• # Subnetting using binary method.

Hello everyone. I'm trying to prepare to Network+ exam watching a Net+ course right now.
As I can see you guys using this binary method to calculate Network ID, Broadcast address, first\last IP etc.
Could you help me with class B? I'm not sure how to act when I subnetting B or A classes.
For instance I'm looking at an example:
Find the subnet ID (network ID I presume)
I'm able to convert this into binary :
165.245.01001101.00001110
255.255.11110000.00000000
I assume we have default allocation which is /16 and after this I'm confused not sure what to do next,

P.s. a quick feedback would be nice if you add A or B example to your course. Thanks a lot.

• For instance I'm looking at an example:
Find the subnet ID (network ID I presume)
I'm able to convert this into binary :
165.245.01001101.00001110
255.255.11110000.00000000
I assume we have default allocation which is /16 and after this I'm confused not sure what to do next,

With this given information, you're trying to determine which class B subnet that the IP address belongs. I will begin the process so you can see if you can determine which one.

So a class B begins with 16 bit subnet mask. You've added an additional 4 bits to it from the HOST bits. These 4 bits now becomes your network IDs.

1st network

165.245.0000|0000.00001110 = 165.245.0.0
255.255.1111|0000.00000000 = 255.255.240.0

2nd network
165.245.0001|0000.00001110 = 165.245.16.0
255.255.1111|0000.00000000

3rd network
165.245.0010|0000.00001110 = 165.245.32.0
255.255.1111|0000.00000000

4th network
165.245.0011|0000.00001110 = 165.245.48.0
255.255.1111|0000.00000000

5th network
165.245.0100|0000.00001110 = 165.245.___.0
255.255.1111|0000.00000000

6th network
165.245.0101|000000001110 = 165.245.___.0
255.255.1111|0000.00000000

7th network
165.245.0110|0000.00001110 = 165.245.___.0
255.255.1111|0000.00000000

8th network
165.245.0111|0000.00001110 = 165.245.___.0
255.255.1111|0000.00000000

9th network
165.245.1000|0000.00001110 = 165.245.___.0
255.255.1111|0000.00000000

10th network
165.245.1001|0000.00001110 = 165.245.___.0
255.255.1111|0000.00000000

11th network
165.245.1010|0000.00001110 = 165.245.____.0
255.255.1111|0000.00000000

12th network
165.245.1011|0000.00001110 = 165.245.___.0
255.255.1111|0000.00000000

13th network
165.245.1100|0000.00001110 = 165.245.XXX.0
255.255.1111|0000.00000000

14th network
165.245.1101|0000.00001110 = 165.245.XXX.0
255.255.1111|0000.00000000

15th network
165.245.1110|0000.00001110 = 165.245.XXX.0
255.255.1111|0000.00000000

16th network
165.245.1111|0000.00001110 = 165.245.XXX.0
255.255.1111|0000.00000000

Examples of Class A and Class B, you may want to look into the Cisco CCNA show there is an example there. At the Network+ level, we're really introducing you to the concept and we must start and stay with Class C.

Cordially,
Ronnie Wong
Edutainer Manager, ITProTV

*if the post above has answered the question, please mark as solved.
**All "answers" and responses are offered "as is" and my opinion. There is no implied service, support, or guarantee by ITProTV.

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