IP , IP classes, IP Structure, Gateway, router, private IP, DHCP configuration, subnet, masking, Subnetting, Understanding Network Classes, Understanding Subnetting, Dynamic Host Configuration Protocol

1. IP Networking

2. Objectives
 IP
 Understanding Network Classes
 Understanding Subnetting
 Gateways and Routers
 Dynamic Host Configuration Protocol

4. IP structure
 IP addresses consist of four sections
 Each section is 8 bits long
 Each section can range from 0 to 255
 Written, for example, 128.35.0.72

5. IP Classes (continued)
 Class A
 Reserved for governments and large
corporations throughout the world
 Each Class A address supports 16,777,214 hosts
 Class B
 Addresses are assigned to large- and medium-
sized companies
 Each Class B address supports 65,534 hosts
5

6. IP Classes (continued)
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7. IP Classes (continued)
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•
•
Class C
– Addresses are assigned to groups that do not meet
the qualifications to obtain Class A or B addresses
– Each Class C address supports 254 hosts
Class D
– Addresses (also known as multicast addresses) are
reserved for multicasting
– Multicasting is the sending of a stream of data
(usually audio and video) to multiple computers
simultaneously

8. IP Classes (continued)
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9. 9
IP Classes (continued)
•
•
Class E
– Addresses are reserved for research, testing, and
experimentation
– The Class E range starts where Class D leaves off
Private IP ranges
– Many companies use private IP addresses for their
internal networks
• Will not be routable on the Internet
– Gateway devices have network interface connections
to the internal network and the Internet
• Route packets between them

10. IP Classes (continued)
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11. IP structure
 5 Classes of IP address A, B, C, D, and E
 Class A reserved for governments.
 Class B reserved for medium companies.
 Class C reserved for small companies.
 Class D are reserved for multicasting.
 Class E are reserved for future use.

12.  Class A addresses begin with 0xxx, or 1 to 126 decimal.
 Class B addresses begin with 10xx, or 128 to 191 decimal.
 Class C addresses begin with 110x, or 192 to 223 decimal.
 Class D addresses begin with 1110, or 224 to 239 decimal.
 Class E addresses begin with 1111, or 240 to 254 decimal.

13. RESERVED NETWORK
NUMBERS
Network Class Netmask Network Addresses
A 255.0.0.0 10.0.0.0–10.255.255.255
B 255.255.0.0 172.16.0.0–17.31.255.255
C 255.255.255.0 192.168.0.0–
192.168.255.255

14. Subnet Mask
 An IP address has two components, the network address and
the host address.
 A subnet mask separates the IP address into the network and
host addresses (<network><host>).
 Subnetting further divides the host part of an IP address into a
subnet and host address (<network><subnet><host>).
 A Subnet mask is a 32-bit number that masks an IP address.
 It is called a subnet mask because it is used to identify
network address of an IP address by performing bitwise AND
operation on the netmask.

15. Subnet Mask (contd..)
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16. Contd..
 Applying a subnet mask to an IP address separates network address from host address.
 The network bits are represented by the 1's in the mask, and the host bits are represented by
0's.
 Performing a bitwise logical AND operation on the IP address with the subnet mask produces
the network address.
 For example, applying the Class C subnet mask to our IP address 216.3.128.12 produces the
following network address:
IP: 1101 1000 . 0000 0011 . 1000 0000 . 0000 1100 (216.003.128.012)
Mask: 1111 1111 . 1111 1111 . 1111 1111 . 0000 0000 (255.255.255.000)
---------------------------------------------
1101 1000 . 0000 0011 . 1000 0000 . 0000 0000 (216.003.128.000)

17. Router
 A router is a networking device that forwards data packets
between computer networks.
 Routers perform the traffic directing functions on the Internet.
 Then, using information in its routing table or routing policy, it
directs the packet to the next network on its journey.
 A router is connected to at least two networks, commonly two
LANs or WANs or a LAN and its ISP’s network.

18. Gateway
 A gateway is a network point that acts as an entrance to
another network.
 It act like protocol translation/mapping gateway
interconnects networks with different network protocol
technologies by performing the required protocol
conversions.
 The gateway node often acts as a proxy server and a
firewall.
 The gateway is also associated with both a router, which
use headers and forwarding tables to determine where
packets are sent, and a switch, which provides the actual
path for the packet in and out of the gateway.

19. DHCP
 The Dynamic Host Configuration Protocol (DHCP) is a
network protocol that is used to configure network devices so
that they can communicate on an IP network.
 It is a protocol for assigning dynamic IP addresses to devices
on a network.
 With dynamic addressing, a device can have a different IP
address every time it connects to the network.
 In some systems, the device's IP address can even change
while it is still connected.
 DHCP also supports a mix of static and dynamic IP addresses.

20. Contd..
 Dynamic addressing simplifies network
administration because the software keeps
track of IP addresses rather than requiring an
administrator to manage the task.
 This means that a new computer can be
added to a network without the hassle of
manually assigning it a unique IP address.