Duffers guide to Subnetting PLEASE!!!

[Guest_imported]

HELP!
Can anyone give a very basic analogy of subnetting...
just to clarify what this is on about...

http://www.tek-tips.com/gviewthread.cfm/lev2/3/lev3/19/pid/55/qid/5393

basically, if you are running a private network say on 192.168.*.* and a subnet of 255.255.255.0 for example,
if you start adding subnets to different parts of the LAN what are the benefits? Is it a traffic issue, security, or just administration benefits?

sorry for being thick...bit new to this!!!

 

[Zorlod]

The benifit of subnetting is to divide network traffic on larger networks. The only way for traffic to travel between the two subnets is through a router which has the subnets programed into its tables. That way only traffic specifically addressed to a computer in another subnet will go though. not just every broadcast packet that comes out.

 

[screaminniemann]

Excellent description Zorlod. I wish Microsoft help files
would learn how to explain the logic behind equipment instead of just saying "click here". Half the time their result doesn't match mine. Thanx

 

[webnetwiz]

You would use subnetting if you have single IP block, let's say your ISP gave you 167.10.24.0/24 (24-bit subnet mask, or 255.255.255.0). This will allow you to run 254 hosts. But for administrative or political reasons, you need to separate this into 2 networks, that's when subnetting comes in.

I recommend reading Interconnecting Cisco Network Devices, from Cisco Press, they have an excellent chapter on subnetting, and how to do a binary conversion in 8 steps, and you'll never use a calculator again.

 

[Guest_imported]

Nice one guys.... but just to query webnetwiz, if for arguments sake i am using an ISP assigned ip, of 167.10.24.0 with a 255.0 subnet, if i wanted to split up the network and use a new subnet, would it have to be ISP assigned again for it to still be routed to the web, or does the actual IP sort that regardless of subnet?