IP Addresses
Every device that communicates on a network, utilizing the TCP/IP protocol, is identified by a unique IP address. The IP address identifies a host’s location on the network, much like a street address identifies a house location. The IP address must be unique for the network that it is a member of. Just like a house address, the IP address must be unique and be created using a uniform format.
Each IP address defines the network ID and the host ID of the device. The network ID defines devices that are on the same physical network. All devices on the same physical network must have the same network ID, and this ID must be unique for the network that the device is a member of. The host ID defines the actual device on the physical network, and must be unique for the network ID the device is a member of.
Each IP address is 32 bits long and made up of four 8-bit fields, called octets. Each of the four octets is separated by a period (.). Each of the four octets represents a decimal number between 0 and 255. This format is called dotted decimal notation. The following is an example:
Each bit position of an octet has an assigned decimal value or number. If a bit is set to 0 (zero), the bit position value is 0 (zero). If a bit position is set to 1 (one), then the bit position is converted to the decimal value or number assigned to that position. All of the decimal values of the bit positions of an octet are added together to get it’s decimal value. The low-order bit of the octet represents a decimal value of 1 (one), while the high-order bit represents 128. The highest decimal value that an octet may represent is 255 – or all bit positions set to 1 (one). The following table illustrates the bit position values of an octet.
Given the example above, to find the decimal number associated with this octet, we would add all of the decimal values of the bit positions that have a binary value of 1 (one) together to come up with the octet’s decimal value. So we would add 1 + 2 + 128 together, which equals 131. So this octets value is a decimal dotted notation of 131.
Every device that communicates on a network, utilizing the TCP/IP protocol, is identified by a unique IP address. The IP address identifies a host’s location on the network, much like a street address identifies a house location. The IP address must be unique for the network that it is a member of. Just like a house address, the IP address must be unique and be created using a uniform format.
Each IP address defines the network ID and the host ID of the device. The network ID defines devices that are on the same physical network. All devices on the same physical network must have the same network ID, and this ID must be unique for the network that the device is a member of. The host ID defines the actual device on the physical network, and must be unique for the network ID the device is a member of.
Each IP address is 32 bits long and made up of four 8-bit fields, called octets. Each of the four octets is separated by a period (.). Each of the four octets represents a decimal number between 0 and 255. This format is called dotted decimal notation. The following is an example:
Each bit position of an octet has an assigned decimal value or number. If a bit is set to 0 (zero), the bit position value is 0 (zero). If a bit position is set to 1 (one), then the bit position is converted to the decimal value or number assigned to that position. All of the decimal values of the bit positions of an octet are added together to get it’s decimal value. The low-order bit of the octet represents a decimal value of 1 (one), while the high-order bit represents 128. The highest decimal value that an octet may represent is 255 – or all bit positions set to 1 (one). The following table illustrates the bit position values of an octet.
Given the example above, to find the decimal number associated with this octet, we would add all of the decimal values of the bit positions that have a binary value of 1 (one) together to come up with the octet’s decimal value. So we would add 1 + 2 + 128 together, which equals 131. So this octets value is a decimal dotted notation of 131.
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