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Webcast-Catalyst9k
New Member

Network address

What will be its network address:

10.144.33.254/23

6 REPLIES
Cisco Employee

Re: Network address

The network address would be 10.0.0.0/8 if you take in consideration the classful model. The subnet address would be 10.144.32.0/23.

Hope this helps,

Harold Ritter
Sr. Technical Leader
CCIE 4168 (R&S, SP)
harold@cisco.com
México móvil: +52 1 55 8312 4915
Cisco México
Paseo de la Reforma 222
Piso 19
Cuauhtémoc, Juárez
Ciudad de México, 06600
México
New Member

Re: Network address

I was basically calculating it wrongly.Now i have found it.

Thanks a lot.

New Member

Re: Network address

Hi,

but how did you come to this info? can you show the formula on how you solve this?

I am new to this and I want to learn, so excuse my ignorance

thanks

Cisco Employee

Re: Network address

To obtain the subnet number, you need to consider only the bits dictated by the subnet mask from the IP address as follow:

10.144.33.254/23 (IP address and subnet mask)

0000 1010.1001 0000.0010 0001.1111 1110 (IP address)

1111 1111.1111 1111.1111 1110.0000 0000 (subnet mask)

0000 1010.1001 0000.0010 0000.0000 0000 (resulting subnet number in binary)

10.144.32.0 (resulting subnet number in decimal)

Hope this helps,

Harold Ritter
Sr. Technical Leader
CCIE 4168 (R&S, SP)
harold@cisco.com
México móvil: +52 1 55 8312 4915
Cisco México
Paseo de la Reforma 222
Piso 19
Cuauhtémoc, Juárez
Ciudad de México, 06600
México
New Member

Re: Network address

"To obtain the subnet number, you need to consider only the bits dictated by the subnet mask from the IP address as follow: "

That's exactly my problem. When given only 10.144.33.254/23, I don't know how to read this. So far I know 10.144.33.254 is the IP address, but the slash (/) throws me off... and the 23, I don't remember how to use it

How do you know 1111 1111.1111 1111.1111 1110.0000 0000 (255.255.254.0) is the subnet mask?

Purple

Re: Network address

Hi,

The number after the slash signifies the length of the mask. To convert this number to a subnet mask, simply write down that number of 1s, followed by a number of zeros until you have 32 digits in total. For the /23, that gives you:

1111 1111.1111 1111.1111 1110.0000 0000

Note that there are 23 ones followed by 9 zeros.

If you now convert each of the 8-bit blocks into decimal, you get 255.255.254.0

Hope that helps - pls rate the post if it does.

Paresh

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