What is group of connected computers that allow each other to make resources available to other computers?

A Local Area Network (LAN) is a group of computers or other devices interconnected within a single, limited area, typically via Ethernet or Wi-Fi.

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FAQs

What is a Local Area Network?

A LAN is a computer network that consists of access points, cables, routers, and switches that enable devices to connect to web servers and internal servers within a single building, campus, or home network, and to other LANs via Wide Area Networks (WAN) or Metropolitan Area Network (MAN). Devices on a LAN, typically personal computers and workstations, can share files and be accessed by each other over a single Internet connection.

A router assigns IP addresses to each device on the network and facilitates a shared Internet connection between all the connected devices. A network switch connects to the router and facilitates communication between connected devices, but does not handle Local Area Network IP configuration or sharing Internet connections. Switches are ideal tools for increasing the number of LAN ports available on the network.

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What are the Basic Layouts of Local Area Networks

The Local Area Network layout, also known as Local Area Network topology, describes the physical and logical manner in which devices and network segments are interconnected. LANs are categorized by the physical signal transmission medium or the logical manner in which data travels through the network between devices, independent of the physical connection.

LANs generally consist of cables and switches, which can be connected to a router, cable modem, or ADSL modem for Internet access. LANs can also include such network devices as firewalls, load balancers, and network intrusion detection.

Logical network topology examples include twisted pair Ethernet, which is categorized as a logical bus topology, and token ring, which is categorized as a logical ring topology. Physical network topology examples include star, mesh, tree, ring, point-to-point, circular, hybrid, and bus topology networks, each consisting of different configurations of nodes and links.

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How Does Local Area Network Work

The function of Local Area Networks is to link computers together and provide shared access to printers, files, and other services. Local area network architecture is categorized as either peer-to-peer or client-server. On a client-server local area network, multiple client-devices are connected to a central server, in which application access, device access, file storage, and network traffic are managed.

Applications running on the Local Area Network server provide services such as database access, document sharing, email, and printing. Devices on a peer-to-peer local area network share data directly to a switch or router without the use of a central server.

LANs can interconnect with other LANs via leased lines and services, or across the Internet using virtual, private network technologies. This system of connected LANs is classified as a Wide Local Area Network or a metropolitan area network. Local Area and Wide Area Networks differ in their range. An Emulated Local Area Network enables routing and data bridging an Asynchronous Transfer Mode (ATM) network, which facilitates the exchange of Ethernet and token ring network data.

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How to Design a Local Area Network

The first step in Local Area Network design is determining network needs. Before building a Local Area Network, identify the number of devices, which determines the number of ports required. A switch can extend the number of ports as the number of devices increases.

In order to connect devices wirelessly, a router is required to broadcast a wireless LAN. A router is also required to establish an internet connection for devices on the network. The distance between hardware devices should be measured in order to determine the length of cables required. Switches can connect cables for very long distances.

The setup simply requires connecting the router to a power source, connecting the modem to the router, connecting the switch to the router (if using), and connecting the devices to the open LAN ports on the router via Ethernet. Next, set up one computer as a Dynamic Host Configuration Protocol server by installing a third-party utility. This will enable all of the connected computers to easily obtain IP addresses. Turn on “Network Discovery” and “File and Printer Sharing” capabilities.

For wireless Local Area Network Installation, start by connecting the computer into one of the router's LAN ports via Ethernet. Enter the router's IP address into any Web Browser and log in with the network administrator account when prompted for a username and password. Open the “Wireless” section in the router settings and change the name of the network in the “SSID” field.

Enable “WPA-2 Personal” as the security or authentication option. Create a password under “"Pre-Shared Key," ensure that the wireless network is “enabled,” save changes, restart the router, and connect wireless devices to the wireless network, which should appear on the available network list of devices within range.

Characteristics of wireless Local Area Network include: high capacity load balancing, scalability, network management system, role-based access control, indoor and outdoor coverage options, performance measuring abilities, mobile device management, web content and application filtering, roaming, redundancy, wireless Local Area Network Application prioritization, network switching, and network firewalls.

A common Local Area Network issue is a disabled Local Area Network adapter or adapter error, which can be caused by faulty network adapter settings or by VPN software. Typical solutions include: updating the network adapter driver, resetting the network connection, and checking WLAN AutoConfig dependency services.

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How to Secure a Local Area Network

The majority of Local Area Network problems and solutions are concerned with the matter of security. There are a variety of strategies for designing a secure Local Area Network. A common approach is to install a firewall behind a single access point, such as a wireless router. Another valuable measure is to use security protocols such as WPA (Wi-Fi Protected Access) or WPA2 for password encryption on incoming Internet traffic.

