Common Computer Networking Terms

This is a plain-English glossary of the networking and IT terms a business owner meets on quotes, invoices and in conversations with technicians, from access point to zero trust. It was first published in 2012 and has been updated in September 2026: the definitions are current, obsolete terms are marked as such, and the terms that did not exist or did not matter in 2012, Wi-Fi 6, MFA, EDR, VLAN, DMARC and the rest, are here now. For a searchable version, see our IT glossary.

A

• Access list – A list a router or firewall keeps to decide which traffic may pass, by address, port or service. The basis of every firewall rule.
• Access point – A device that provides Wi-Fi to an area, connected by cable to the switch. Offices use several, placed centrally and managed together, rather than one router in a corner.
• Adapter – The hardware that gives a computer or device physical access to a network, wired or wireless.
• Address – A number or name that uniquely identifies a device or service on a network.
• Algorithm – A defined set of rules for performing a task, such as compressing a file or encrypting a message.
• Alphanumeric – Letters and numbers, with a limited set of symbols; what most usernames and passwords are made of.
• API – Application programming interface. The published way one piece of software talks to another, so that, for example, your accounting system can pull data from your CRM.
• Architecture – The overall design of a network or system: what the pieces are and how they connect.
• Archive – Storage for data that is rarely used but must be kept, as distinct from a backup, which is a copy for recovery.

B

• Back end – The servers and software behind a service that the user never sees directly.
• Background task – Work a computer performs while you are doing something else, such as a backup or a scan.
• Bandwidth – The capacity of a connection, usually given in megabits or gigabits per second. Upload and download bandwidth are often different.
• Benchmark – A test that measures performance so that two systems, or one system before and after a change, can be compared.
• Binary – Data in the form computers use, ones and zeros.
• Bitrate – The number of bits transmitted per second, used for network links and for audio and video quality.
• Boot drive – The drive holding the operating system a computer starts from.
• BPS – Bits per second, the base unit of transmission speed, prefixed K, M or G for thousands, millions or billions.
• Broadband – A high-capacity, always-on internet connection: fiber, cable or fixed wireless.
• Buffer – Temporary memory that smooths the flow of data between two things running at different speeds.
• Bug – A flaw in software.

C

• Cache – Temporary storage of frequently used data so it can be retrieved quickly; browsers, DNS servers and processors all have one.
• Case insensitive and case sensitive – Whether upper and lower case letters are treated as the same. Email addresses are case insensitive; most passwords are case sensitive.
• Category cabling (Cat5e, Cat6, Cat6a) – The copper network cable standards. Cat5e carries gigabit Ethernet over 100 meters; Cat6 and Cat6a carry 10 gigabit over shorter and full distances respectively. Plain Cat5 is obsolete and should be replaced. Cat7 and Cat8 exist for data centers.
• Checksum – A calculated value used to confirm that data arrived intact.
• Client/server – A relationship in which one computer, the client, requests something and another, the server, provides it. Most business software works this way, with the server on site or in the cloud.
• Cloud – Servers, storage and software owned and run by another company, reached over the internet and paid for monthly. Microsoft 365 and Azure, Google Workspace and Amazon Web Services are the large examples.
• Codec – A method of encoding and decoding audio or video, such as the ones VoIP phones use to compress voice.
• Compression – Making data smaller for storage or transmission.
• CPU – Central processing unit; the main processor.

D

• Database – Structured data that software can search and update; nearly every business application keeps its information in one, usually on a database server.
• Decryption – Turning encrypted data back into its readable form with the correct key.
• Device driver – Software that lets the operating system use a piece of hardware, such as a printer or network card.
• DHCP – Dynamic Host Configuration Protocol. The service that automatically gives each device on the network an IP address, so nobody has to type one.
• DKIM – DomainKeys Identified Mail. A signature added to outgoing email that lets receiving servers confirm the message really came from your domain and was not altered.
• DMARC – A policy published in DNS that tells receiving servers what to do with mail that fails SPF or DKIM checks, and sends you reports. The three together stop your domain being impersonated.
• DNS – Domain Name System. The service that turns names such as oactechnology.com into IP addresses. A slow or failing DNS server makes a fast connection feel slow.
• Domain – A named area of the internet, such as a company’s domain name; also, in Windows networks, the set of computers and users managed together by a domain controller.
• Drive – A data storage device: a hard drive with spinning platters, or a solid-state drive using flash memory.

