documented or utilized in a standard way.
240.0.0.0 – 255.255.255.255
IP Address reserved for experimental use.

13. Network Address Translationand IPv6
Network Address Translation is a technique which allows for the
composition of a network to be completely hidden from the outside
world, with the entire network identified by a single IP address.
Within the network, hosts and routers have addresses which are
unique to that network, typically taked from the ranges designated
as "private“. In order to make sure that responses get back to the
right hosts when packets are sent out into the Internet, the router
will construct a table associatingoutgoing packets with private IP
addresses; the address of the relevant table entry will be stored in
the packet itself.

14. ACTIVITY
Examples
Find the class, network and host addresses for:
4.23.145.90
227.34.78.7
246.7.3.8
129.6.8.4
198.76.9.23