Podcast
Questions and Answers
Which type of fiber-optic cable is best suited for very long distances?
Which type of fiber-optic cable is best suited for very long distances?
What is a significant drawback of wireless media compared to wired connections?
What is a significant drawback of wireless media compared to wired connections?
What is the primary purpose of NICs in the Physical Layer?
What is the primary purpose of NICs in the Physical Layer?
Which cable type is typically used for connecting devices in a straight-through configuration?
Which cable type is typically used for connecting devices in a straight-through configuration?
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What category of twisted pair cable is known for the best performance in terms of data speeds?
What category of twisted pair cable is known for the best performance in terms of data speeds?
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In the context of data transmission, what does throughput refer to?
In the context of data transmission, what does throughput refer to?
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What is one of the common standards for wireless local area networks (WLAN)?
What is one of the common standards for wireless local area networks (WLAN)?
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Which factor can contribute to signal attenuation in copper media?
Which factor can contribute to signal attenuation in copper media?
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Study Notes
OSI Physical Layer
- The lowest layer, responsible for converting bits into signals, and sending them across the media (electrical, light, or radio waves).
- Includes hardware like network interface cards (NICs), cables, connectors, transmitters, and receivers.
- Standards created by groups (IEEE, TIA/EIA, ISO, ANSI) ensure interoperability of physical hardware.
Wired Connections
- Use copper cables (e.g., Ethernet connections to a switch/router) or fiber-optic cables.
Copper Media (Cables)
- Unshielded Twisted Pair (UTP): Most common LAN cabling. Pairs of wires are twisted to reduce crosstalk. RJ-45 connectors typical. Categories (e.g., Cat5, Cat5e, Cat6) relate to data speed and interference reduction.
- Shielded Twisted Pair (STP): Similar to UTP but each pair or all wires are wrapped in foil/braid for better noise protection. More expensive.
- Coaxial Cable: Used less commonly in modern LANs, features a copper conductor with heavy shielding.
Copper Issues
- EMI/RFI: Electromagnetic/Radio Frequency Interference.
- Crosstalk: Signal interference within the cable.
- Signal Attenuation: Loss of signal strength over distance.
Cable Types
- Straight-Through: Used for host-to-switch or switch-to-router connections.
- Crossover: Used for switch-to-switch or host-to-host connections (auto-MDIX typically used today).
Fiber-Optic Media
- Transmits data as light signals.
- Has long distances, high bandwidth, and resistance to EMI/RFI.
- Single-Mode Fiber (SMF): Very thin core, laser light for very long distances.
- Multimode Fiber (MMF): Thicker core, LEDs for shorter distances (e.g., within a building).
- Includes connectors (e.g., ST, SC, LC).
- More expensive than copper, usually used for network backbones or between buildings.
Wireless Media
- Uses radio waves or microwave signals.
- Common WLAN standards include IEEE 802.11 (Wi-Fi), Bluetooth, and Zigbee.
- Benefits: Mobility, no cables needed.
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Limitations:
- Coverage: Walls/obstacles reduce signal strength.
- Interference: Other devices, microwaves.
- Security: Requires strong security (WPA2/WPA3).
- Shared Medium: Half-duplex can slow down with many users.
Bandwidth, Throughput, and Goodput
- Bandwidth: Maximum capacity of the medium (e.g., Mbps, Gbps).
- Throughput: Actual data rate achieved (usually lower than bandwidth).
- Goodput: Actual usable data rate after overhead (is the lowest of the three).
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Description
Test your knowledge on the OSI Physical Layer, focusing on its role in converting bits into signals and the various types of wired connections. Explore details about copper media, including UTP and STP cables, and standards for interoperability. This quiz is perfect for networking enthusiasts looking to solidify their understanding of foundational concepts.
