0xxxxxxx Class A Decimal range: 0 - 127
10xxxxxx Class B Decimal range: 128 - 191
110xxxxx Class C Decimal range: 192 - 223
1110xxxx Class D Decimal range: 224 - 239
11110xxx Class E Decimal range: 240 - 255
Notice that the position of the "zero" bit keeps walking to the right as you go down the classes. Of course, this is only important in the classroom and for Cisco exams since in the "real world" classful addressing is a thing of the past! And as Brian stated, the mask has nothing to do with the class except in the context of the "default mask" which in classful addressing identifies the network portion of the address in an un-subnetted network.
Perhaps someday, Cisco will let us teach VLSM in the CCNA classes. :)
Tom Lisa, Instructor
Cisco Networking Academy
Community College of Southern Nevada
Brian wrote:
On Fri, 6 Oct 2000, Oscar Rau wrote:**NOTE: New CCNA/CCDA List has been formed. For more information go to http://www.groupstudy.com/list/Associates.html _________________________________ UPDATED Posting Guidelines: http://www.groupstudy.com/list/guide.html FAQ, list archives, and subscription info: http://www.groupstudy.com Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]> I am trying to determine the IP addresses assigned by a local ISP.
> The address pool comes from a Class A network with a 27 bit subnet mask.
>
> Is it subnet mask used only to determine the number of IP addresses in a subnet,
> regardless of the network class?subnet mask has nothing to do with determining the "class" of a
network. The first 3 bits of the address will tell you the class:000 Class A
100 Class B
110 Class C
111 Class DBrian
> --
>
> Oscar Rau
> [EMAIL PROTECTED]
>
> **NOTE: New CCNA/CCDA List has been formed. For more information go to
> http://www.groupstudy.com/list/Associates.html
> _________________________________
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>-----------------------------------------------
Brian Feeny, CCNP, CCDP [EMAIL PROTECTED]
Network Administrator
ShreveNet Inc. (ASN 11881)**NOTE: New CCNA/CCDA List has been formed. For more information go to
http://www.groupstudy.com/list/Associates.html
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