Difference between physical address and logical address in networking

Physical Address : 

Physical address is a hardware level address which actually uniquely identify your device at data link layer. This address stored by manufacturer in NIC (Network Interface Card). You can't change this address because it's stored in ROM of NIC card. This address is of 48 bits and divided in to two parts. First 24 bits are assigned for OUI ( Organisationally Unique Identifier ) and last 24 bits identify that device interface.

In this Example first 24 bits that means 0A-00-27 are for OUI and last 24 bits 00-00-15 are for network controller Interface unique identifier.

Logical Address :

Logical Address is also known as IP address.It is changeable. IP address is working at network layer. Logical address is given by two ways.First, Statically and second dynamically. Network administrator or user can assign this address manually to the system.

DHCP ( Dynamic host configuration protocol ) used to assign dynamically IP address to the system. There are different versions of IP addressing.Most popular one is IPv4 which is obsolete and the latest one is IPv6.If you are using IPv4 addressing scheme the it's of 32bits. If you are using IPv6 then it's of 128 bits.