E

• Email – Messages carried between mail servers over the internet; the most common way attacks reach a business.
• EDR – Endpoint detection and response. Security software on each computer and server that watches behaviour rather than just known files, and can isolate a machine when something is wrong.
• EMI – Electromagnetic interference, which degrades signals on copper cable run near power lines or motors; a reason to use fiber in some buildings.
• Encoder – A device or program that converts information into a form suitable for transmission.
• Encryption – Scrambling data with a key so that only someone with the key can read it; used for laptops, websites, email and backups.
• Endpoint – Any device that connects to the network or to cloud accounts: laptops, desktops, servers, phones, tablets. Each is a possible way in for an attacker.
• Ethernet – The standard for wired local networks, from the cable and connectors to the rules for sending data.
• Extension – An add-on that extends the functions of a program, such as a browser extension; also the last part of a file name that indicates its type.

F

• FCC – The Federal Communications Commission, which regulates communications in the United States.
• Fiber-optic cable – Cable that carries data as light. Immune to electrical interference, capable of very high speeds over long distances, and now the preferred internet connection for offices where it is available.
• File transfer – Moving a file from one device to another over a network.
• Firewall – The device between your network and the internet that decides what may pass in either direction, and in a business also inspects traffic for threats, filters content and terminates VPNs.
• FireWire – A legacy high-speed connector for external drives and cameras, replaced by USB and Thunderbolt.
• Firmware – Software stored inside a device, such as a firewall, switch or printer, that makes it work. Firmware needs updating like any other software; unpatched firewall firmware is a common way in.
• Flash memory – Storage that keeps data as electrical charge with no moving parts; what solid-state drives, USB sticks and memory cards use. A magnet cannot affect it.
• FTP – File Transfer Protocol, an old method of moving files between computers. Unencrypted, so its secure successors SFTP and FTPS are used today.

G

• Gateway – The device that connects your network to another, usually the firewall or router that leads to the internet.
• GB, Gb, GBps, Gbps – Gigabyte, gigabit, gigabytes per second and gigabits per second. A byte is eight bits, so a 1 Gbps connection moves about 125 megabytes per second.
• GHz – Gigahertz, a measure of frequency used for processor speed and for the Wi-Fi bands: 2.4 GHz, 5 GHz and 6 GHz.
• Gigabit Ethernet – Wired networking at 1,000 megabits per second, the standard for office desks; 2.5 and 10 gigabit are common for servers and access points.
• GUI – Graphical user interface; windows, icons and a mouse rather than typed commands.

H

• Hacker – Someone who bypasses security measures; in practice, usually a criminal group working for money.
• Hardware address – See MAC address.
• HTML – Hypertext markup language, the format web pages are written in.
• HTTPS – The encrypted version of the web protocol, shown by the padlock in the browser. Any site handling logins or data should use it.

I

• IP address – The numerical address of a device on a network. IPv4 addresses look like 192.168.1.10 and are in short supply; IPv6 addresses are much longer and effectively unlimited. Offices use private addresses inside and one or more public addresses on the internet side of the firewall.
• IPv6 – The current version of the internet protocol, with a vastly larger address space than IPv4. Most internet providers and devices support it; our guide to IPv6 versus IPv4 explains what it means for a business.
• ISP – Internet service provider, the company that sells you the connection.

J

• Jitter – Variation in the delay between packets. Low jitter matters for voice and video calls; high jitter makes them choppy.

K

• KB, Kb, KBps, Kbps – Kilobyte, kilobit and their per-second rates; a kilobyte is 1,024 bytes in most contexts.

