We are independent & ad-supported. We may earn a commission for purchases made through our links.
Advertiser Disclosure
Our website is an independent, advertising-supported platform. We provide our content free of charge to our readers, and to keep it that way, we rely on revenue generated through advertisements and affiliate partnerships. This means that when you click on certain links on our site and make a purchase, we may earn a commission. Learn more.
How We Make Money
We sustain our operations through affiliate commissions and advertising. If you click on an affiliate link and make a purchase, we may receive a commission from the merchant at no additional cost to you. We also display advertisements on our website, which help generate revenue to support our work and keep our content free for readers. Our editorial team operates independently of our advertising and affiliate partnerships to ensure that our content remains unbiased and focused on providing you with the best information and recommendations based on thorough research and honest evaluations. To remain transparent, we’ve provided a list of our current affiliate partners here.

What is a Link Level?

By S.A. Keel
Updated May 16, 2024
Our promise to you
EasyTechJunkie is dedicated to creating trustworthy, high-quality content that always prioritizes transparency, integrity, and inclusivity above all else. Our ensure that our content creation and review process includes rigorous fact-checking, evidence-based, and continual updates to ensure accuracy and reliability.

Our Promise to you

Founded in 2002, our company has been a trusted resource for readers seeking informative and engaging content. Our dedication to quality remains unwavering—and will never change. We follow a strict editorial policy, ensuring that our content is authored by highly qualified professionals and edited by subject matter experts. This guarantees that everything we publish is objective, accurate, and trustworthy.

Over the years, we've refined our approach to cover a wide range of topics, providing readers with reliable and practical advice to enhance their knowledge and skills. That's why millions of readers turn to us each year. Join us in celebrating the joy of learning, guided by standards you can trust.

Editorial Standards

At EasyTechJunkie, we are committed to creating content that you can trust. Our editorial process is designed to ensure that every piece of content we publish is accurate, reliable, and informative.

Our team of experienced writers and editors follows a strict set of guidelines to ensure the highest quality content. We conduct thorough research, fact-check all information, and rely on credible sources to back up our claims. Our content is reviewed by subject-matter experts to ensure accuracy and clarity.

We believe in transparency and maintain editorial independence from our advertisers. Our team does not receive direct compensation from advertisers, allowing us to create unbiased content that prioritizes your interests.

The link level is one of the lowest, most fundamental conceptual levels in digital communications. Basically, it's where all the logic for dealing with a data link resides. It operates in something of a hierarchy, acting as an interface, in this case, between the lowest level, the physical level that transmits the raw stream of ones and zeros, and the upper layers. In many cases, the term is used interchangeably with "link layer," which typically signifies the open systems interconnection (OSI) model's second layer, the data link layer, used in computer networking. There are numerous communication protocols that operate at the link level, but its essential functions are to prepare the data packets intended for transport as well as interpret any incoming via the data link.

There are three types of data links that a link level has to deal with: simplex, half-duplex, and full duplex. With a simplex link, the data travels in one direction, such as a broadcast network, where there is a dedicated sender and recipient, and the recipient doesn't need to send anything back to the sender. With half-duplex, the data can go both ways, but not at the same time. Full-duplex communications allow for data to travel in both directions simultaneously, which requires more effort on behalf of the link level to sort out the communications that are coming and going.

To do much of its work, the link level uses a technique known as framing. This involves tacking on an extra identifier which indicates where the frame begins or ends in the bit stream. Though other framing methods exist, in most cases, this is simply an extra bit added into the stream during specific increments. On the receiving end, the link layer synchronizes the framing bits in the stream to help separate out the frames, pull out the original packets, and pass them up the other layers as necessary. The synchronization between the sending and receiving ends is important, because if the receiving link layer happens to pick up the stream between frames, it can simply wait until the next frame begins, discarding any unusable bits that don't belong to a frame.

The OSI model's data link layer further perceives two sub-layers to the link layer. One is referred to as the logical link control (LLC), while the other is the media access control (MAC). The upper, LLC sub-layer deals with issues such as flow control and fixing errors in the transmission. Depending on the type of communication, some error correction methods may not be employed. For example, with wireless networking, the link level has the ability to request erroneous packets be sent again, which is much more rare in wired communications where the link layer only deals with detecting errors and canceling bad packets.

The lower MAC sub-layer is then responsible for identifying the physical address of the device, commonly referred to as the MAC address. It is also capable of maintaining any queuing of the data packets, as well as scheduling their delivery and ensuring the quality of the transmission. This is also where the frame synchronization takes place, as well as protocols that keep the streams from colliding.

EasyTechJunkie is dedicated to providing accurate and trustworthy information. We carefully select reputable sources and employ a rigorous fact-checking process to maintain the highest standards. To learn more about our commitment to accuracy, read our editorial process.
Discussion Comments
EasyTechJunkie, in your inbox

Our latest articles, guides, and more, delivered daily.

EasyTechJunkie, in your inbox

Our latest articles, guides, and more, delivered daily.