WAN vs LAN: How do they differ?

This article is a comparison of WAN vs LAN, pointing out the key differences, limitations, and benefits of both taxonomies.

Computer networks were invented and have been around more than fifty years ago when the ARPANET (Advanced Research Projects Agency Network) was created and deployed. Ever since, computer networks have been growing in scale, size, and sophistication. Early networking infrastructures were destined to support data exchange between various computers, while contemporary networks accommodate richer forms of network traffic from a significantly wider array of terminal devices such as smartphones, peripheral equipment, and numerous types of IoT (Internet of Things) devices. 

Since the early days of networking, computer networks were classified on the basis of the scale at which they connect devices. The types included Wide Area Networks (WANs), Local Area Networks (LANs), Metropolitan Area Networks (MANs), and later Personal Area Networks (PANs) as well. 

These networks were used to establish a telecommunication link between different devices that were a part of it. Specifically, the distinction of networks in WAN vs LAN was one of the first and most popular taxonomies of computer networks. Despite the advent of novel types of networked computing paradigms (e.g., mobile computing, IoT computing, tactile internet), this taxonomy remains important and relevant.  

What is WAN (Wide Area Network)?

WANs cover large-scale geographic areas such as areas of regional, national or international scales. They comprise multiple networking devices and equipment, including 

(i) Edge devices like Digital Subscriber Lines (DSLs), routers, switches, modems; 

(ii) Connectivity and transmission media like optical fibers, wireless media, microwave, and satellite network connections; and 

(iii) Customer Premises Equipment (CPE) such as switches, routers, and other internetworking devices residing at the user’s side. 

A WAN can be connected to other types of networks (including LANs and MANs) to carry their internet connection traffic governed by a set of communication protocols, like Transmission Control Protocol/Internet Protocol (TCP/IP), across large geographic areas. WANs come with their own set of advantages and disadvantages, which modern enterprises must consider as part of their network deployment considerations.

Advantages

The main advantage of WANs networks lies in their ability to deliver a high-speed data-transfer rate while covering larger areas. A WAN is usually the sole option when it comes to interconnecting organizations on a national or international scale. The speeds can range between a few Mbps and Gbps depending on the communication type. 

Another advantage of WAN deployments is the centralization of data and services, which helps the internetworking of organizations that comprise numerous devices and data sources. 

Specifically, a WAN connection centralizes access to data from multiple sources, while at the same time facilitating the sharing of these data across many devices. For instance, a WAN facilitates global organizations to share data across different branch offices that reside in various countries and regions. In this context, corporate users can instantly access files and data from other offices and locations without making it available over the public internet. 

In several cases, WANs are used to enable access to cloud computing infrastructures from remote workstations, which add scalability, capacity, and Quality of Service (QoS) advantages to the ease of data sharing. Likewise, WANs are a very good choice when it comes to collecting, analyzing, and processing IoT traffic in the cloud. This is the reason why there are various IoT networking technologies that support the establishment and operation of WANs for IoT data.

WAN networks are in most cases back-bone networks i.e., they are destined to carry very large amounts of network traffic. Therefore, they are designed and deployed to provide very large capacities, which is one more advantage of WAN networks. 

Moreover, WAN services are usually provided in the scope of Service Level Agreements (SLAs) with a network provider, which is usually committed to offering significant uptime and reliability.

Disadvantages

The downside of WAN networks relates to their complexity and security. WANs cover large areas, which makes their setup more difficult and more expensive. For example, WANs cover areas without proper electricity supply, which leads to local availability problems. 

Moreover, they are heterogeneous and tend to combine multiple networking technologies across several integration points in different geographical areas. As such they have various vulnerability points, which makes them more susceptible to security attacks and increases the cost of cybersecurity. Another disadvantage of WANs relates to their maintenance. Certain parts of WANs reside in rural areas or even under the sea. This increases the complexity and challenges of their maintenance.

What is LAN (Local Area Network)?

Contrary to WANs, LANs are networks that span relatively small geographic areas like a corporate office, a single building, or a campus. LANs comprises various networking devices such as hubs, switches, and wireless access points. 

Based on these devices, different LAN configurations can be established, which offer a variety of performance, scalability, and cost-efficiency propositions. Likewise, there are many different LAN topologies such as bus, ring, and star topologies.  

The latter is supported by a wide array of LAN technologies such as Ethernet, Token Ring, and Fiber Distributed Data Interface (FDDI) based on fiber optic technology. There are also a rich set of wireless LAN standards, such as the standards of the IEEE 802.11 family (e.g., 802.11, 802.11a, 802.11b, 802.11g, 802.11n, 802.11p, 802.11ac, and 802.11ax). WiFi routers help in establishing a local network along with internet access.