L

• LAN – Local area network: the network within one office or building.
• LAN server – A server on the local network that provides files, printing, applications or authentication.
• Latency – The time a packet takes to travel from one point to another, measured in milliseconds. Latency, not bandwidth, is what makes a distant server feel slow.
• Leased line – A dedicated connection reserved for one customer, such as a T1 was; today usually dedicated fiber.
• Line of sight – A clear path between two points, required by microwave and some fixed-wireless internet links.
• Load balancing – Spreading traffic across several links or servers so that no single one is overloaded and the failure of one is survivable.

M

• MAC address – The unique hardware address burned into every network adapter, used on the local network to deliver traffic to the right device.
• Mbps and MB – Megabits per second and megabytes. Connection speeds are quoted in bits; file sizes in bytes; divide by eight to convert.
• MDR – Managed detection and response: a 24/7 team of analysts watching endpoint detection alerts and responding to them, which a small business cannot staff itself.
• Memory – See RAM.
• Mesh Wi-Fi – Several wireless units that cooperate to cover an area; a home product in most cases, with managed access points doing the same job in offices.
• MFA – Multi-factor authentication: a second proof of identity at sign-in, such as an app prompt, a code or a security key, so that a stolen password alone is not enough. The single most effective security control for a small business.
• Modem – The device that converts the provider’s signal, on cable, fiber or phone line, into Ethernet.
• Multitasking – Running several tasks at once, which every modern operating system does.

N

• Name server – A server that answers DNS queries.
• NAT – Network address translation. What the firewall does to let many devices with private addresses share one public address on the internet.
• Network adapter – See adapter.

O

• OEM – Original equipment manufacturer; equipment sold by one company but made by another, or software licensed with the hardware it came on.

P

• Packet – A small unit of data with an address on it; everything on a network travels as packets.
• Patch – An update that fixes a security flaw or bug. Patching on a schedule is a basic security control; unpatched systems are attacked first.
• Peripheral – Hardware attached to a computer, such as a printer, scanner or external drive.
• Phishing – Fraudulent email, text or calls designed to get a password, a payment or a click. The starting point of most breaches at small businesses.
• Ping – A diagnostic that sends a small packet to another device and times the reply, showing whether it is reachable and how far away it feels.
• PoE – Power over Ethernet: network cable that also carries power, so phones, access points and cameras need no power outlet.
• Port – A numbered channel a service listens on, such as 443 for HTTPS; also a physical socket on a switch.
• Print spooler – Software that accepts print jobs and queues them for the printer.
• Proprietary – Owned and controlled by one company, as opposed to an open standard.
• Protocol – An agreed set of rules for communication, such as TCP/IP, HTTPS or SIP.

Q

• QoS – Quality of service: firewall and switch settings that give voice and video traffic priority over downloads so calls stay clear when the connection is busy.

R

• Ransomware – Malware that encrypts a business’s data and demands payment for the key, usually after stealing a copy of the data first.
• RAM – Random access memory; the fast working memory a computer uses while running, separate from storage.
• Reboot – Restarting a computer without removing power.
• Router – A device that forwards packets between networks. In an office the firewall usually performs this role.

S

• SaaS – Software as a service: applications delivered from the cloud on subscription, such as Microsoft 365 or QuickBooks Online.
• Scalability – How well a system keeps working as it grows.
• SD-WAN – Software-defined wide area networking, which manages several internet connections at each site and routes traffic over the best one; used by multi-site businesses.
• Server – A computer that provides files, applications, identity or other services to other computers over the network; physical, virtual or cloud-hosted.
• SIP – Session Initiation Protocol, the signalling standard for VoIP phone systems; a SIP trunk is the connection between a phone system and the telephone network.
• SPF – Sender Policy Framework: a DNS record listing which servers may send email for your domain. One of the three email authentication records with DKIM and DMARC.
• SQL – Structured Query Language, the language used to work with databases; Microsoft SQL Server is the common business database.
• SSID – The name of a Wi-Fi network.
• Static and dynamic IP – A static address is fixed; a dynamic one is assigned automatically and may change. Servers and the firewall use static addresses; everything else uses DHCP.
• Subnet – A division of a network into a smaller address range, used to separate departments, guests or equipment.
• Switch – The device that connects the wired devices in an office together. Managed switches can be configured, monitored and divided into VLANs; unmanaged ones cannot.

