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Subnets needed?

By JoeLZ ·
I'm new to networking. My predecessor recommended my company to break up our 192.168.x.x network into 3 subnets, 1 for the servers, 2nd for dept. A and 3rd for dept. B. We only have 40 users but are installing an VoIP system. Our vendor indicated there's no benefit to subnetting here since we have plenty of IPs. Other than the number of hosts, is there any benefit to subnetting for a small number of users?

Thanks in advance!

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by CG IT In reply to Subnets needed?

not really.

I could see someone trying to segment a group of computers from all others but subnetting is usually done to free up IP address. The the Class C 192.16.1/24 you've got 254 IP addresses of which you've only used 40. you've got 214 left unused.

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by JoeLZ In reply to

Thanks CG IT, I heard the same from other admins.

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by razz2 In reply to Subnets needed?

CG IT is correct. ip address' are divided into to parts. A network id and a host id. As an example:

ip address: 192.168.1.100
subnet mask: 255.255.0.0

In that example the network id is 192.168.0.0
The host id is the 1.100

The mask filters out the network so that tcp/ip can decide if the packets being sent are supposed to go to the local or a remote subnet. If the network id does not match the local machine network id then the data is sent to the default gateway (router). Two different subnets can not communicate with each other without routing.

This class B example leaves 65,534 hosts. Imagine a broadcast packet to that many hosts. Or, imagine a company with many locations. They could borrow bits from the host id octets to create a custom subnet mask thus creating multiple subnets from one larger one. It might provide for better traffic management or just better design.

With that said, with 40 hosts I see no reason for it. Putting your servers on their own subnet would also require you setup some routing. If this were my job I would not recomend it.

Here are some links for you:

http://www.tcpipguide.com/free/t_IPCustomSubnetMasks.htm

http://www.swcp.com/~jgentry/topo/subnet.htm

Good Luck,

razz

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by JoeLZ In reply to

Ok, there seems to be a concensus, I have run this by other and it seems this is not necessary at this time. Thanks for the quick responses razz2

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by JoeLZ In reply to Subnets needed?

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