Implementing specialized authentication policies enables network administrators to inspect and filter network traffic in order to prevent unauthorized access. Specific access points can be secured with the use of technologies such as VPNs. Internal Local Area Network security can be managed by installing antivirus or anti-malware software.

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Virtual Local Area Network Definition

A Virtual Local Area Network (VLAN) is a logical grouping of devices that can assemble together collections of devices on separate physical LANs, and is configured to communicate as if the devices were attached to the same wire. This enables network administrators to easily configure a single switched network to match the security and functional requirements of their systems without requiring any additional cables or significant changes to the current network infrastructure. VLANs are categorized as Protocol VLAN, Static VLAN, or Dynamic VLAN.

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Importance of Local Area Network in an Organization

There are several advantages of Local Area Networks in business:

Reduced Costs: LANs present a significant reduction in Local Area Network hardware costs and efficient resource pooling.
Increased Storage Capacity: By pooling all data into a central data storage server, the number of storage servers required is decreased and the efficiency of operations is increased.
Optimized Flexibility: Data can be accessed by any device from anywhere via Internet connection.‍
Streamlined Communication: Files and messages can be transferred in real time and accessed easily from anywhere on any device.

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Does HEAVY.AI Offer a Local Area Network Solution?

Real-time monitoring of network activity is essential to the security of a network. When linked together, LANs create Wide Area Networks and Metropolitan Area Networks, which are sometimes inundated with data sets that are too massive for the capabilities of a traditional analytics platform. With HEAVY.AI, telecommunications network operators and data scientists can monitor, analyze, and visualize billions of rows of data in real-time to diagnose and mitigate issues, optimize performance, improve the customer experience, and maintain the network’s high standards of reliability.

In this introduction to networking, learn how computer networks work, the architecture used to design networks, and how to keep them secure.

A computer network comprises two or more computers that are connected—either by cables (wired) or WiFi (wireless)—with the purpose of transmitting, exchanging, or sharing data and resources. You build a computer network using hardware (e.g., routers, switches, access points, and cables) and software (e.g., operating systems or business applications).

Geographic location often defines a computer network. For example, a LAN (local area network) connects computers in a defined physical space, like an office building, whereas a WAN (wide area network) can connect computers across continents. The internet is the largest example of a WAN, connecting billions of computers worldwide.

You can further define a computer network by the protocols it uses to communicate, the physical arrangement of its components, how it controls traffic, and its purpose.

Computer networks enable communication for every business, entertainment, and research purpose. The internet, online search, email, audio and video sharing, online commerce, live-streaming, and social networks all exist because of computer networks.

Computer network types

As networking needs evolved, so did the computer network types that serve those needs. Here are the most common and widely used computer network types:

LAN (local area network): A LAN connects computers over a relatively short distance, allowing them to share data, files, and resources. For example, a LAN may connect all the computers in an office building, school, or hospital. Typically, LANs are privately owned and managed.
WLAN (wireless local area network): A WLAN is just like a LAN but connections between devices on the network are made wirelessly.
WAN (wide area network): As the name implies, a WAN connects computers over a wide area, such as from region to region or even continent to continent. The internet is the largest WAN, connecting billions of computers worldwide. You will typically see collective or distributed ownership models for WAN management.
MAN (metropolitan area network): MANs are typically larger than LANs but smaller than WANs. Cities and government entities typically own and manage MANs.
PAN (personal area network): A PAN serves one person. For example, if you have an iPhone and a Mac, it’s very likely you’ve set up a PAN that shares and syncs content—text messages, emails, photos, and more—across both devices.
SAN (storage area network): A SAN is a specialized network that provides access to block-level storage—shared network or cloud storage that, to the user, looks and works like a storage drive that’s physically attached to a computer. (For more information on how a SAN works with block storage, see Block Storage: A Complete Guide.)
CAN (campus area network): A CAN is also known as a corporate area network. A CAN is larger than a LAN but smaller than a WAN. CANs serve sites such as colleges, universities, and business campuses.
VPN (virtual private network): A VPN is a secure, point-to-point connection between two network end points (see ‘Nodes’ below). A VPN establishes an encrypted channel that keeps a user’s identity and access credentials, as well as any data transferred, inaccessible to hackers.

