What is a network interface card, or NIC?

What is a network interface card? What is a NIC? It’s a term you may not hear as much anymore as you once did. But a network interface card is the computer component that lets you plug it into an Ethernet network or connect to a wireless network to get LAN and/or Internet access.

Network interface cards can come with anywhere from one to four ports. One port is the most common. Multi-port cards allow you to bond more than one port together for greater speed. Or you can use them for failover, or to dedicate a port to a specific virtual machine in virtual environments.

Why it’s called a network interface card, or NIC

what is a network interface card or NIC
Network interface cards plug into a slot on a motherboard and usually come with one network port, but some come with two or four. This one plugs into a low-profile slot for a smaller system. It features two ports and plugs into a PCI Express slot. A heatsink covers the chipset, but I happen to know this is an Intel-based card.

Today, motherboards often include the functionality that used to come on network cards. But for many years, it was a discrete component. Integrating it into the motherboard, and even into one of the other chips on a motherboard, tends to save costs. Back when it was an expensive component that not everyone wanted or needed, it made sense to make the NIC an option.

Some people might not consider integrated networking a NIC anymore. But others still call it that.

Types of plug-in interfaces

Network interface cards exist for just about any type of bus that might be available to plug it into. The most common are PCI, PCI Express (PCIe), and USB. But in the past, network interface cards existed for ISA, Microchannel, Nubus, PCMCIA, parallel ports, and likely some other standards I’m forgetting.

In some cases, especially in compact servers, the network interface card is on a daughterboard that plugs into an odd connector. It’s still connecting to a bus on the motherboard when it plugs in this way, but using a different connector allows them to save space.

Even when the network chip is soldered onto the motherboard, it’s still connecting to the PCI or PCI Express bus, but it’s not taking up a slot. When it’s integrated into another chip, such as what Intel does on some server and workstation motherboards, it’s still making a PCI Express connection. But it saves some cost and some space on the board. And that’s why I don’t get too uptight when someone calls it a NIC even though it’s not a separate component.

Brands of network chipsets

Today three companies make more network chips than anyone else: Broadcom, Intel, and Realtek. Of the three, Realtek is the least expensive and the most common in consumer-grade computers. Intel is the most expensive. You’ll usually find Intel and Broadcom in more expensive, business-grade systems.

I’ve gotten dragged into arguments about whether Intel or Broadcom cards are better. On Windows systems, I don’t see much difference between the two. Intel does a better job of supporting Linux, but I’ve never had any trouble with Broadcom cards in Linux. Broadcom cards don’t work as well in BSD-based operating systems, including Mac OS X.

Intel sells cards directly, but all the major server manufacturers also resell both Intel and Broadcom cards. Many companies sell Realtek-based cards, including companies like Netgear and D-Link, and also many no-name companies. You can buy generic Realtek-based cards from Ebay for a couple of dollars. I don’t recommend it, but you can. I’ve talked about Realtek vs Intel before.

I typically swap cards when I have trouble, and replace Realtek cards with used Intel or Broadcom cards. It’s not hard to find used Broadcom cards for $10 and used Intel cards for $15. I’d paid as little as $3 for used Broadcom cards before. I wish I’d bought a couple of extra when I scored that one. I use used enterprise-grade cards at home, but I once worked for a Fortune 20 company that used a lot of used equipment, so don’t feel bad about used NICs at work.

Types of networks

Today we think of two types of network interface cards: wired and wireless. And maybe we think about speed, and the distinction between copper and fiber. There was a time when there were several types of wired networks, but Ethernet won over the other standards because it didn’t require paying any royalties. The cheap, good-enough solution usually wins in the marketplace, and royalty-free Ethernet is one of the better examples of this.

Fiber is more secure than copper and can run for longer distances without degrading. The fastest speeds also come available for fiber before they do for copper. But copper tends to be cheaper, and needs less specialized equipment to use, so copper is more common.

What is a network interface card, or NIC?

What is a network interface card, or NIC? Hopefully now you know. And there may be more to the question than you first thought.

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