Networking Basics
Protocols
Protocols are methods for transmitting data between machines, and are necessary for the successful exchange of information. Many established protocols have been widely accepted, and build upon one another to form layers of information about the transmitted data. These layers allow the computer to use the data more efficiently.
| Layer | Example |
|---|---|
| Link Layer | Ethernet |
| Internet Layer | Internet Protocol (IP) |
| Transport Layer | Transmission Control Protocol (TCP) |
| Application Layer | HyperText Transfer Protocol (HTTP) |
Table 1: The four layers of the Internet stack and examples of protocols at each layer.
Figure 1: The data gets wrapped in multiple protocols.
Connecting to the Network
Each computer connecting to the network must be assigned a unique Internet Protocol (IP) Address. This allows other computers to know where a particular machine is located on the network and how to send information to that machine. The two types of IP addresses available are static and dynamic. Static IP addresses assign an unchanging, known address to the machine, and dynamic IP addresses are automatically assigned from a list of available addresses using Dynamic Host Configuration Protocol (DHCP).
Internet Protocol version 6 (IPv6) is the current standard protocol (June 2011) used to IP addresses. It uses a 128-bit address – the earlier protocol, IPv4, uses 32 bits. The new address space supports 2128 (about 3.4×1038) addresses, vs. the 232supported by IPv4.
Network Address Translation (NAT) allows all of the computers connected to a router to share a single, public IP address. It then assigns a private IP address to all connected computers that it translates to the public address when sending the traffic to the Internet. NAT also acts as a firewall, and is widely used in home networks and small businesses.
DNS (Domain Name System) allows you to use domain names instead of actual addresses to access a computer. The most common example of this is the address bar in your web browser. DNS is what allows you to access a page by typing “www.google.com” instead of the actual IP address for the Google search engine. DNS Servers keep track of the domain name and their associated IP addresses for ease of access. DNS can refer to Domain Name System or Domain Name Server.