W3&4-2—chapter-04—Network Access part 2.pdf

Introduction to Networks Chapter 4: Network Access Part 2 4.2 Network Media Presentation_ID © 200 8 Cisco Systems, Inc. All righ ts reserved. Cisco Confidentia l 1 Purpose of the Physical Layer The Physical Layer Present...

Introduction to Networks Chapter 4: Network Access Part 2 4.2 Network Media Presentation_ID © 200 8 Cisco Systems, Inc. All righ ts reserved. Cisco Confidentia l 1 Purpose of the Physical Layer The Physical Layer Presentation_ID © 200 8 Cisco Systems, Inc. All righ ts reserved. Cisco Confidentia l 2 Purpose of the Physical Layer Physical Layer Media Presentation_ID © 200 8 Cisco Systems, Inc. All righ ts reserved. Cisco Confidentia l 3 Data can be analog or digital. Digital data refers to information that has discrete states. Digital data take on discrete values. Digital signals can have only a limited number of values. Analog data refers to information that is continuous; Analog data take on continuous values; Analog signals can have an infinite number of values in a range. Fundamental Principles of Layer 1 Bandwidth Bandwidth has two primary meanings: 1. Signal or Channel Bandwidth: The range of frequencies a signal or channel occupies, measured in hertz (Hz). (More formal use of the term) 2. Network Bandwidth: The maximum data transfer rate of a network connection, measured in bits per second (bps). (Informal use of the term) thousand million billion triillion Presentation_ID © 200 8 Cisco Systems, Inc. All righ ts reserved. Cisco Confidentia l 5  What is the name we give to actual data transfer rate of a network connection, measured in bits per second (bps), obtained over a network is called its throughput? Throughput Presentation_ID © 200 8 Cisco Systems, Inc. All righ ts reserved. Cisco Confidentia l 6 4.2 Network Media Presentation_ID © 200 8 Cisco Systems, Inc. All righ ts reserved. Cisco Confidentia l 7 Copper Cabling Characteristics of Copper Media Interference in copper media can occur due to electromagnetic radiation from nearby electrical devices, crosstalk from adjacent cables, or environmental factors like radio frequency interference. Presentation_ID © 200 8 Cisco Systems, Inc. All righ ts reserved. Cisco Confidentia l 8  Copper Cabling Copper Media Twisted pair cable Common with additional networking cable shielding to with twisted reduce pairs, lacking electromagnetic external interference. shielding. Unshielded Twisted Shielded Twisted Pair (UTP) Cable Pair (STP) Cable Coaxial Cable Cable with a central conductor, insulating layer, and shield for signal transmission. Presentation_ID © 200 8 Cisco Systems, Inc. All righ ts reserved. Cisco Confidentia l 9 Copper Cabling UTP Cable in more detail What’s a UTP cable again? Twisted pairs are twisted to reduce electromagnetic interference (EMI) and crosstalk between adjacent wires, enhancing signal integrity and transmission quality. Presentation_ID © 200 8 Cisco Systems, Inc. All righ ts reserved. Cisco Confidentia l 10 Copper Cabling STP Cable in more detail What’s an STP cable again? STP cables are less popular than UTP cables due to their higher cost, installation complexity requiring proper grounding, bulkiness, and because UTP cables provide sufficient performance for most environments without the need for additional shielding. Presentation_ID © 200 8 Cisco Systems, Inc. All righ ts reserved. Cisco Confidentia l 11 Copper Cabling Coaxial Cable Coaxial cable features a high-quality central copper conductor with superior shielding, providing enhanced protection against electromagnetic interference (EMI) and reduced signal loss compared to UTP and STP cables, making it ideal for high-frequency and long-distance data transmission. Presentation_ID © 200 8 Cisco Systems, Inc. All righ ts reserved. Cisco Confidentia l 12 Copper Cabling Cooper Media Safety Ensure cables are connected neatly and correctly to avoid faults and enable easy traceability. Grounding provides a safe path for electricity to flow back to the ground in case of a fault (e.g., a short circuit or equipment failure). If equipment is not properly grounded, metal parts can become energized, posing a risk of electric shock. Presentation_ID © 200 8 Cisco Systems, Inc. All righ ts reserved. Cisco Confidentia l 13 UTP Cabling Properties of UTP Cabling UTP cable does not use shielding to counter the effects of Electromagnetic Interference (EMI) and Radio Frequency Interference (RFI)*. Instead, cable designers have discovered that they can limit the negative effect of crosstalk by: ▪ Cancellation through twisting wires ▪ Varying the number of twists per wire pair * A subset of EMI that specifically occurs