subnetting

[omegasa]

Hi,

Suppose I have the net 10.100.0.0 with subnet mask 255.255.255.0. After subnetting , the first network is
10.0.1.0 I’m a little bit confused. How is possible(at first view) 10.0.1.0 to be “under” 10.100.0.0 ?

Thanks in advance

 

[CiscoGuy33]

omegasa,

If you have a network 10.100.0.0 with a subnet mask of 255.255.255.0 - the 255.255.255 says that you are using the 1st 3 octets for the network and subnets and the 0 says you are using the 4th octet for hosts.

10.100.0.0 is just 1 of many possible subnetworks on the 10.0.0.0 network as is 10.0.1.0, 10.100.100.0 ........

10.0.0.0 is a private network so what many companies do when using the 10.0.0.0 network the 2nd octet may denote a location or a building and the 3rd octet my denote a floor or department in that building such as on a college campus -
Poly Sci (1st floor)is 10.100.1.0
Poly Sci (2nd floor) is 10.100.2.0
Math is 10.110.1.0
Biology is 10.120.1.0
Biology (3rd floor) is 10.120.3.0

Hope this helps!

E.A. Broda
CCNA, CCDA, CCAI, Network +

 

[omegasa]

I mean at first view 10.130.0.0 could be part of 10.0.1.0 and not vice-versa.

Thanks

 

[CiscoGuy33]

omegasa,

With the private range of 10.0.0.0 it all comes down to how you structure your network.

10.130.0.0 and 10.0.1.0 are both just 2 of many subnets on the 10.0.0.0 network! 10.0.1.0 is not "THE NETWORK" 10.0.0.0 IS!!!

Not really sure what you are asking but you are looking at relationships between subnets - not sure WHY ????

Most CCNA questions will ask you if a host is on a certain subnet/network or if an IP is a network number, a host or a broadcast number.

omegasa, go to this website and you can download Chapter 3: IP Subnetting and Variable Length Subnet Masks (VLSMs)
FREE from the Sybex CCNA Study Guide (5th ed) by Todd L. - I think this is one of the BEST chapters ever written on subnetting

http://www.bookpool.com/sm/0782143911

Hope this helps!!


E.A. Broda
CCNA, CCDA, CCAI, Network +