How Do Computers Communicate with Each Other

For your computer to communicate with other computers it needs a network interface card connected to the appropriate Network medium. This creates the physical connection to the network. The computer must also be configured to use the protocols that match the protocols used on the network.

By default, new computers typically come with the network cards installed, the proper drivers installed, and the network card is configured to use the Dynamic Host Configuration Protocol (DHCP) to receive TCP/IP configuration information automatically. The following summarizes the configuration settings required to connect to a TCP/IP network. These values will need to be delivered to each host using DHCP, or configured manually for each network connection.

IP address

The IP address uniquely identifies every host on the network. An IP address is comprised of four numbers separated ny periods. Each number group is called an octet and each octet can range between O and 255. so an IP address might look like 172.193.1.12. For computers you need to identify the host address along with a subnet address. A subnet address is a segment of a network that has the same subnet or network address. All the devices on this subnet share the same subnet address even though they have different host addresses. Both pieces of this information are contained within the IP address

The IP address Identifies both the logical host and the logical network addresses.

  • Each host on the entire network must have a unique IP address.
  • Two devices on the same subnet must have IP addresses with the same network portion of the address.
  • Two devices on the same subnet must have unique host portions of the IP address.
  • Do not use the first or the last host address on a subnet address range.

Subnet mask

The subnet mask identifies which portion of the IP address is the network address, and which portion is the host address. Two devices on the same subnet must be configured with the same subnet mask.

The computer separates the subnet address from the host address using a special value called a subnet mask. The job of the subnet mask is to divide the address into it's two component. A subnet mask looks like this, 255.255.0.0, in this case any octet that has a value of 255 is part of the subnet address.So in this case You have a subnet address that occupies the left two octets. So the subnet address would be 172.193.0.0. With everything past the mask is set to 0 for the subnet address.

The host address is then anything to the right of the subnet mask.

Configuring the IP address and the subnet mask allows a computer to communicate with other devices on the same subnet. But if you stopped your configuration here the devices you would not be able to communicate with computers on other subnets or the Internet. in order to do this you must define a default gateway.

Default gateway

The default gateway identifies the router to which communications for remote networks are sent. The default gateway address is the IP address of the router interface on the same subnet as the local host. Without a default gateway set, most clients will be unable to communicate with hosts outside of the local subnet.

If you've connected your network to the Internet and configured each host with an IP address, subnet mask and a default gateway, then your computer can talk to other devices on the network. Remember computers use IP addresses to communicate with each other. if you stopped your configuration there you would have to remember every IP address for every computer on the Internet and every web site you wanted to visit.

DNS server

The DNS server address identifies the DNS server that is used to resolve host names to IP addresses.

A special server called DNS (Domain Name System) is configured with host name and IP address of many different computers. So if I wanted to visit www.pctecmech.com my computer would ask the DNS server for the IP address that matches the name I gave it. The DNS server would then reply with the IP address and the computer would then use the IP address to communicate directly with that computer.

Host name

One other configuration you should be aware of is the host name. This is the logical name for your computer. You can configure your computer with a logical name that other users can use to identify and connect to your computer. This is not a requirement for connecting to the Internet because devices on the Internet typically do not contact your computer directly.

Use the following tools to manage network connections and network configuration:

On Windows 2000/XP, use My Network Places to view computers and shared folders on the network, view and manage network connections, and set up a local area or wireless network. In Windows Vista/7, My Network Places has been renamed Network.

On Windows Vista/7, use the Network and Sharing Center to view connected networks, manage file and printer sharing, and connect to a network. The Network and Sharing Center is similar to My Network Places, but gives you a graphical view of your network and allows you to more easily complete common networking tasks.

To edit TCP/IP properties for a network connection, open the Network Connections folder using the following methods:

  • On the Start menu, right-click My Network Places (or Network) and select Properties.
  • In My Network Places, click the View network connections link.
  • In the Network and Sharing Center, click the Manage network connections link.
  • On Windows 2000/XP, browse the Control Panel to the Network Connections icon.

In the Network Connections folder, right-click the network connection and select Properties.
In the Network and Sharing Center, you can also click the View status link for a connection, then click the Properties button.