Osi Data Link Layer Pdf Data link layer is responsible for converting data stream to signals bit by bit and to send that over the underlying hardware. at the receiving end, data link layer picks up data from hardware which are in the form of electrical signals, assembles them in a recognizable frame format, and hands over to upper layer. data link layer has two sub. Data link layer (dll) is the second layer of the osi model which takes services from the physical layer and provides services to the network layer. dll transfers the data from a host to a node or a node to another node.
03 The Osi Data Link Layer Pdf Osi Model Network Topology Data link layer the data link layer transforms the physical layer, a raw transmission facility, to a reliable link and is responsible for node to node delivery. the data link layer is concerned with the following: framing. physical addressing, each node has its unique address. flow control. access control. Layer 2 – the data link layer layer 2 of the osi model provides the following functions: •allows a device to access the network to send and receive messages • offers a physical address so a device’s data can be sent on the network •works with a device’s networking software when sending and receiving messages. 4 7 the ohio state university raj jain character stuffing delimit with dle stx or dle etx character flags insert ’dle’ before accidental ’dle’ in data remove stuffed character at destination fig 3 4 8 the ohio state university raj jain bit stuffing delimit with special bit pattern (bit flags) stuff bits if pattern appears in data remove stuffed bits at destination. Data link layer design issues • physical layer delivers bits of information to and from data link layer. the functions of data link layer are: 1. providing a well defined service interface to the network layer. 2. dealing with transmission errors. 3. regulating the flow of data so that slow receivers are not swamped by fast senders. • data.
04 Data Link Layer Pdf Osi Model Error Detection And Correction 4 7 the ohio state university raj jain character stuffing delimit with dle stx or dle etx character flags insert ’dle’ before accidental ’dle’ in data remove stuffed character at destination fig 3 4 8 the ohio state university raj jain bit stuffing delimit with special bit pattern (bit flags) stuff bits if pattern appears in data remove stuffed bits at destination. Data link layer design issues • physical layer delivers bits of information to and from data link layer. the functions of data link layer are: 1. providing a well defined service interface to the network layer. 2. dealing with transmission errors. 3. regulating the flow of data so that slow receivers are not swamped by fast senders. • data. Principles on which osi model was designed: a layer should be created where different level of abstraction is needed. each layer should perform a well defined function. the function of each layer should be chosen according to the internationally standardized protocols. The data link layer provides services to the network layer principal service is transferring data from the network layer of the source to the network layer of the destination machine. Explain the role of data link layer protocols in data transmission. describe how the data link layer prepares data for transmission on network media. describe the different types of media access control methods. identify several common logical network topologies and describe how the logical topology determines the media access control. The data link layer adds reliability to the physical layer by adding mechanisms to detect and retransmit damaged or lost frames. it also uses a mechanism to recognize duplicate frames.