Important terms and concepts

The following are some common terms to know when discussing computer networking:

IP address: An IP address is a unique number assigned to every device connected to a network that uses the Internet Protocol for communication. Each IP address identifies the device’s host network and the location of the device on the host network. When one device sends data to another, the data includes a ‘header’ that includes the IP address of the sending device and the IP address of the destination device.
Nodes: A node is a connection point inside a network that can receive, send, create, or store data. Each node requires you to provide some form of identification to receive access, like an IP address. A few examples of nodes include computers, printers, modems, bridges, and switches. A node is essentially any network device that can recognize, process, and transmit information to any other network node.
Routers: A router is a physical or virtual device that sends information contained in data packets between networks. Routers analyze data within the packets to determine the best way for the information to reach its ultimate destination. Routers forward data packets until they reach their destination node.
Switches: A switch is a device that connects other devices and manages node-to-node communication within a network, ensuring data packets reach their ultimate destination. While a router sends information between networks, a switch sends information between nodes in a single network. When discussing computer networks, ‘switching’ refers to how data is transferred between devices in a network. The three main types of switching are as follows:
- Circuit switching, which establishes a dedicated communication path between nodes in a network. This dedicated path assures the full bandwidth is available during the transmission, meaning no other traffic can travel along that path.
- Packet switching involves breaking down data into independent components called packets which, because of their small size, make fewer demands on the network. The packets travel through the network to their end destination.
- Message switching sends a message in its entirety from the source node, traveling from switch to switch until it reaches its destination node.
Ports: A port identifies a specific connection between network devices. Each port is identified by a number. If you think of an IP address as comparable to the address of a hotel, then ports are the suites or room numbers within that hotel. Computers use port numbers to determine which application, service, or process should receive specific messages.
Network cable types: The most common network cable types are Ethernet twisted pair, coaxial, and fiber optic. The choice of cable type depends on the size of the network, the arrangement of network elements, and the physical distance between devices.

Examples of computer networks

The wired or wireless connection of two or more computers for the purpose of sharing data and resources form a computer network. Today, nearly every digital device belongs to a computer network.

In an office setting, you and your colleagues may share access to a printer or to a group messaging system. The computing network that allows this is likely a LAN or local area network that permits your department to share resources.

A city government might manage a city-wide network of surveillance cameras that monitor traffic flow and incidents. This network would be part of a MAN or metropolitan area network that allows city emergency personnel to respond to traffic accidents, advise drivers of alternate travel routes, and even send traffic tickets to drivers who run red lights.

The Weather Company worked to create a peer-to-peer mesh network that allows mobile devices to communicate directly with other mobile devices without requiring WiFi or cellular connectivity. The Mesh Network Alerts project allows the delivery of life-saving weather information to billions of people, even without an internet connection.

Computer networks and the internet

The internet is actually a network of networks that connects billions of digital devices worldwide. Standard protocols allow communication between these devices. Those protocols include hypertext transfer protocol (the ‘http’ in front of all website addresses). Internet protocol (or IP addresses) are the unique identifying numbers required of every device that accesses the internet. IP addresses are comparable to your mailing address, providing unique location information so that information can be delivered correctly.

Internet Service Providers (ISPs) and Network Service Providers (NSPs) provide the infrastructure that allows the transmission of packets of data or information over the internet. Every bit of information sent over the internet doesn’t go to every device connected to the internet. It’s the combination of protocols and infrastructure that tells information exactly where to go.

How do they work?

Computer networks connect nodes like computers, routers, and switches using cables, fiber optics, or wireless signals. These connections allow devices in a network to communicate and share information and resources.

Networks follow protocols, which define how communications are sent and received. These protocols allow devices to communicate. Each device on a network uses an Internet Protocol or IP address, a string of numbers that uniquely identifies a device and allows other devices to recognize it.

Routers are virtual or physical devices that facilitate communications between different networks. Routers analyze information to determine the best way for data to reach its ultimate destination. Switches connect devices and manage node-to-node communication inside a network, ensuring that bundles of information traveling across the network reach their ultimate destination.

Architecture

Computer network architecture defines the physical and logical framework of a computer network. It outlines how computers are organized in the network and what tasks are assigned to those computers. Network architecture components include hardware, software, transmission media (wired or wireless), network topology, and communications protocols.

Main types of network architecture

There are two types of network architecture: peer-to-peer (P2P) and client/server. In P2P architecture, two or more computers are connected as “peers,” meaning they have equal power and privileges on the network. A P2P network does not require a central server for coordination. Instead, each computer on the network acts as both a client (a computer that needs to access a service) and a server (a computer that serves the needs of the client accessing a service). Each peer makes some of its resources available to the network, sharing storage, memory, bandwidth, and processing power.

In a client/server network, a central server or group of servers manage resources and deliver services to client devices in the network. The clients in the network communicate with other clients through the server. Unlike the P2P model, clients in a client/server architecture don’t share their resources. This architecture type is sometimes called a tiered model because it's designed with multiple levels or tiers.

Network topology

Network topology refers to how the nodes and links in a network are arranged. A network node is a device that can send, receive, store, or forward data. A network link connects nodes and may be either cabled or wireless links.

