Network Class

[Sarvesh A Dhuri]

Hi

Why Class A Network starts from 1 to 126
Class B Network starts from 128 to 191
Class C Network starts from 192 to 223
Class D Network 224 to 239
& Class E Network from 240 to 255

Thanks in advance

[Todd McDaniel_1]

I do know that the main thing that matters is what each Class will support, at least based on the subnet masking...

My guess is that it was alpha based...no rhyme or reason....

[Sundar_7 · Accepted solution]

It is the first octet.

A Class

0000 0000 to 1000 0000 == 1 to 127 â 127 cannot be used it is the loopback address and 0 canot be used.

B Class

1000 0000 to 1100 0000 == 128 to 191 â

C Class

1100 0000 to 1110 0000 = 192 to 223

D Class

1110 0000 to 1111 0000 = 224 t

[Shaikh Imran]

Hi,

http://www.ericsson.com/support/telecom/part-h/h-3-2.shtml

Regards,

[Muthukumar_5]

Hai,

There is a dafult formation allocated for every class. IPv4 address is divided as network-id and hostnumber.

class

class A 1 byte 3 byte
class B 2 byte 2 byte
class c 3 byte 1 byte
class d & 4 byte -----
class e



CLASS A - first byte
2 bit flag as 01
6 bit host id
00000001 to 01111110 = 1 to 127

We use 127 for loop back purpose.

Class B - first byte
10000000 to 1011111 = 128 to 191

Class C - first byte
11000000 to 1101111 = 192 to 223

class D - first byte
11100000 to 1110111 = 224 to 239

class E
11110000 to 1111111 = 240 to 255

I hope you asked this same at networking forum at http://forums1.itrc.hp.com/service/forums/questionanswer.do?threadId=625762 :)

In addition check this link,
http://computer.howstuffworks.com/question549.htm

Regards,
Muthukumar.

[Yogeeraj_1]

hi,

See:
http://www.ipcop.org/1.3.0/en/install/html/ip-addressing.html

and RFC1918 talk more about it's WHY.

hope this helps
regards
Yogeeraj

[Yogeeraj_1]

hi again,

See also the article at:http://www.pcplus.co.uk/tips/default.asp?articleid=30088&page=1&pagetypeid=4&subsectionid=390

You will observe that these ranges arenâ t arbitrary. For Class A, the first bit of the address is '0', giving a range of 1 to 127 ('0' is reserved). For Class B, the first two bits are '10'. For Class C, '110' and so on.

hope this clarifies everything.

regards
Yogee