in the radio frequency (RF) range, which is generally considered to be between 20 kHz to 300 GHz. Presentation_ID © 200 8 Cisco Systems, Inc. All righ ts reserved. Cisco Confidentia l 14 UTP Cabling UTP Cabling Standards Data Transmission Speed: Cable categories are differentiated Cat 3: Up to 10 Mbps, suitable for voice communication. Cat 5: Supports up to 100 Mbps; Cat 5e supports up to 1 Gbps. by their data transmission speed, Cat 6: Supports up to 10 Gbps over shorter distances. frequency, shielding, and intended Cat 7: Supports 10 Gbps over longer distances. use. Frequency: Cat 3: Up to 16 MHz. Cat 5/5e: Up to 100 MHz. Cat 6: Up to 250 MHz. Cat 7: Up to 600 MHz. Shielding: Cat 3, 5, 5e, 6 (UTP): Unshielded, relying on twisted pairs to reduce interference. Cat 7 (ScTP): Shielded with individual pair and overall shielding to minimize electromagnetic interference. Intended Use: Cat 3: Obsolete, previously used for telephony and early Ethernet. Cat 5/5e: Common for standard Ethernet networks; Cat 5e for Gigabit Ethernet. Cat 6: Suitable for high-speed networks and applications requiring greater bandwidth. Cat 7: Ideal for high-performance networks needing superior shielding and speed. Presentation_ID © 200 8 Cisco Systems, Inc. All righ ts reserved. Cisco Confidentia l 15 UTP Cabling UTP Connectors The RJ-45 UTP plug (also known as a connector) is attached to the end of a UTP cable and contains eight pins that correspond to the eight individual wires within the UTP cable. The RJ-45 UTP socket (or jack) is a receptacle mounted on network devices (such as computers, routers, switches, or wall plates) that the RJ-45 plug is inserted into. It also has eight contacts that align with the pins of the plug to ensure proper electrical connection. Presentation_ID © 200 8 Cisco Systems, Inc. All righ ts reserved. Cisco Confidentia l 16 Purpose of the Physical Layer Physical Layer Standards Presentation_ID © 200 8 Cisco Systems, Inc. All righ ts reserved. Cisco Confidentia l 17 UTP Cabling Types of UTP Cable Presentation_ID © 200 8 Cisco Systems, Inc. All righ ts reserved. Cisco Confidentia l 18 Fiber Optic Cabling Properties of Fiber Optic Cabling Fiber-optic cabling is now being used in four types of industry: ▪ Enterprise Networks ▪ Fiber-to-the-home (FTTH) and Access Networks ▪ Long-Haul Networks ▪ Submarine Networks Presentation_ID © 200 8 Cisco Systems, Inc. All righ ts reserved. Cisco Confidentia l 19 Fiber Optic Cabling Fiber Media Cable Design Cross-section of a fiber optic cable showing key components: Core: The central part where light signals are transmitted. Cladding: Surrounds the core, reflecting light back into the core to maintain signal strength. Buffer: Protects the cladding and core from damage and provides additional strength. Strengthening Material: Adds structural support and protects against physical stress. Jacket: The outer layer that protects the cable from environmental damage and wear. Presentation_ID © 200 8 Cisco Systems, Inc. All righ ts reserved. Cisco Confidentia l 20 Fiber Optic Cabling Types of Fiber Media Presentation_ID © 200 8 Cisco Systems, Inc. All righ ts reserved. Cisco Confidentia l 21  Fiber Optic Cabling Network Fiber Connectors ST Connectors SC Connectors Straight Tip): Quick- (Subscriber release bayonet- Connector): Push- tyle (stick and twist) pull fiber optic fiber optic connectors. connectors. LC Connector Duplex (Lucent Multimode LC Connector): Connectors: Small form factor Paired LC fiber optic connectors for bi- connector with a directional latch. communication. Presentation_ID © 200 8 Cisco Systems, Inc. All righ ts reserved. Cisco Confidentia l 22 Fiber Optic Cabling Fiber versus Copper Implementation Issues Copper Media Fibre Optic Bandwidth Supported 10 Mbps – 10 Gbps 10 Mbps – 100 Gbps Relatively short Relatively High Distance (1 – 100 meters) (1 – 100,000 meters) High Immunity To EMI And RFI Low (Completely immune) High Immunity To Electrical Hazards Low (Completely immune) Media And Connector Costs Lowest Highest Installation Skills Required Lowest Highest Safety Precautions Lowest Highest Presentation_ID © 200 8 Cisco Systems, Inc. All righ ts reserved. Cisco Confidentia l 23 Wireless Media Types of Wireless Media Presentation_ID © 200 8 Cisco Systems, Inc. All righ ts reserved. Cisco Confidentia l 24 Wireless Media Properties of Wireless Media Wireless does have some areas of concern including: ▪ Coverage area ▪ Interference ▪ Security Presentation_ID © 200 8 Cisco Systems, Inc. All righ ts reserved. Cisco Confidentia l 25 Presentation_ID © 200 8 Cisco Systems, Inc. All righ ts reserved. 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