On Sun, Jun 04, 2023 at 05:08:13PM -0500, o1bigtenor via Dng wrote:
> Greetings
>
> This group has so far shown a very large AND a very deep knowledge
> base in most anything I've ever thought connected to computers and
> computing.
>
> I'm trying to educated myself on networking and am finding, so far at
> least, that this is considered specialist only country. So when I
> start asking questions I get ignored because my questions are too
> basic (so they're considered boring) yet I can't find answers.
>
> I'll start with one question I'm grappling with at moment.
>
> Working on developing a networking system where there are a very large
> number of sensors/inputs.
> Trial version will have some at least 4 if not six such for one
> 'stall'. That's to make sure I can do what it is that I want to do.
> Version 1 would have 12 'stalls' so that at least 50 odd sensors/systems.
> (looking at having other functions so I'm loathe to think a limit of
> 'only' a couple hundred information points - - - that's for version
> 1(!!).)
> Version 2 could have anywhere from 50 odd to almost 200 discrete
> 'stalls' - - - this is not a this year project but, hopefully, not too
> far away.
> (This would mean that 1500 to 2000 sensor/system points is not too far
> into the future.)
>
> So I've been thinking of using a 172.16.x.x network rather than a
> 192.168.x.x as it would seem to me that I can easily put over 300
> sensors/systems on a 172.16.x.x system and I would need to be using
> some kind of system of cascading routers to use a 192.168.x.x .
>
> There is a change in ISP coming and I'm working on setting up a
> opnsense router/firewall - - - at present I'm on fixed wireless (quite
> pathetic internet service actually and far far too expensive for what
> I get!!) but that change is still some time away - - - at least a few
> weeks and maybe even a few months.
>
> Should I switch my present router from 192.168.1.1 to my chosen
> 172.16.x.x (I'm running on dd-wrt)?

It's really the netmask, or number of fixed bits, that determines the
span of IP addresses you have on a network. An IP address is 32 bits,
and the prevailing convention is to have the higher order bits fixed,
so as to form an enmeration space of the the lower order bits for
enumerating the hosts. (And by convention the highest and lowest
numbers in a space are "reserverd" to be "broadcast address" and
"network address" respectively).

By convention home routers use a 24 bit netmask by default, but most
routers have a programmable netmask and it's your choice what to use.

By agreement the whole 192.168.0.0/16 is considered a "private IP
space" that is not supposed to be routed on internet.

Thus, you may well keep 192.168.1.1 as router address, but change its
/24 (or 255.255.255.0) to eg. /20 (or 255.255.120.0) to give yourself
16 time more addresses on your network (i.e 4094 hosts + broadcast +
network).

If you go for 172.16.x.x you probably mean 172.16.x.x/12 (or netmask
255.120.0.0).. i.e. IP addresses that are all same in the 12 highest
bits, and allowing for 20 bits to host enumeration (plus "broadcast"
and "network").

That IP space is similar to 192.168.0.0/16 in being an agreed
"private" address space, although 16 times larger address space.

Those address space agreements are handled globally by IETF
(https://www.ietf.org/). Conventions are what they are and they show
up in various ways in user interfaces and programs.

Ralph.

>
> (Any suggestions for how to learn more about networking without buying
> hugely pricey Cisco courses?)
>
> TIA
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