What is Computer Networking and Topology?

Computer networking is the study of how computers can be linked to share data.

The concept of connecting computers dates back to the 1960s when the Department of Defense led the first attempt to create a computer network that painstakingly linked a handful of computers around the U.S. Since then, wireless networking has taken off and networking is now considered an essential part of computing. A computer without a network, arguably, has little use in daily life.

Computer networking involves many things coming together, and there are many challenges and important problems to solve in the field of networking:

• Scaling hardware and software to very high (e.g., 100+ Gbps) speeds (routers, switches)
• Effective interaction with the user (web technologies)
• Privacy protection and security (firewalls, antivirus software)
• Meeting growing wireless demand (smartphones, handhelds)
• Scaling the number of participants to many billions (sensors, Internet-of-Things)
• Maintaining healthy Internet economics among service providers
• Addressing social phenomena
• Seamless connection to highly mobile devices

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.

Cabling and Topology

Network Topologies
Computer networks employ many different topologies, or ways of connecting computers together. This section looks at both the historical topologies — bus, ring, and star — and the modern topologies — hybrid, mesh, point-to-multipoint, and point-to-point. In addition, we will look at what parameters are used to make up a network topology.

Bus and Ring
The first generation of wired networks used one of two topologies, both shown in Figure. A bus topology uses a single cable (the bus) that connects all of the computers in a line. A ring topology connects all computers on the network with a ring of cable.

Data flows differently between bus and ring networks, creating different problems and solutions. In bus topology networks, data from each computer simply go out on the whole bus. A network using a bus topology needs termination at each end of the cable to prevent a signal sent from one computer from reflecting at the ends of the cable, quickly bringing the network down.

In a ring topology network, in contrast, data traffic moves in a circle from one computer to the next in the same direction with no end to the cable, ring networks require no termination.

Star

The star topology uses a central connection box for all the computers on the network

Star topologies have a huge benefit over ring and bus topologies by offering fault tolerance — if one of the cables breaks, all of the other computers can still communicate. Bus and ring topology networks were popular and inexpensive to implement, however, so the old-style star topology networks weren’t very successful. Network hardware designers couldn’t easily redesign their existing networks to use a star topology.

Hybrids

Even though network designers couldn’t easily use a star topology, the benefits of star topologies were overwhelming, motivating smart people to come up with a way to use star topologies without requiring a major redesign — and the way they did so was ingenious. The ring topology network designers struck first by taking the entire ring and shrinking it into a small box,

Any form of networking technology that combines a physical topology with a signaling topology is called a hybrid topology. Hybrid topologies have come and gone since the earliest days of networking. Only two hybrid topologies, star-ring topology, and star-bus topology, ever saw any amount of popularity. Eventually, star-ring lost market share, and star-bus reigned as the undisputed king of topologies.

Mesh and Point-to-Multipoint

Topologies aren’t just for wired networks. Wireless networks also need topologies to get data from one machine to another, but using radio waves instead of cables involves somewhat different topologies. Almost all wireless networks use one of two different topologies: a mesh topology or a point-to-multipoint topology

Mesh

In a mesh topology network, every computer connects to every other computer via two or more routes. Some of the routes between two computers may require traversing through another member of the mesh network. There are two types of meshed topologies: partially meshed and fully meshed In a partially meshed topology network, at least two machines have redundant connections. Every machine doesn’t have to connect to every other machine. In a fully meshed topology network, every computer connects directly to every other computer

Point-to-Multipoint

In a point-to-multipoint topology, a single system acts as a common source through which all members of the point-to-multipoint network converse. If you compare a star topology to a slightly rearranged point-to-multipoint topology, you might be tempted to say they’re the same thing. Granted, they’re similar, but look at Figure. See what’s in the middle? The subtle but important difference is that a point-to-multipoint topology requires an intelligent device in the center, whereas the device in the center of a star topology has little more to do than send or provide a path for a signal down all the connections.

Point-to-Point

In a point-to-point topology network, two computers connect directly together with no need for a central device of any kind. You’ll find point-to-point topologies implemented in both wired and wireless networks

-Star bus topology is considered a hybrid topology

-when each host is interconnected this is considered a fully meshed topology

-Logical topology is the electronic circuit flow of frames