Networking Concepts: Ethernet and Media Types

Ethernet Speed and Throughput

• Ethernet speeds include 10Mb/s and 100Mb/s, with differences based on bits transmitted per second.
• Throughput is the measure of bits transferred over time, often lower than specified bandwidth due to various factors like traffic amount and latency from network devices.
• Goodput represents the effective throughput after accounting for traffic overhead, such as session establishment and acknowledgments.

Types of Physical Media

• Various interfaces and ports are utilized in network devices, particularly in routers.

Copper Cabling

• Copper cables transmit data as electrical pulses; however, the signal deteriorates with distance (attenuation).
• Strict distance limitations exist for all copper media, which are vulnerable to electromagnetic (EMI) and radio frequency interference (RFI).
• Crosstalk occurs when electrical or magnetic fields from one wire disturb signals in an adjacent wire; it can be mitigated by twisting wire pairs.

Unshielded Twisted-Pair (UTP) Cable

• UTP is the most common networking medium, terminated with RJ-45 connectors for connecting network hosts to devices like switches.
• It consists of four twisted pairs of wires to protect against interference and reduce signal attenuation, making it immune to EMI and RFI.

Fiber Optic Cabling

• Encodes bits on glass fibers using light pulses, offering superior transmission capabilities compared to copper.
• Composed of various layers: jacket (protection), strengthening material (prevents stretching), buffer (shields core), cladding (reflects light), and core (transmits light).

Fiber-Optic Connectors

• Includes Straight-Tip (ST), Subscriber (SC), Lucent (LC), and Duplex Multimode LC connectors, facilitating optical fiber connections.
• Requires fiber patch cords for interconnecting devices; specific color jackets indicate single-mode (yellow) and multimode (orange/aqua) compatibility.

Fiber Testing and Issues

• Termination and splicing of fiber-optic cabling require specialized training and can lead to errors like misalignment, end gap, or poor end finish.
• Optical Time Domain Reflectometer (OTDR) is used for testing fiber integrity; a simple flashlight test can check individual segments.

Wireless Media

• Wireless technologies transmit data using electromagnetic signals, often utilizing radio or microwave frequencies.

WAN Topologies

• Physical point-to-point topology features direct communication between nodes without intermediate devices.
• Logical point-to-point topology allows for physical node connections via various intermediate devices, creating virtual circuits.

LAN Topologies

• Various physical LAN topologies include:
  • Star: all end devices connected to a central switch.
  • Extended Star: interconnects multiple star topologies.
  • Bus: legacy system where devices are chained with termination at both ends, typically using coax cables.
  • Ring: each device connects to two others, forming a circle without needing termination.

Data Link Frame

• Data link frames contain source and destination MAC addresses corresponding to the network interface cards (NICs).
• Layer 2 protocols, such as Ethernet, 802.11 Wireless, and PPP, are crucial for defining topology technology.

Conclusion of Networking Fundamentals

• Understanding physical layer protocols supports network communication.
• Basic networks can be built using appropriate media.
• The data link layer is essential for facilitating communications, utilizing various access control techniques and topologies.