Why and how to build data networks

Ruslan Rakhmetov, Security Vision

Constant data transfer from one place to another is the key to stability of people's lives and business functioning. With the help of a network you are reading this article, you can congratulate a person from another city or country on a holiday, and if you are in orbit inside a space station, you can contact your team and relatives. In this article we will talk about different approaches to creating Wide Area Networks ( WAN) and discuss the differences between such networks and Local Area Networks ( LAN).

To begin with, it is important to say that the main difference is the scale of the networks:

- A LAN is designed to connect devices within a single location and serves typically tens, hundreds, or sometimes thousands of devices. This could be a network of a smart kettle, an outlet, a TV or speaker with Alice, as well as other devices in your smart home. LAN technologies are often used to build connections in computer clubs (remember those?), university dormitories and sometimes even entire LCDs where there is a common local area network for file sharing. Of course, the individual company offices inside also ensure that their devices are linked into a single LAN.

- A WAN is already designed to connect many LANs and provide service to millions of devices. Such networks often cover large geographical distances and can connect computers and other devices that are thousands of kilometres apart. The global Internet is designed in this way.

Both types of networks allow the transmission of data from one point to another, but because of differences in scale and geography, they use different technologies and approaches to do so and have different properties, which are discussed below.

- Latency (signal delay) in LANs is less than in WANs.

Data transmission sometimes seems instantaneous, sometimes it takes forever. The greater the distances between metro stations, cities and countries, the longer it takes to get from one place to another - all logical not only for travelling, but also for data exchange on both types of networks. The speed of traffic and the delay between sending a signal and receiving a response sometimes determine not only the convenience of communication or the stability of an application, but also profit. So, for example, when trading on the stock exchange, receiving responses from traders a fraction of a second faster than competitors, you can build an entire business, as in the film ‘Operation Kolibri’ 2018.

- The cost of data transmission and infrastructure building for localised networks is also lower than for wide area networks.

This is due to the ease of maintenance and use of local equipment. For example, LAN networks are often budgeted on a CAPEX model, while for WANs of a particularly wide geography, OPEX costs (ISP fees and associated maintenance costs) are likely to be additionally applicable, in addition to significant investments in the equipment itself.

- Network security is organised differently: physically securing a LAN network within the premises is certainly easier than WAN cables that stretch across the country and are not monitored 24x7. Despite this, an attacker, when gaining access to one point in the local infrastructure, can connect to everything else fairly quickly. He can use the simple password from your home Wi-Fi router and then not only go online (to watch a YouTube video), but also change the router's settings, connect to unprotected smart home devices, enter a unified network with personal computers, etc.

Despite the scale of a LAN network and the apparent simplicity of its protection, failure to follow basic cyber hygiene rules can make a LAN less secure. WAN networks, on the other hand, allow you to organise security for web applications and protection against DDoS attacks, because filtering data on central corners around the world is more effective than on each site individually, as we have already discussed here and here.

- The proprietary nature and organisation of the two types of networks is also different. LANs are usually not just geographically confined to a single room or building, but are maintained by one person, while WANs usually require the involvement of not only a technical administrator, but also an architect, an analyst, a communications service provider and are generally more complex.

The proprietary nature of the two networks can be compared with operating systems for smartphones:

Apple offers the use of iPhones and independently maintains a single operating system used only on these devices. The result is a smooth, well-organised system operation that is impossible to apply to devices outside the Apple ecosystem. The high proprietary nature of the technology makes it easier to use, but more difficult to customise and modify.

On the other hand, there are Microsoft or Google vendors, whose operating systems are supported by almost all manufacturers, used on devices of various kinds, from smart watches and TVs to smartphones, ATMs and computers. It's easier to add custom functionality to these vendors' systems, and sometimes it's even possible to use open source code and create your own system. The result is greater flexibility at the expense of less proprietary features.

In this comparison, LANs are more like iOS and WANs are more like Android (not the most accurate comparison, but close enough): a single provider and simplicity on the one hand and adaptability and the ability to combine anything into a single network on the other.

- Technologies and organisation of communication for LAN-networks are faster and more reliable. These are usually Ethernet, Wi-Fi and gigabit switches. WANs often require the use of different technologies and protocols to enable long distance data transfer. This can include the use of the Internet, MPLS (MultiProtocol Label Switching), cellular networks and other technologies.

Compare these approaches to electromagnetic waves: a single radio or television tower can broadcast to an entire city and transmit music and video through walls, buildings and small barriers. Bluetooth technology also transmits data wirelessly, but works better and faster within a short distance.

LAN and WAN networks, of course, differ from each other in terms of data rate and signal delay, security and cost of use, but they are not competitors. Each network has its own challenges. The use of both technologies is usually possible in companies with several offices or to organise uninterrupted video communication over the Internet. LANs typically focus on services such as large file sharing, printing, videoconferencing and shared document storage in a single location, while WANs provide the ability to connect multiple LANs and scale services over long distances, including remote access, cloud computing, global Internet sharing and more