So, the recipients’ names of our letters are still the same. But moving home does not implicate changing names. In the same scenario, our friends can sometimes move from one house to another, which will change the recipients’ addresses of our letters. Thus, the postman uses the recipient’s name to deliver the letter to the correct person at the provided address. However, the address does not define who lives there. With the recipient’s address, the postman knows where to take the letter. So, for both sender and recipient, we must include a name and an address.

Let’s work with an analogy to understand better the differences and relations between IP and MAC: we are sending a letter to a friend. An IP address identifies a networked entity, not a device (it is related to the location of a device, not the device itself).

However, IP has two particular characteristics that differentiate it from MAC: In the previously described conditions, an IP address has a similar purpose to a MAC address: identify a networked entity, enabling it to communicate with other networked entities. Thus, a NIC can accept the frame based on another criterion, such as using a multicast address list. Otherwise, if the I/G bit is one (1), we have a multicast address. So, a NIC will accept the frame only if the destination MAC of it perfectly matches the NIC’s. If the I/G bit is zero (0), we have a unicast address, and the frame has a single destination. The very first bit, called bit zero or I/G bit, determines if an address is unicast or multicast.Ĭomputers define this bit when sending a frame through the network. In the first byte of the first part of a MAC address, we have two special bits: the first and the second. Each digit, in turn, can have values from zero (0) to nine (9) and from A (10) to F (15).įurthermore, there exist two major parts in MAC addresses: the manufacturer identification (first three bytes) and a unique number defined by the manufacturer that identifies a particular device in a network (last three bytes). So, for each byte, we’ll have a two-digit number. MAC addresses are formed by six bytes containing hexadecimal numbers.

Mac address