Addressing

Address 

Physical Address or MAC Address or Hardware Address

Physical address is of 48 bits.

48 bits divide into 2 parts, 24 bits and 24 bits.

First 24 bits denote Company Identification.

Second 24 bits denote serial number provide by company.

It represented into Hexadecimal (12 Hexadecimal Character).

It is globally unique.

It is available into NIC.

Logical Address or IP Address

It is managed by IP.

It provides unique identification to network devices using a combination of number.

It helps in establishing different networks.

It is available into 2 versions

· IPv4
It has 32 bits divided into 4 groups.

Each having 8 bits.

It supports unicasting, multicasting and broadcasting.

It is represented into (.) doted decimal notation.

Each group is separated by (.) dot.

It supports approx 3.2 million IP addresses.

These addresses are divided into 5 classes.
These classes are A, B, C, D and E.

Class A
· First octet of IP contains 0 to 127 IP series.

· Total number of IP series – 128.

· Host in each series – 16777214.

· Default subnet mask – 255.0.0.0

· First octet contains Network ID and 3 octets contain Host ID.

Class B
· First octet of IP contains 128 to 191 IP series.

· Total number of IP series – 16384.

· Host in each series – 65536.

· Default subnet mask – 255.255.0.0

· First 2 octets contain Network ID and 2 octets contain Host ID.

Class C
· First octet of IP contains 192 to 223 IP series.

· Total number of IP series – 2097152.

· Host in each series – 254.

· Default subnet mask – 255.255.255.0

· First 3 octets contain Network ID and 1 octet contains Host ID.

Class D
· First octet of IP contains 224 to 239 IP series.

· It is used for multicasting.

Class E
· First octet of IP contains 240 to 255 IP series.

· This class is not in use.

o Private IP series

In class A – 10.0.0.0 to 10.255.255.255 (1)

In class B – 172.16.0.0 to 172.31.255.255 (16)

In class C – 192.168.0.0 to 192.168.255.255 (256)

o Reserved IP series

In class A – 0.x.x.x – Default route

In class A – 127.x.x.x – Loop Back Testing

In class B – 169.254.x.x – APIPA

All rest IP address in class A, B and C are public IP address. 

Sub-netting

o It is the technique to break a series of IP into small subnets (groups).

o It is done by changing the value of default subnet mask.

CIDR (Classless Inter Domain Routing)
o It is a technique to represent IP address and subnet mask in / notation.

o Total ON bit into subnet mask become IP prefix.

VLSM (Variable Length Subnet Mask)
o It is a technique to break a series of IP into different subnet mask as per the actual requirement of network.

Super netting:-
o It is a technique to join two or more series of IP (mostly in Class C) to form a big network.