What is an IP address??

Every device connected to the public Internet is assigned a unique number known as an Internet Protocol (IP) address. IP addresses consist of four numbers separated by periods (also called a 'dotted-quad') and look something like 127.0.0.1.
Since these numbers are usually assigned to internet service providers within region-based blocks, an IP address can often be used to identify the region or country from which a computer is connecting to the Internet. An IP address can sometimes be used to show the user's general location.
Because the numbers may be tedious to deal with, an IP address may also be assigned to a Host name, which is sometimes easier to remember. Hostnames may be looked up to find IP addresses, and vice-versa. At one time ISPs issued one IP address to each user. These are called static IP addresses. Because there is a limited number of IP addresses and with increased usage of the internet ISPs now issue IP addresses in a dynamic fashion out of a pool of IP addresses (Using DHCP). These are referred to as dynamic IP addresses. This also limits the ability of the user to host websites, mail servers, ftp servers, etc. In addition to users connecting to the internet, with virtual hosting, a single machine can act like multiple machines (with multiple domain names and IP addresses).

Cable Colour Codes

These colour codes are offered as guidance in allocating circuits and investigating existing installations. Many installers abbreviate colours to their initial and last letters – Bk for Black, Bn for Brown. An alternative is to use the initial letter, but to avoid duplication, under this system Black is K, Brown is N and Grey is S (for Slate). BBC designed cables usually use Slate instead of Grey, but as the two colours are very similar, and are never both used in the same cable, they are effectively interchangeable. The BBC colour codes are explained in ED122 Guide to Wiring (stock code 0446493).

Where two colours are shown separated by a hyphen, the first colour is the primary colour, usually the base colour, with the second (and third where appropriate) applied as thin bands or stripes. Occasionally cables are manufactured with less of the primary colour showing than the secondary colour (sometimes within the same cable) but this should not lead to confusion. In the CW1308 standard the primary/secondary colours are rigidly defined, and the primary colour (shown in capitals) is always the base colour.

Multipair cables have repeated solid colours as primaries, and the pair number is identified by the colour of the other half of the twisted pair – care should be taken when preparing these cables to ensure the correct pairing is maintained.

Crossover Cable
Sometimes you will use crossover cable, it's usually used to connect same type of devices. A crossover cable can be used to:
1) Connect 2 computers directly.

2) Connect a router's LAN port to a switch/hub's normal port. (normally used for expanding network)
3) Connect 2 switches/hubs by using normal port in both switches/hubs.

In you need to check how crossover cable looks like, both side (side A and side B) of cable have wire arrangement with following different color .

Straight Cable
You usually use straight cable to connect different type of devices. This type of cable will be used most of the time and can be used to:
1) Connect a computer to a switch/hub's normal port. 2) Connect a computer to a cable/DSL modem's LAN port. 3) Connect a router's WAN port to a cable/DSL modem's LAN port. 4) Connect a router's LAN port to a switch/hub's uplink port. (normally used for expanding network) 5) Connect 2 switches/hubs with one of the switch/hub using an uplink port and the other one using normal port.

If you need to check how straight cable looks like, it's easy. Both side (side A and side B) of cable have wire arrangement with same color.