What is the level of the link?
The connection level is one of the lowest and most basic conceptual levels in digital communication. In principle, it is a place where all logic for data connection is located. It works in something hierarchy and acts as an interface in this case among the lowest level, a physical level that transmits the raw stream of those and zeros and upper layers. In many cases, the term is used interchangeably with "Link Layer", which usually means the second layer of Open Systems Interconnection (OSI), a layer of data connection that is used on a computer network. There are many communication protocols at the connection level, but its basic functions are preparation of data packets designed for transport and interpret any incoming via data connection.
There are three types of data links that the connection level must deal with: simplex, half duplex and full duplex. With a simplex link, the data moves in one direction like a broadcast net where TZDE is specialized fromThe ESEMBER AND RECOMMENDER AND POPER does not have to send anything back to the sender. In half duplex, data can go in both ways, but not at the same time. Full-double communication allows data to travel in both directions simultaneously, which requires more effort on behalf of the link level to solve communication that comes and leaves.
To perform a large part of our work, the level of connection uses a technique known as framing. This includes attachment on another identifier that indicates where the frame begins or ends in a bit current. Although there are other framing methods, in most cases it is extra somewhat added to the current during specific additions. At the end of the receiving end, it synchronizes the layer of framing bits in the stream to help separate the frames, pull out the original packets and pass it on other layers as needed. Synchroje important because if the current is picked up between the frameEčky, he can simply wait for other images that another, throw away any non -commercial bits that do not belong to the frame can simply wait for more images to pick up the current between the frames, simply wait for the next images to throw away.
The OSI data connection layer also perceives two sub -layers into the connection layer. One is referred to as Logical Link control (LLC), while the other is a media access control (MAC). The upper partial layer LLC deals with problems such as flow control and transmission errors. Depending on the type of communication, some error correction methods may not be used. For example, with a wireless network, the link level has the possibility to request erroneous packets, which is much more rare in the cable communication, where the connection layer only detects errors and cancellation of bad packets.
The lower partial layer Mac is then responsible for identifying the physical address of the device, the commonly known as the MAC address. Is also withCHOPEN to maintain any queue of data packets and also plan their delivery and ensure the quality of transmission. This is also a place where frames are synchronized, and protocols that prevent the flow of flows.