Understanding Computer Systems: LANs and WANs

LAN stands for the acronym for local area network, and WAN stands for wide area network.

LANs and WANs are both computer networks made up of nodes and links. Both the LAN and WAN networks require two or more nodes to create a computer network.

LANs connect devices that are physically close to each other by using connectors like routers and switches. This network is useful for small geographic areas like a home or office to exchange data and communicate securely. LANs are faster and offer more control than WANs because they’re managed internally and cover less distance through Ethernet cables or wireless access points. These connections allow for fast communication between devices within a confined geographical area.

WANs connect devices across a larger geographic area. It covers beyond a single building or large campus to connect multiple locations spread across a specific geographic area or even the world. WANs are slower and have less direct control because they need third-party services and cover more ground. Establishments use WANs to facilitate digital interactions and data sharing between employees and customers in different regions or countries. WAN connections are normally virtual connections over the public internet. A variety of telecommunications links such as Leased lines, Multiprotocol label switching (MPLS), Virtual private network (VPN), and Cloud-based connections link together resources hosted in the cloud and are used to connect WAN devices over a larger geographical area.

A network node may be data communication equipment (DCE) or data terminal equipment (DTE). DCE includes things like modems, hubs, or switches, while DTE maybe something like two or more computers and printers. A link is the transmission media that connects two nodes. Wired connections use Ethernet cables made of coaxial, fiber-optic, or twisted-pair technology. On the other hand, wireless connections use radio waves, like 3G, 4G, or 5G technology, to connect nodes.

OSI layers:

OSI stands for Open Systems Inter-connection, where open stands to say non-proprietary. It is a 7-layer architecture with each layer having specific functionality to perform. All these 7 layers work collaboratively to transmit the data from one person to another across the globe. The OSI reference model was developed by ISO – ‘International Organization for Standardization ‘, in the year 1984.

LANs use data communication equipment (DCE) from OSI layers 1 and 2. Layer 1 devices, such as hubs and repeaters, physically transmit data over the network. For example, they may convert digital signals into analog signals for transmission over a physical medium. Layer 2 devices, such as switches and bridges, establish and maintain communication between devices on the same network segment.

WANs use DCE from OSI layers 1, 2, and 3.  Layer 3 devices route data between different network segments. To do this, they examine incoming data packets’ addresses and forward them to the appropriate destination networks. Examples include multi-layer switches, routers, and technology-specific devices such as frame-relay switches and asynchronous transfer mode (ATM).

Security:

Users of both LANs and WANs can secure their networks by using various methods such as VPNs, firewalls, encryption, and access control. Security measures prevent unauthorized access to the network and protect sensitive data during transmission. However, LANs are considered more secure than WANs because WANs are more susceptible to security threats due to their large scope and connection to the Internet, which is a major source of security threats.

Control Message Protocol (ICMP):

Both LANs and WANs use sets of rules called communication protocols, such as firewalls, encryption, and access control. These protocols manage data transmission between connected devices. The most common protocol is TCP/IP. Other protocols for different types of communication, like the User Datagram Protocol (UDP) and the Internet, also exist.

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