I am having a problem understanding some subnetting concepts.
Say your company has leased the network 138.16.0.0/21. You want to subdivide this network
into 10 evenly sized subnets. This would require extending the mask 4 bit places for a /25 or 255.255.255.128 subnetmask giving you 16 subnets. This would leave 7 bits to assigh to hosts. 2^7 = 128 - 2 for network and broadcast addresses gives 126. 126hots * 7subnets = 882total clients.
Is my logic sound in coming to these conclusions? How would the networks be divided up? I would guess like this:
138.16.0.0 - 138.16.0.127 /25
138.16.2.128 - 138.16.2.255 /25
138.16.3.0 - 138.16.3.127 /25
138.16.4.128 - 138.16.4.255 /25
ect...
Ip addressing was the reason I failed the 291 the first time (got a 676

) and I still don't feel like I have the knoledge to pass.
I would greatly apreciate any attempt to enlighten me here.