From an operational perspective, two main types of LANs are distinguished: 

(i) Client/server LANs, which comprise one or more servers. Client computers connect to these servers to access files, data, and other resources; and 

(ii) Peer-to-peer LANs, where different peer nodes provide access to their resources (e.g., computing power, storage, files) without central coordination (e.g., the need for a server). Hence, client/server LANs and peer-to-peer lines differ in their configuration and administration.

Advantages

One of the main advantages of a LAN is the simplicity of its configuration and the ease of sharing resources. This is because LANs are typically small or medium networks that can be configured and managed in a wired configuration for devices having a LAN port with the help of ethernet cables or in a wireless configuration for devices having a WiFi antenna using a wireless router. 

Likewise, applications can be also shared to reduce licensing costs. In the scope of a LAN, sharing of data and computing resources is fast and effective, as the network covers a small area, yet provides high bandwidth. Many LAN networks are secure, notably the networks that cannot be accessed by users outside the LAN. This is not always the case with wireless LANs (e.g., WiFI networks) that can be accessed by external users. Nevertheless, even in the case of WiFi networks, access control provisions, VPNs (Virtual Private Networks) and firewalls can be put into effect.

Disadvantages

The main disadvantage of a LAN is its limited coverage, which is a drawback for certain long-distance applications. For instance, LANs cannot support networked applications that span areas larger than some tens of kilometers. 

Furthermore, depending on the technologies employed and used, setting up a LAN network can become expensive. Moreover, there is always a need for additional costs and human resources for administering the LAN. LAN costs increase further due to the need to maintain the network in the presence of multiple software installations, hardware failures, and physical medium problems. 

Also, despite the good security features of LANs, LANs remain sensitive to the spreading of malware and other viruses: Once a computer gets infected, other LAN devices can be put at risk as well. Note also that server crashes (e.g., hardware or software failures) can greatly affect the operation of the LAN, especially in the case of client/server LANs. The setups require proper planning for increasing their fault tolerance.

LANs and WANs in an IoT Context

Nowadays, Internet-connected devices such as sensors, smartphones, and connected appliances require routing through LAN. Accordingly, they leverage the services of a gateway device (e.g., of a residential gateway in the home environment) to connect to the internet via an Internet Service Provider (ISP) and ultimately to some WAN. 

Nevertheless, there are many IoT networks that connect devices directly to a WAN port. This is the case for applications that need to connect thousands of sensors and devices in very large geographical areas.  For example, large-scale precision farming applications need to collect and analyze data from sensors that span many tens of kilometers i.e., they need to connect to a WAN. Such applications are supported by modern Low Power Wide Area Network (LPWAN) technologies such as SigFox and LoRaWAN. The latter provides excellent support for wireless, bi-direction communications for IoT applications in large areas like smart cities, smart energy grids, and connected manufacturing plants. 

The majority of non-trivial IoT networks combine LANs and WANs. LANs support functionalities within smaller areas like an office, a building, a plant, or a warehouse. At the same time, WANs facilitate IoT devices to interact with other IoT resources residing in different cities, regions, or countries. LANs and WANs are also combined in the context of the cloud/edge computing paradigm, which is the most popular IoT architectural pattern as reflected in relevant standards-based IoT reference architectures like the Industrial Internet Consortium Reference Architecture (IIRA). Specifically: 

(i) LAN networks are used to support edge computing functions, which feature low latency and increased security; while 

(ii) WAN networks are used to support cloud computing functions, which provide capacity and larger scale coverage. 

In a cloud/edge paradigm, different LAN-based edge computing functions and devices are integrated into a WAN-based cloud to facilitate scalable analytics. Therefore, IoT LAN networks support local functions (e.g., real-time actuation and control close to the field), while IoT WAN networks support global functions (e.g., accurate optimizations based on big data analytics). Most importantly, network service providers and network operators offer novel services that boost the interplay between cloud/edge functions towards achieving the best possible balance of performance, latency, and scalability.

Overall, several decades following the introduction of the LAN and WAN networks, this coverage-based taxonomy remains important. Over the years, many different LAN and WAN technologies have been developed, which are provided at a variety of configurations and costs. In this context, modern organizations leverage both LANs and WANs to support their enterprise networking needs. In most cases, they also combine and integrate LANs and WANs in line with their performance, scalability, and Quality of Service (QoS) goals. This is also the case with the emerging IoT networks, which are increasingly deployed in line with the edge/cloud paradigm.