Re: Reserved addresses in subnet & Number of subnets

["Followup-To:" header set to comp.os.linux.networking.]
On 2010-01-11, karthikbalaguru <> wrote:
> Hi,
> In Class B Subnetting,
> 1. Consider that the subnet mask is 255.255.192.0
> then, the number of hosts is 16382. The number of
> subnets is 2.

??? There can be almost any number of subnets, as I understand it.
Subnets are not limited to groups of 256 addresses.

> 2. Similarly for the subnet mask of 255.255.224.0,
> the number of hosts is 8190. The number of
> subnets is 6.
>
> I understand that the reasons for 16382 and
> 8190 is that the first(all zeros) and the last
> addresses(all ones) have been reserved in
> every subnet due to historical reasons.
> Can you lemme know the historical reason ?
> I searched the internet, but did not find info
> except for some links mentioning the term
> 'historical reasons'.

broadcast

>
> Further, shouldn't the number of subnets be
> 4 for the first scenario and 8 for the second
> scenario ? Any specific reasons for not using
> subnet-zero(all-zeros subnet) and
> all-ones-subnet ?
>
> Thx in advans,
> Karthik Balaguru