[Techtalk] Networking tangent: subnets and netmasks

[Michelle Murrain]

At 3:34 AM -0400 4/16/03, Mary wrote:
<snip>

>The internal network is 10.0.0.224/29 (network 10.0.0.224, netmask
>255.255.255.248, broadcast 10.0.0.231).
>
>The external network is 10.0.0.188/30 (network 10.0.0.188, netmask
>255.255.255.252, broadcast 10.0.0.191).

<snip>

Reading Mary's query (which I have not a clue how to help) reminded 
me that I there is one major piece of TCP/IP that I just don't 
*grok*, although I can muddle through it if I need to: how to talk 
about subnets in that 10.0.0.224/29 nomenclature - how that 
corresponds to a block of IP addresses, and how that connects to the 
netmask and broadcast addresses.

Example. Lets say (I'm also going to use the 10.0.0.0 examples) I own 
a block of IP addresses from 10.0.0.32 through 10.0.0.63. That's 32 
addresses. Now the Network ID (what does that mean?) is .32, and the 
broadcast is .63 (this is what I am told.) My netmask, which I've 
also been told, is 255.255.255.224

So can someone translate how to describe this? It's a 10.0.0.32/what? 
Is the broadcast address always that last address? And why can't you 
ever use the .32 and .63 addresses for anything? And why is it a 
255.255.255.224 netmask (why is this 224 and not 223, which is 
255-32?)

Thanks!!
-- 
.Michelle

--------------------------
Michelle Murrain, Technology Consulting
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