Class C Network

What Does Class C Network Mean?

A class C network is the most common of the five computer network classes, designated as A through E, in classful network network addressing architecture. The class designations were based on the split of 32 bits required for an IP address, the first four of which indicated the address classe in binary code:

  • A=0
  • B=10
  • C=110
  • D=1110
  • E=1111

The classful network architecture was used from 1981 to 1993, when classless inter-domain routing (CIDR) was introduced. This new architecture’s goal was to decrease the rapid growth of routing tables on routers throughout the Internet and slow the inevitable depletion of IPv4 addresses.

Techopedia Explains Class C Network

Although the classful network and the class C network designation were discontinued, network administrators and IT personnel still occasionally make reference to them. Some hardware and software components may also reference them.

The classful network originally used a 32-bit IPv4 address, which only supported 254 independent networks. With a few large networks, such as Advanced Research Projects Agency Network (ARPANET) and the proliferations of local area networks in the early to mid-1980s, it soon became apparent that more addresses would be needed. This is why the classful network methodology was adopted, allowing the following number of networks for each of five classes:

  • A: 128 (27)
  • B: 16,384 (214)
  • C: 2,097,152 (221)
  • D is defined as multicast, while E was not defined and was kept for future use

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Margaret Rouse

Margaret is an award-winning technical writer and teacher known for her ability to explain complex technical subjects to a non-technical business audience. Over the past twenty years, her IT definitions have been published by Que in an encyclopedia of technology terms and cited in articles by the New York Times, Time Magazine, USA Today, ZDNet, PC Magazine, and Discovery Magazine. She joined Techopedia in 2011. Margaret's idea of a fun day is helping IT and business professionals learn to speak each other’s highly specialized languages.