Addressing and protocols
Any form of communication requires rules. These determine how the communication is actually made and manage key factors like transmission speed, error checking and methods of addressing, for example, how to locate another node on the network. Rules that govern communication are known as protocolA set of rules for how messages are turned into data packets and sent across networks.. Many types of protocol exist, but the ones that govern addressing are:
- IPInternet Protocol - A set of rules for communicating over the internet. IP can also stand for intellectual property. addressing
- MAC addressMedia access control - each unique piece of hardware on a network has a MAC address. addressing
IP Addressing
When connected to a networkA group of interconnected computers/devices. each device is given a unique IP addressA unique address for each computer device on a network.. This address consists of four sets of up to three digits, each with a maximum value of 255, which are separated by dots. An example is:
192.168.0.254
When a nodeAny device connected to a network. wants to send a message to another node, it uses the recipient node's address as the destination. A switchA device for connecting computers and other network capable devices together to form a network. on the network knows where the node with this address is and routes the message to it accordingly.
IP addresses can be:
- static
- dynamic
A node given a static address always keeps the same address. A node given a dynamic address has a different address assigned to it each time it connects to the network. This address is given using the dynamic host configuration protocol - DHCP.
Static addressing makes it easy for network managers to know which device is which on a network. However, dynamic addressing allows more devices to connect than there are available addresses. When a device disconnects from the network, its address is freed up for another device to use. When the first device reconnects, it is assigned any free address.
This method of addressing using four sets of digits is called IPv4. When IPv4 was devised, the range of addresses it allowed was deemed to be enough. However, the huge increase in internet-enabled devices has seen IPv4 run out of addresses. A new version, IPv6, which includes six sets of three digits, has been introduced, greatly increasing the number of possible addresses to trillions.
MAC addressing
A MAC address is a unique serial number assigned to each network interface card/controllerA circuit board that is installed in a computer so it can be connected to a network.. This allows a network to uniquely identify any device, even when a dynamic IP address is assigned using DHCP, each time the device connects to a network. The device’s IP address changes depending on the network and the MAC address is unique to the device.
A MAC address consists of a string of hexadecimalA number system using 16 symbols from 0-9 and A-F, also known as base 16 and hex. numbers. An example is:
1A:5B:6H:98:78:35
The MAC address is assigned by the NIC’s manufacturer and cannot be easily changed, so is referred to as a physical address. If a device has more than one NIC, for example a wired NIC and a wireless NIC, each NIC will have its own MAC address.
Other protocols
Many other protocols exist. Some of the more common protocols are:
- TCP/IP - Transmission Control Protocol/Internet Protocol - enables communication over the internet.
- HTTP and HTTPS - Hypertext Transfer Protocol - governs communication between a webserver and a client. HTTPS (secure) includes secure encryption to allow transactions to be made over the internet.
- FTP - File Transfer Protocol - governs the transmission of files across a network and the internet.
- UDP - User Datagram Protocol - similar to TCP, but because messages are sent instead of packets -chunks - it is often faster, allowing for gaming or video calls over the internet.
- SMTP - Simple Mail Transfer Protocol - governs the sending of emails over a network to a mail server.
- IMAP - Internet Message Access Protocol - governs retrieving emails from email servers.