This post will cover various aspects of the Networking section of the CompTIA A+ Core 1 certification endeavor.
Table of contents
Internet connection types
An internet service provider (ISP) is a company that provides access to the internet. ISPs can provide this access through multiple means, including dial-up, DSL, cable, wireless and fiber-optic connections.
A variety of companies serve as ISPs, including cable providers, mobile carriers, and telephone companies. In some cases, a single company may offer multiple types of service (i.e. cable and wireless), while in other cases, a company may focus on just one type of service (i.e. fiber-optic). Without an ISP, individuals and businesses could not reach the internet and the opportunities it provides.
An ISP is required in order to connect to the internet via a modem in your home or business. Without an ISP, you would not be able to access the wealth of information available online. An ISP can provide you with a fast and reliable connection.
Fiber (FiOS)
FiOS (Fiber Optic Service) is a fiber to the premises (FTTP) telecommunications service offered by Verizon to consumers in the United States. The word “fios” is Irish for “knowledge” and the FiOS acronym is a trademark of Verizon. FTTP, also called “fiber to the home” (FTTH), is the installation and use of optical fiber from a central point directly to individual buildings.
Fiber optic communications is one of the more expensive type of internet connections that comes with a great amount of bandwidth. Download speeds range from 10 to 50 Mbps, and upload speeds can run up to 20 Mbps. You can get up to gigabit, and sometimes even beyond depending on the area. It is available in certain areas, and some of them are not available in certain areas.
Cable
When we talk about cable, we’re talking about the coaxial cable type implementations, when it comes to network communications. Coaxial cables are probably one of the oldest network technologies, we have in the industry today.
A coaxial — or coax — cable is primarily used by cable TV companies to connect their satellite antenna facilities to customer homes and businesses. Telephone companies also sometimes use coax cable to connect central offices to telephone poles near customers. They use a technology called DOCSIS; Data-over-Cable Service Interface Specifications which defines technical specifications for equipment at both subscriber locations and cable operators’ headends. Adoption of DOCSIS accelerates the deployment of data-over-cable services and will ensure interoperability of equipment throughout system operators’ infrastructures.
Dial-up
The public switched telephone network, or PSTN, is the world’s collection of interconnected voice-oriented public telephone networks. PSTN is the traditional circuit-switched telephone network. PSTN comprises all the switched telephone networks around the world that are operated by local, national or international carriers. These networks provide the infrastructure and services for public telecommunication.
This is the system that has been in general use since the late 1800s. It’s the aggregation of circuit-switching telephone networks that has evolved from the days of Alexander Graham Bell. Using underground copper wires, this legacy platform has provided businesses and households alike with a reliable means to communicate with anyone around the world for generations. Today, it is almost entirely digital.
Modern dial-up modems typically have a maximum theoretical transfer speed of 56 kbit/s (using the V. 90 or V. 92 protocol), although in most cases, 40–50 kbit/s is the norm. Factors such as phone line noise as well as the quality of the modem itself play a large part in determining connection speeds. Dial up is still in use in areas where there aren’t cables that can be run. Whether isn’t maybe the ability to for whatever reason or another, have satellite. When your other network connections get hit with natural disasters dial up is used in disaster recovery.
DSL
DSL (Digital Subscriber Line) is a modem technology that uses existing telephone lines to transport high-bandwidth data, such as multimedia and video, to service subscribers. DSL provides dedicated, point-to-point, public network access which gives you this ability to use the telephone and the internet at the same time. It also allows for a lot greater speeds than dial-up.
The speeds that DSL gets is directly related to the distance from the telecommunication providers switch. DSL has a maximum distance of around 18,000 feet. The further away you are with the switch, more likely the slower your connection is gonna be.
Cellular
A cellular network or mobile network is a telecommunications network where the link to and from end nodes is wireless and the network is distributed over land areas called cells, each served by at least one fixed-location transceiver (typically three cell towers or base transceiver stations). This particular technology does rely on different cell towers and they’re spaced apart. So hopefully what happens is you can actually continue to drive and not drop that connection, that actually seems like a big drop at all. Now with that though, that is not the farthest in other words that’s not the longest distance type of connection that we have with.
Satellite
Most satellite internet services come from single geostationary satellites that orbit the planet at 35,786 km. As a result, the round trip data time between the user and satellite—also known as latency—is high, making it nearly impossible to support streaming, online gaming, video calls or other high data rate activities. It also suffers from conditions such as weather.
Wireless Internet service provider (WISP)
Fixed wireless internet service providers (WISPs) deliver reliable, affordable broadband to customers in fixed locations such as residences, businesses, and schools.
