CCNA- IP address

IP ADDRESS..............

IP address is a logical address which is assigned to networking devices for their identity. Using IP address we access resources from one device to another device.

There are two version of IP address.

1--IP version 4

2--IP version 6

IP VERSION 4--

It is a 32 bit logical address written in dotted decimal. It is used to identify devices in a network . It has two part network ID and Host ID . Network ID indicates an unique ID for network and Host ID indicates device ID in network.

There are five classes in IPv4 according to size of network and purpose.

Class A- 1.0.0.0 - 126.255.255.255

• In A class IP, 8bit is for NID and 24 bit for Host ID.
• Default Subnet mask for this is 255.0.0.0
• Total Subnet in A Class IP is 2⁷-2=126
• Host per Subnet = 2²⁴-2 = 16777214
• Private IP - 10.0.0.0-10.255.255.255

Class B- 128.0.0.0 - 191.255.255.255

• In B class IP 16bit for NID and 16 bit for Host ID.
• Default Subnet mask for this is 255.255.0.0
• Total Subnet in B Class IP is 2¹⁴ -2=16382
• Host per Subnet = 2¹⁶ -2=65534
• Private IP - 172.16.0.0 - 172.31.255.255

Class C- 192.0.0.0 to 223.255.255.255

• In C class IP 24bit is for NID and 8 bit for Host ID .
• Default Subnet mask is 255.255.255.0
• Total Subnet in C class IP is 2²¹ -2= 2097152
• Host per Subnet = 2⁸-2=254
• Private IP - 192.168.0.0- 192.168.255.255

Class D- 224.0.0.0- 239.255.255.255

D class is reserved for multicasting

Class E- 240.0.0.0 - 255.255.255.255

E class is reserved for research

Special IP addresses...

APIPA (Automatic Private Internet Protocol Address ) -----

It is assigned to devices Automatically when no DHCP server is active in network and static IP address has not been configured too. APIPA ranges from 169.254.0.0 to 169.254.255.255.

Loopback Address- Loopback address is for Loopback test of devices. Reserved address is 127.0.0.1

Default Broadcast Address- 255.255.255.255

Private IP -

Private IP address is free to use. We can use this IP without any permission of ISP. Private can only be routed in private Network . We can share and access resources in private network only.We can connect our private computer to public network using a router or Server . We will have to configure NAT on Server or Router.

There are two type of IP addresses are used.

1- Class full address- When we use default subnet mask with IP address , This is known as Class full address. Class A, Class B and Class C addresses are class full addresses.

2- Class less addresses- When we use subnetted Address and new subnet mask . We do not follow Class . This is known as Class less addresses.

Follow this table to know block size and subnet mask.