Chapter 4: IP Addresses
The network layer is located between the data link layer and the transport layer. The network layer contains many protocols, the most important of which is the IP protocol. The network layer provides IP routing functions. To understand IP routing, in addition to being familiar with the working mechanism of the IP protocol, you must also understand IP addressing and how to use IP addresses reasonably to design networks.
After studying this chapter, we should be able to:
- Master the fundamentals of IP
- Master IP address configuration
- Master VLSM
4.1 Introduction to IP address
The protocol family adopted by the current global Internet is the TCP/IP protocol family. IP is the protocol of the network layer in the TCP/IP protocol suite, and is the core protocol of the TCP/IP protocol suite. The IP protocol defines an address code, called an IP address, which is the code of the network segment, network device interface, and host in the network. It is not a physical address, but a logical address, that is, the address can be assigned, and Non-fixed and modifiable.
IPv4, the fourth version of the Internet Protocol (IP), is also the first widely used protocol that forms the cornerstone of today's Internet technology. 1981 Jon Postel in RFC791