Fixed wireless is the fastest-growing sector of the broadband industry, characterized by cost-effective deployment, rapid technology innovation, and continuously evolving transmission models, including fiber. Networks can be built and upgraded virtually overnight at a fraction of the cost of wired-only or satellite technologies.
Network types
Personal area network
A personal area network (PAN) is the smallest and simplest type of network. PANs connect devices within the range of an individual and are no larger than about 10 meters (m). Because PANs operate in such limited areas of space, most are wireless and provide short-range connectivity with infrared technology.
An example of a wireless PAN is when users connect Bluetooth devices, like wireless headsets, to a smartphone or laptop. Although most PANs are wireless, wired PAN options exist, including USB.
Some benefits of PANs include:
- Portability — Most devices that connect in a PAN are small and can be easily transported.
- Affordability — The ability to form a connection between two devices in a PAN without additional wiring is generally less expensive compared to a wired network.
- Reliability — PANs guarantee stable connectivity between devices, provided that the devices remain within the 10 m range.
- Security — PANs don’t directly connect to larger networks, but rather to other devices connected to larger networks. The security of a device in a PAN is contingent upon how secure the intermediary device is within the larger overall network.
PANs are configured so individual users can connect their devices within their personal vicinity. A literal example of this is a body area network, in which a user physically wears connected devices. Small home networks with computers, printers and other wireless devices are also considered PANs.
Looking ahead, PANs could function as a key player in the world of futurology. Some networking experts have predicted that PANs may be able to optimize and enable IoT systems in both offices and homes.
Local area network
A local area network (LAN) is a system where computers and other devices connect to each other in one location. While PANs connect devices around an individual, the scope of a LAN can range from a few meters in a home to hundreds of meters in a large company office. The network topology determines how devices in LANs interconnect.
LANs use both wired and wireless connectivity options. Wireless LAN (WLAN) has surpassed traditional wired LAN in terms of popularity, but wired LAN remains the more secure and reliable option. Wired LANs use physical cables, like Ethernet, and switches; WLANs use devices, like wireless routers and access points, to interconnect network devices through radio frequency waves.
Network administrators can implement security protocols and encryption standards to secure wireless networks. Wired LANs are usually more secure because they require a physical cable to form a connection and are far less susceptible to compromise.
Some benefits of LANs include:
- Resource sharing — Resource sharing is one of the most important reasons for setting up any network. As more devices connect to each other, they can share more files, data and software among each other.
- Secure data storage — Network data is stored in a centralized location that all connected devices can access. Devices must receive permission to access the network, preventing unauthorized users from retrieving sensitive information.
- Fast communication — Ethernet cables provide fast, reliable data transmission speeds, which increase the rate of communication between devices.
- Seamless communication — Any authorized user can communicate with another on the same network.
LANs support home offices and corporate network environments, among others. Users in personal home offices can connect their devices and transfer data between each device with little error. Employees in company offices can quickly communicate, share and access the same data and services provided by their organization.
The most common WLAN use case is Wi-Fi. A wireless network can use Wi-Fi radio signals to connect multiple devices in a single location. It’s important to note, though, that WLAN and Wi-Fi differ. A Wi-Fi network is a WLAN, but not all WLANs use Wi-Fi.
Metropolitan area network
A metropolitan area network (MAN) is an interconnection of several LANs throughout a city, town or municipality. Like LANs, a MAN can use various wired or wireless connectivity options, including fiber optics, Ethernet cables, Wi-Fi or cellular.
Some benefits of MANs include:
- Municipal coverage — A MAN can span an entire city or town, stretching network connectivity by dozens of miles.
- Efficient networking standards — MAN configurations typically use IEEE 802.11 networking standards to increase bandwidth capacity and frequency levels, which boost network performance.
- High-speed connectivity — Fiber optic cables are the most popular form of MAN connectivity because they provide safe and fast connection data rates.
The main purpose of a MAN is to have the same network available in several locations. In a LAN, the network is accessible in one location. In a MAN, organizations with LANs in the same municipality — such as different office buildings — can extend their network connectivity to those different locations.
Government entities may also configure a MAN to provide public network connectivity to users. An example of this is when municipalities offer free, public Wi-Fi to city residents using wireless MAN technology.
Campus network
A campus network, sometimes referred to as a campus area network or CAN, is a network of interconnected, dispersed LANs. Like MANs, campus networks extend coverage to buildings close in proximity. The difference between the two configurations is that campus networks connect LANs within a limited geographical area, while MANs connect LANs within a larger metro area. The geographical range of a campus network varies from 1 kilometer to 5 km, while MANs can extend to 50 km.
