Networking and Cabling Fundamentals

Importance of Cabling in Networking

• Cabling is crucial for all network infrastructure devices: routers, switches, wireless access points.
• Once installed, cabling is difficult to replace, emphasizing the need for correct installation.
• Even wireless networks need connections to cables at some point.

Common Cable Types

Twisted Pair Copper Cable

• Use: Standard for most wired Ethernet connections.
• Structure: Multiple wires twisted together within a single sheath.
  • Pairs often consist of transmit/receive signals, labeled as transmit+/- and receive+/-.
  • Twisting helps mitigate interference.
• Twist Rates: Different pairs have different twist rates, aiding in interference avoidance.

Coaxial Cable

• Structure: Single wire conductor with an insulator, shielding, and a jacket sharing a common axis.
• Common Usage: RG6 cables for Ethernet and internet connections (e.g., cable modems).

Twinaxial Cable (Twinax)

• Use: Common with 10 gigabit Ethernet, SFP+ interfaces.
• Advantages: Full-duplex communication over short distances (~5m), lower cost and latency compared to fiber optics.

Ethernet Standards and Cable Categories

• 802.3 Standards: Define minimum cable type and expected throughput for Ethernet standards.
• Cable Categories: E.g., Category 5, 6, 7.
  • Specifies minimum category required for specific Ethernet standards (e.g., Category 5 for 1000Base-T).

Plenum Spaces and Cable Installation

• Plenum Space: Area between drop ceiling and real ceiling, used for network cables, heat sensors, and power cables.
• Importance of Cable Type: In a shared airspace (plenum), correct cabling is crucial to prevent smoke/fumes distribution in a fire.

Plenum-Rated Cables

• Materials: Made from fluorinated ethylene polymer (FEP) or low smoke polyvinyl chloride (PVC).
• Benefits: Safer in fires compared to non-plenum-rated cables.
• Challenges: Less flexible, difficult to install in complex routes.

Cable Installation Guidance

• Ensure Correct Cabling: Check installation routes to use the appropriate cable type.
• Building Considerations: New or existing buildings may require different cabling approaches depending on the infrastructure.