Subnetting A distributed networks savior By Mike Guantonio

Subnetting A distributed networks savior By: Mike Guantonio

What are public and private Addresses? l Public addresses are addresses of the outside world § l 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 l l 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 l l l Running out of IP addresses Waste of IP addresses Private numbers that can be used in any organization

Why do we subnet? l With private networks we can assign a block of addresses to various groups l l l Finance Marketing Help Desk Development This becomes more apparent with the introduction of VLans

What is the advantage of subnetting? l l l 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? l l l 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 l l l Class A – N. H. H. H Class B – N. N. H. H Class C – N. N. N. H

Class Ranges l Class A – Range 10. 0 – 10. 255 l Class B – Range 172. 16. 00 – 172. 31. 255 l Class C – 192. 168. 0. 0 – 192. 168. 255

How to subnet

What do home routers do? l l 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 l Chapman, Bill, and Allan Johnson, Rick Graziani, Elaine Horn, Andrew Large, Antoon W. Rufi. CCNA 1 and 2 Companion Guide. 3 rd. Indianapolis, Indiana: Cisco Press, 2005.