What is a MAC address?

Your I.D number, your birth date, social security number, your account number remains the same right? Of course it does these numbers are unique to you and it is similar to a MAC address.

Why do I say this? If you take your laptop to Boston Coffee company your I.P address is most likely to change however, your MAC address will remain the same and that is why it is called a physical address.

This physical address is burnt most probably the physical component either the mother board or the NIC card. So, it remains the same oh and b.t.w you need a MAC Address in order for your network device to have an I.P address. 

Ethernet address. What makes the MAC address qualify to identify it as an Ethernet Address? Let's just say we have got 3 client computers connected to a Layer 2 Cisco switch and b.t.w it is a Catalyst 2960 model. Now you have a Local Area Network, lets say you have 1 subnet and 1 VLAN. So what that means is that devices are on a local ethernet network, if we take it another step further it because it is all about MAC address for these computers to connect and communicate with the network.

48-bit Hexadecimal number unlike an I.P address where they only have decimal numbers a MAC address have numbers and alphabetics in them. This is how it looks BC08.8AFE.5592 and this is another way to write it out BC.08.8A.FE.55.92.

Hexadecimal numbers range from 0 - 9 and A - F where A=10 B=11 C=13 D=14 and F=15.

Th first 24 bits are assigned by IEEE which is a company an organization. So this organization will assign these 3 OCTETs. Then the vendor will assign the last 24 bits.

They are globally unique, this means there are no mac addresses that are the same period!