Understanding topology types provides the basis for building a successful network. There are a number of topologies but the most common are bus, ring, star, and mesh:

A bus network topology is when every network node is directly connected to a main cable.
In a ring topology, nodes are connected in a loop, so each device has exactly two neighbors. Adjacent pairs are connected directly; non-adjacent pairs are connected indirectly through multiple nodes.
In a star network topology, all nodes are connected to a single, central hub and each node is indirectly connected through that hub.
A mesh topology is defined by overlapping connections between nodes. You can create a full mesh topology, where every node in the network is connected to every other node. You can also create partial mesh topology in which only some nodes are connected to each other and some are connected to the nodes with which they exchange the most data. Full mesh topology can be expensive and time-consuming to execute, which is why it's often reserved for networks that require high redundancy. Partial mesh provides less redundancy but is more cost effective and simpler to execute.

Security

Computer network security protects the integrity of information contained by a network and controls who access that information. Network security policies balance the need to provide service to users with the need to control access to information.

There are many entry points to a network. These entry points include the hardware and software that comprise the network itself as well as the devices used to access the network, like computers, smartphones, and tablets. Because of these entry points, network security requires using several defense methods. Defenses may include firewalls—devices that monitor network traffic and prevent access to parts of the network based on security rules.

Processes for authenticating users with user IDs and passwords provide another layer of security. Security includes isolating network data so that proprietary or personal information is harder to access than less critical information. Other network security measures include ensuring hardware and software updates and patches are performed regularly, educating network users about their role in security processes, and staying aware of external threats executed by hackers and other malicious actors. Network threats constantly evolve, which makes network security a never-ending process.

The use of public cloud also requires updates to security procedures to ensure continued safety and access. A secure cloud demands a secure underlying network.

Read about the top five considerations (PDF, 298 KB) for securing the public cloud.

Mesh networks

As noted above, a mesh network is a topology type in which the nodes of a computer network connect to as many other nodes as possible. In this topology, nodes cooperate to efficiently route data to its destination. This topology provides greater fault tolerance because if one node fails, there are many other nodes that can transmit data. Mesh networks self-configure and self-organize, searching for the fastest, most reliable path on which to send information.

Type of mesh networks

There are two types of mesh networks—full mesh and partial mesh:

In a full mesh topology, every network node connects to every other network node, providing the highest level of fault tolerance. However, it costs more to execute. In a partial mesh topology, only some nodes connect, typically those that exchange data most frequently.
A wireless mesh network may consist of tens to hundreds of nodes. This type of network connects to users over access points spread across a large area.

Load balancers and networks

Load balancers efficiently distribute tasks, workloads, and network traffic across available servers. Think of load balancers like air traffic control at an airport. The load balancer observes all traffic coming into a network and directs it toward the router or server best equipped to manage it. The objectives of load balancing are to avoid resource overload, optimize available resources, improve response times, and maximize throughput.

For a complete overview of load balancers, see Load Balancing: A Complete Guide.

Content delivery networks

A content delivery network (CDN) is a distributed server network that delivers temporarily stored, or cached, copies of website content to users based on the user’s geographic location. A CDN stores this content in distributed locations and serves it to users as a way to reduce the distance between your website visitors and your website server. Having cached content closer to your end users allows you to serve content faster and helps websites better reach a global audience. CDNs protect against traffic surges, reduce latency, decrease bandwidth consumption, accelerate load times, and lessen the impact of hacks and attacks by introducing a layer between the end user and your website infrastructure.

Live-streaming media, on-demand media, gaming companies, application creators, e-commerce sites—as digital consumption increases, more content owners turn to CDNs to better serve content consumers.

Computer networking solutions and IBM

Computer networking solutions help businesses enhance traffic, keep users happy, secure the network, and easily provision services. The best computer networking solution is typically a unique configuration based on your specific business type and needs.

Content delivery networks (CDNs), load balancers, and network security—all mentioned above—are examples of technologies that can help businesses craft optimal computer networking solutions. IBM offers additional networking solutions, including:

Gateway appliances are devices that give you enhanced control over network traffic, let you accelerate your network’s performance, and give your network a security boost. Manage your physical and virtual networks for routing multiple VLANs, for firewalls, VPN, traffic shaping and more.
Direct Link secures and accelerates data transfer between private infrastructure, multiclouds, and IBM Cloud.
Cloud Internet Services are security and performance capabilities designed to protect public-facing web content and applications before they reach the cloud. Get DDoS protection, global load balancing and a suite of security, reliability and performance capabilities designed to protect public-facing web content and applications before they reach the cloud.

Networking services in IBM Cloud provide you with networking solutions to enhance your traffic, keep your users happy, and easily provision resources as you need them.

Build networking skills and get IBM Professional Certification through the courses within the Cloud Site Reliability Engineers (SRE) Professional curriculum.