Encyclopedia > Classful network

  Article Content

Classful network

Classful networking is the original method of determining whether an IP address belongs in the same IP network as another IP address.

It is also for establishing the host address size for any given IP address. The address mask, which is so commonly associated with an IP address today, was not required as the mask length was purely a function of the IP address. Any network device could inspect the first few bits of the 32 bit IP address to see which class it belonged to.

Class
start
end
first bits
Mask (in dotted decimal)
Class A
1.0.0.0
126.0.0.0
0
255.0.0.0
Class B
128.0.0.0
191.255.0.0
10
255.255.0.0
Class C
192.0.0.0
223.255.255.0
110
255.255.255.0
Class D (multicast)
224.0.0.0
239.255.255.255
1111
n/a
Class F (experimental)



n/a

The 127.0.0.0 network is reserved for loopback addresses.

Early allocations of IP addresses by IANA were in some cases not made very efficiently. This resulted with some organisations receiving class A networks which has contributed to the IP address shortage[?].



All Wikipedia text is available under the terms of the GNU Free Documentation License

 
  Search Encyclopedia

Search over one million articles, find something about almost anything!
 
 
  
  Featured Article
Brazil

... according to the principle of majority to serve eight-year terms; one-third elected after a four-year period, two-thirds elected after the next four-year period. Beside the ...

 
 
 
This page was created in 24.3 ms