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Chương 8 - OSI Physical Layer

Explain the role of Physical layer protocols and services in supporting communication across data networks. | Chapter 8 - OSI Physical Layer CCNA Exploration 4.0 Objectives Explain the role of Physical layer protocols and services in supporting communication across data networks. Describe the role of signals used to represent bits as a frame is transported across the local media Describe the purpose of Physical layer signaling and encoding as they are used in networks Identify the basic characteristics of copper, fiber and wireless network media Describe common uses of copper, fiber and wireless network media Communication signals Physical Layer - Purpose The OSI Physical layer provides the means to transport across the network media the bits that make up a Data Link layer frame. This layer accepts a complete frame from the Data Link layer and encodes it as a series of signals that are transmitted onto the local media. The encoded bits that comprise a frame are received by either an end device or an intermediate device. Physical Layer - Purpose Physical layer elements for delivering of frames: A representation of bits on the media Encoding of data and control information Transmitter and receiver circuitry on the network devices The physical media and associated connectors At this stage of the communication process, the user data has been segmented by the Transport layer, placed into packets by the Network layer, and further encapsulated as frames by the Data Link layer. The purpose of the Physical layer is to create the electrical, optical, or microwave signal that represents the bits in each frame. These signals are then sent on the media one at a time. Circuitry: mạch điện, hệ thống mạch điện Physical Layer - Operation There are three basic forms of network media on which data is represented: Copper cable Fiber Wireless Physical Layer - Operation Identifying a Frame Encodes the bits into the signals for a particular medium Distinguish where one frame ends and the next frame begins. The Physical layer may add its own signals to indicate the beginning . | Chapter 8 - OSI Physical Layer CCNA Exploration 4.0 Objectives Explain the role of Physical layer protocols and services in supporting communication across data networks. Describe the role of signals used to represent bits as a frame is transported across the local media Describe the purpose of Physical layer signaling and encoding as they are used in networks Identify the basic characteristics of copper, fiber and wireless network media Describe common uses of copper, fiber and wireless network media Communication signals Physical Layer - Purpose The OSI Physical layer provides the means to transport across the network media the bits that make up a Data Link layer frame. This layer accepts a complete frame from the Data Link layer and encodes it as a series of signals that are transmitted onto the local media. The encoded bits that comprise a frame are received by either an end device or an intermediate device. Physical Layer - Purpose Physical layer elements for .