Difference between revisions of "Introduction To Networking"
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Revision as of 12:15, 28 June 2009
Contents
The IP Address
Introduction
An IP address is a 32-bit binary number assigned to you computer on a network. For readability, the 32-bit binary IP address is usually separated by dots into four parts and each part is represented by a single decimal value. Each decimal value van range from 0 to 255, but the first number cannot be 0. In addition, all four numbers cannot be 0 (0.0.0.0) or 255 (255.255.255.255).
Dotted Decimal Notation
An IP address is actually a 32-bit long binary number. Because binary numbers are difficult to read IP addresses are usually displayed in dotted decimal notation rather than in binary. Dotted decimal notation breaks the 32-bit binary number up into 4 decimal numbers and then separates them with by three dots.
The Subnet Mask
Introduction
The subnet mask is a 32-bit number that is assigned to each computer to divide the 32-bit IP address into its network ID and host ID. This makes TCP/IP routable.
Why a subnet mask is required
When a computer delivers an IP packet, it uses the subnet mask to validate whether the destination is on the same network or on the remote network. If the destination is on the same network, the packet can be delivered by the computer. If the destination is on the different network, the computer must send the packet to a router for delivery.
Valid subnet mask
In a simple network, a subnet mask is composed of only 255s and 0s. Other values are not used. In addition, 255s appear at the beginning of the subnet mask and 0s appear at the end. In a valid subnet mask, 0s cannot be interspersed with 255s.
The Default Gateway
Introduction
The default gateway is the IP address of the router that will route remote traffic from the computer’s local network to remote networks. Typically, the default gateway is the address of the router that is connected to the Internet. A computer does not need to have a default gateway address if the computer does not need to communicate with computers outside its local network. In simpler terms, if you are trying to access resources on a computer and that computer is not on your immediate local network, your traffic will be sent to the default gateway address to see if it can be routed to the correct location.