Some benefits of campus networks include:
- Affordability — Campus networks cover a smaller geographical area than MANs, so infrastructure costs less to maintain.
- Easy configuration — Compared to MANs, campus networks are easier to set up and manage because there is less ground to cover and fewer devices to support.
- Wi-Fi hotspot creation — Universities and other organizations with campus networks may set up free Wi-Fi hotspots in areas with high volume to enable easy network access.
Network administrators commonly set up campus networks to create networks large enough to cover a school or university. The term campus network might imply that these networks work only for university environments, but businesses also set up campus networks to distribute one standardized network across buildings in a localized area.
Wide area network
A wide area network (WAN) is the most expansive type of computer network configuration. Like a MAN, a WAN is a connection of multiple LANs belonging to the same network. Unlike MANs, however, WANs aren’t restricted to the confines of city limits. A WAN can extend to any area of the globe. For example, an organization with a corporate office in New York can connect a branch location in London in the same WAN. Users in both locations obtain access to the same data, files and applications, and can communicate with each other.
Some benefits of WANs include:
- Large area coverage — WANs provide more expansive connectivity because networks can connect from anywhere in the world.
- Improved performance — WANs use links with dedicated bandwidth to connect LANs together. These links enhance network speeds and provide faster data transfer rates than LANs.
- Increased security — Dedicated links also increase safety across the network because the network only connects to itself, lowering the chances for hackers to hijack a system.
The main draw of a WAN is its facilitation of long-distance network connectivity. Organizations use WANs to connect branch offices located away from headquarters. But businesses aren’t the only ones that can use WANs; an estimated two-thirds of the global population uses the internet — the world’s most popular and largest WAN — today.
Content delivery network
A content delivery network (CDN) is a network of globally distributed servers that deliver dynamic multimedia content — such as interactive ads or video content — to web-based internet users. CDNs use specialized servers that deliver bandwidth-heavy rich media content by caching it and speeding up delivery time. CDN providers deploy these digitized servers globally at a network edge, creating geographically distributed points of presence.
When a user requests data in a network, a proxy server forwards the data to the nearest CDN server, which encrypts it into a smaller, more manageable file for the network to handle, before delivering it to the origin server. An origin server provides the content to the user.
CDNs are fairly simple to configure, and organizations have many CDN vendor options from which to purchase services.
Some benefits of CDNs include:
- Fast content delivery — The main goal of a CDN is to load rich media content on websites quickly and reduce latency between requests.
- Increased security — When traffic travels through a CDN server, potential viruses attached to data reroute to the server, too. A CDN service mitigates these threats so it can send uncompromised data through the network.
- Improved site performance — Websites managed by CDNs experience less latency and bandwidth limitation issues. Network downtime caused by traffic spikes is also a rare occurrence in websites with CDNs.
CDNs enable the delivery of rich — i.e., dynamic — media. Most websites and applications incorporate some form of dynamic content, from embedded social media posts to video-streaming players. CDNs are more important than ever for accommodating the vast amount of complex data shared among millions of internet users each day.
Virtual private network
A virtual private network (VPN) creates a private network overlay across an existing public network. VPNs use tunneling protocols that create encrypted connections between the network and client devices. Network traffic travels over the VPN service’s secure, encrypted tunnels instead of a public network, effectively hiding a user’s IP address and data from ISPs and cybersecurity hackers. The user’s location appears to be wherever the VPN server exists.
Some benefits of VPNs include:
- Privacy and anonymity — Users can browse a network without having their activity monitored by an ISP.
- Increased security — Users must receive authentication before gaining access to a VPN. Organizations can secure company data this way by preventing unauthenticated users from accessing sensitive information.
- Geo-spoofing — Users connected to VPNs appear to be in the same location as the server, whether in an office building or another country entirely. Users can retrieve company data or gain access to geo-blocked content outside of their country’s borders.
Studies show that VPNs have risen in popularity in recent years as internet users seek to browse the web without surveillance from their ISPs. An ISP can monitor a user’s web activity, including sites visited and the types of content downloaded. VPNs hide this information from an ISP, while still providing the user with access to the network service.
VPNs also facilitate remote work for individuals working outside of office locations. User devices with VPN client software can connect to their organization’s VPN server and receive access to their office’s data center. Using that connection, they can access the same files and resources as employees who are physically located in the building. This functionality made VPN a vital tool during the COVID-19 pandemic, when more than a third of the U.S. labor force worked from home, per Pew Research Center.