T

• T1, T2, T3 – Legacy dedicated telephone-company circuits at 1.5, 6.3 and 45 megabits per second, once the business standard and now replaced by fiber.
• TCP/IP – The pair of protocols the internet and every modern network run on.
• Telco – Telephone company.
• Time-out – What happens when a device waits for a reply that never comes; the usual result is a retry or an error.
• Transfer rate – The speed at which data moves between two devices.
• Trojan horse – Malware disguised as something legitimate, such as an attachment or a fake antivirus program, that the user installs.
• Truncate – To cut data off at a set length.
• Tweak – A minor adjustment.

U

• Upload – Sending data from your device to a remote system; the upload speed of a connection is what video calls and cloud phones depend on.
• UPS – Uninterruptible power supply: a battery unit that keeps servers and network equipment running through a short outage and shuts them down cleanly in a long one.

V

• Virus – Malicious code that attaches itself to programs or files and spreads; today a subset of malware generally.
• VLAN – Virtual LAN: a way to divide one physical network into separate logical ones, so that guests, phones, cameras and staff computers cannot see each other.
• VoIP – Voice over internet protocol: telephone calls carried over the internet, which is how nearly every business phone system now works.
• VPN – Virtual private network: an encrypted connection between a remote user or office and the company network, or between two sites.

W

• WAN – Wide area network: a network spanning distant sites, usually over the internet or leased circuits.
• Wi-Fi 6, 6E and 7 – The current generations of wireless networking. Wi-Fi 6 handles many devices far better than its predecessors; 6E adds the uncrowded 6 GHz band; Wi-Fi 7 adds speed and lower latency on top.
• Wireless – Communication without cables, whether Wi-Fi in the office or cellular from the carrier.
• Workgroup – A small set of computers sharing resources without a domain controller; fine for a handful of machines, unmanageable beyond that.

Z

• Zero trust – A security approach in which no device or user is trusted because of where it is; every access is verified, with MFA, device checks and least-privilege permissions.

Most businesses do not need to know all of this

They need someone who does. Our network support and network security services exist so that the terms above are our problem rather than yours, and our guides to slow internet, servers and IPv6 versus IPv4 go deeper on the ones that come up most.

Common questions

What is the difference between bandwidth and latency?

Bandwidth is how much data a connection can carry per second; latency is how long each packet takes to arrive. A connection can have plenty of bandwidth and still feel slow if latency is high, which is why a distant cloud server responds sluggishly even on fast fiber.

What is the difference between a router, a switch and a firewall?

A switch connects the devices inside the office. A router forwards traffic between networks. A firewall does the routing to the internet and decides what may pass, inspecting traffic for threats. In a small office one business firewall does the routing and security, and switches do the connecting.

What do SPF, DKIM and DMARC do?

Together they let receiving mail servers confirm that email claiming to be from your domain really is. SPF lists your sending servers, DKIM signs each message, and DMARC tells receivers what to do when a check fails and reports back to you. Without them your domain can be impersonated freely.

What is the difference between Mbps and MB?

Mbps is megabits per second, used for connection speeds. MB is megabytes, used for file sizes. There are eight bits in a byte, so a 100 Mbps connection moves about 12.5 megabytes per second.

Which of these terms matter most for a small business?

MFA, EDR and patching for security; bandwidth, latency and Wi-Fi 6 for a network that works; SPF, DKIM and DMARC for email that arrives; and VLANs and a business firewall for keeping guests, cameras and phones apart from the computers that hold your data.

Talk to us

Call 952-548-5558 or contact us; the first conversation is free and there is no long-term contract.