Chapter IV Household Registration address of the computer-ARP

ARP provides dynamic mapping between IP addresses and physical hardware

ARP is a dynamic mapping between 32bit's ip address and hardware using different network technologies.

The length of ARP data frame is 42 bytes.

The ARP request is broadcast, but the ARP reply is unique

Communication between different networks, using the router as the delegated ARP or ARP agent to achieve the connection

In most T C P / I P implementations, A R P is a basic protocol, but it runs for applications or systems

Generally speaking, the manager is transparent. The A R P cache is very critical in its operation, and we can use the a r p command to control the high

Quick cache for inspection and operation. Each item in the cache has a timer that removes incomplete and

The complete table item. The a r p command displays and modifies the contents of the A R P cache

Common sense:

Packet is in the process of communication transmission, which is generally called "packet". It works on the third layer (network layer) and the fourth layer (transport layer) of the OSI model, and the frame works in the second layer (data link layer). The content of the upper layer is transmitted by the content of the next layer, so in the local area network, the "packet" is included in the "frame". The so-called data frame (Data frame) is the protocol data unit of the data link layer, which consists of three parts: the frame header, the data part and the frame tail. The header and trailer of the frame contain some necessary control information, such as synchronization information, address information, error control information, etc., while the data part contains data transmitted from the network layer, such as IP packets.