#readwise # Link Layer - Wikipedia  ## Metadata - Author: [[wikipedia.org]] - Full Title: Link Layer - Wikipedia - URL: https://en.wikipedia.org/wiki/Link_layer ## Summary The link layer is the lowest layer in the Internet protocol suite, handling communication between directly connected network nodes. It includes protocols like Ethernet and Wi-Fi, which are essential for local area networks. The link layer is broader than the OSI model’s data link and physical layers, covering more functions than just network access. ## Highlights In [computer networking](https://en.wikipedia.org/wiki/Computer_network), the link layer is the lowest [layer](https://en.wikipedia.org/wiki/Abstraction_layer) in the [[Internet Protocol Suite - Wikipedia|Internet protocol suite]], the networking architecture of the [Internet](https://en.wikipedia.org/wiki/Internet). The link layer is the group of methods and [communications protocols](https://en.wikipedia.org/wiki/Communications_protocol) confined to the link that a host is physically connected to. The link is the physical and logical network component used to interconnect [hosts](https://en.wikipedia.org/wiki/Host_(network)) or [nodes](https://en.wikipedia.org/wiki/Node_(networking)) in the network and a link protocol is a suite of methods and standards that operate only between adjacent network nodes of a [network segment](https://en.wikipedia.org/wiki/Network_segment). ([View Highlight](https://read.readwise.io/read/01jhq09wzkeq0hs3n6q49t5qxz)) ^gv8nvp --- Despite the different semantics of layering between the [[Internet Protocol Suite - Wikipedia|Internet protocol suite]] and [[OSI Model - Wikipedia|OSI Model]], the link layer is sometimes described as a combination of the OSI's [data link layer](https://en.wikipedia.org/wiki/Data_link_layer) (layer 2) and [physical layer](https://en.wikipedia.org/wiki/Physical_layer) (layer 1). ([View Highlight](https://read.readwise.io/read/01jhq0a4p052etd5z5egwqp0hm)) --- The link layer of the TCP/IP model is often compared directly with the combination of the data link layer and the [physical layer](https://en.wikipedia.org/wiki/Physical_layer) in the [[OSI Model - Wikipedia|Open Systems Interconnection (OSI)]] protocol stack. Although they are congruent to some degree in technical coverage of protocols, they are not identical. The link layer in TCP/IP is still wider in scope and in principle a different concept and terminology of classification. This may be observed when certain protocols, such as ARP, which is confined to the link layer in the TCP/IP model, is often said to fit between OSI's data link layer and the network layer. In general, direct or strict comparisons should be avoided, because the layering in TCP/IP is not a principal design criterion and in general, is considered to be "harmful" (RFC 3439). ([View Highlight](https://read.readwise.io/read/01jhq0bz1nf2bh1ecb6y446g3f)) ^nf0r8i ---