Subnetting A distributed networks savior By: Mike Guantonio
What are public and private Addresses? • Public addresses are addresses of the outside world • Given to us by the ISP • Private addresses are addresses inside the network that are not seen by the outside world.
When do we use Public Addresses • To set up a link to the outside world. • To set up routers in different parts of a work area.
Why do we need Sub-networks • Running out of IP addresses • Waste of IP addresses • Private numbers that can be used in any organization
Why do we subnet? • With private networks we can assign a block of addresses to various groups • Finance • Marketing • Help Desk • Development • This becomes more apparent with the introduction of VLans
What is the advantage of sub-netting? • We subnet large vs. small networks • A subnet breaks a network into smaller more manageable pieces • Much like how the phone company breaks down the telephone numbers with area codes.
Can different subnets “talk” to each other? • No • But with the help of switches and/or routers its possible • Nodes in the same subnet can communicate independently without any extra protocols needed.
Classes of Networks • Class A – N.H.H.H • Class B – N.N.H.H • Class C – N.N.N.H
Class Ranges • Class A – Range10.0.0.0 – 10.255.255.255 • Class B – Range 172.16.00 –172.31.255.255 • Class C – 192.168.0.0 – 192.168.255.255
What do home routers do? • Most routers will dish out an address of 192.168.1.(2-255) • This is not the address that other computers see • The reason for this is so that multiple computers can connect to the network without needing various IP’s • This is called NAT or PAT depending on the protocol.
Works Cited • Chapman, Bill, and Allan Johnson, Rick Graziani, Elaine Horn, Andrew Large, Antoon W. Rufi. CCNA 1 and 2 Companion Guide. 3rd . Indianapolis, Indiana: Cisco Press, 2005.