ARP address Resolution Protocol & lt;-gt;-- address Resolution

Introduce:

First, there are two key concepts, one is Internet communication, which is done by sending data at layer 3 using the network layer address, and the other is the actual transmission of the data, which occurs at layer 2 using the data link layer address.

Second, you need to know what layer 2 and layer 3 addressing is?

There are two layers when it comes to addressing, that is, the data link layer and the network layer.

Layer 2 address: it can be used for local direct transmission between hardware devices for communication, and can be used to implement basic LAN, WLAN, WAN technologies.

Layer 3 address: it is used in the Internet to create an equivalent huge virtual network at the network layer.

The important difference between layer 2 addresses and layer 3 addresses: layer 2 involves directly connected devices in the same network, while layer 3 involves indirectly connected devices and directly connected devices.

Transmission at each hop (when a request is sent using an IP address, only one hop at a time, from one physical network to another): the actual transmission occurs at the data link layer and the physical layer

Why address resolution?

Because the logical communication of the device on the network is at the layer 3 address, but in practice, the device transmission uses the layer 2 address, so there is no direct correspondence between the two addresses, so it is necessary to find a way to achieve the translation between layer 2 address and layer 3 address.

General address resolution methods:

1. Direct mapping

2. Dynamic analysis