There are a few definitions of Wide Area Network and it is usually associated with a network that covers larger geographical locations and it could connect multiple LANs. It traverses commercial carriers and public networks. Modems, switches and routers are main components of WAN and we also need fiber or copper cables to connect with multiple servers in the area. In a WAN, it is important to have multiple types of equipments that work based on specific options. As an example, router is a typical hardware that we need in a WAN. Routers are needed to connect LANs with the rest of WANs, especially because we can handle the routing messages when needed. These routers work based on IP addresses or at layer 3. Switches are also needed to select paths or circuits for sending specific packets of data to the destination. They work based on MAC addresses, which are located at layer 2, to send data packages to the proper destinations. Modem is known as the modulator and demodulator device and it could allow computers to communicate with one another at layer 1.
It is clear that WANs work at layer 1, 2 and 3; depending on the type of equipments. Obviously, the physical layer is also important and it defines how functional, mechanical and electrical connections could work. In the data layer, encapsulation is an important factor, because it could wrap data packages using specific protocol headers. These headers are often used identifier to organize data transmission and ensure reliability. Regardless of the encapsulation method, we should make sure that it is compatible on both the sending and receiving sides. Packet and circuit switching methods are essential in any high capacity network. This should ensure that data can be transmitted across the whole network using proper packet switching. In this case, packet switching is somewhat less reliable than circuit switching, although it is more modern and more affordable. Routing protocol is needed to specify how routers could communicate with one another. In general, routers should have prior knowledge about the neighbouring areas, such as the network structure and topology.
Routing Information protocol or RIP is a common type of protocols used by internal networks. RIP can help us to adapt to changes dynamically. They can communicate information between network routers to reach specific distance. However, RIP is notorious for its somewhat lower reliable, which can render network non-functional. To improve reliability, it is important for routers to constantly inform one another about essential details, such as the latest routing table. In general, routing is a task to decide how data packages should be moved from one network to others. Paths that these packages need to traverse are also known as routes and they can be defined based on specific efficiency and effectiveness factors. All machines in WANs are identified by IP address, starting with common local addresses, specifically 192.168.xxx.xxx. There should be enough addresses to make sure that all machines can be properly identified.