Network Cabling - CompTIA A+ 220-801: 2.2

The importance of cable

• Fundamental to network communication
• Incredibly important foundation
• Usually only get one good opportunity at architecting your cabling infrastructure
• Make it good!

• The vast majority of wireless communication uses cables
• Unless you're an amateur radio operator!

Fiber communications

• Transmission by light
• The visible spectrum
• No RF signal
• Very difficult to monitor or tap

• Signal slow to degrade
• Transmission over long distances

• Immune to radio interference
• There's no RF

 Multimode fiber

• Short-range communication
• Up to 2 km
• Inexpensive light source
• i.e., LED

Single-mode fiber

• Long-range communication
• Up to 100km without processing
• Expensive light source
• Laser beams

Twisted pair copper cabling

• Balanced pair operation
• Two wires with equal and opposite signals
• Transmit+. Transmit- / Receive+, Receive-
• The twist is the secret!
• Keeps a single wire constantly moving away from the interference
• The opposite signals are compared on the other end

• Pairs in the same cable have different twist rates

Shielded and unshielded cable

• STP (Shielded Twisted Pair)
• Additional shielding protects against interference
• Requires the use of an electrical ground
• Max distance follows the Ethernet standard

 

• UTP (Unshielded Twisted Pair)
•  No additional shielding
• The most common twister pair cabling
• Max distance follows the Ethernet standard

No plenum

Plenum

Plenum-rated cable

• Cable jacket
• Polyvinyl chloride (PVC) or fluorinated ethylene polymer (FEP)
• Plenum-rated cable may not be flexible
• May not have the same bend radius

• Worst-case planning
• Important concerns for any structure

• The riser
• Between-floor connections use riser cable
• Riser cable fire requirements aren't as strict as plenum cable

Coaxial cables

• Two or more forms share a common axis
• Used in older Ethernet networks
• 10BASES "Thicknet" RG-8/U (500m), 10BASE2 "Thinnet" RG-58 (185m)
• Used in television/digital cable
• Broadband internet
• RG-56

• Short distance video
• RG-59