Section 5: Media and Cabling Distribution

• Media


  Material used to transmit data over the network
• 3 categories of media

  Copper

  Fiber optic

  Wireless
• 3 Main Types of Copper Media

  Coaxial cables

  Twisted pair cables

  Serial cables
• Coax Cable Illustra

  
• Main places/examples to find Coax in modern networks: RG-6

  Commonly used by local cable companies to connect individual

  homes

  
• Main places/examples to find Coax in modern networks: RG-59


  This is going to carry composite video

  between two nearby devices or connect an outlet

  to a cable modem.

  The one connected to your wall, the common one
• Ways Coax Cables connect

  F type or BNC Type connectors

  Most today are F type, which is screw on

  BNC is old but still seen today in DoD or military contractors because they have not upgraded to F type yet
• Twinaxial Cable

  Newer and similar to coaxial cables but uses 2 inner conductors to carry the data instead of just 1
• twinaxial cable illustration

  
• Twinaxial cables are used for very short range,

  high speed connections between devices.
• Twinaxial cables offer speeds of 10 gigabits per second and it uses a lot less energy than traditional copper cables to achieve this level of speed
• Serial Cable

  Usually have a series of straight copper wires inside a single cable or plastic jacket

  DB-9 or DB-25 (RS-232)

  9-pin or 25-pin D-subminiature

  Used for asynchronous serial communications and connecting to

  an external modem

  
• Serial cables are very old and not commonly used in modern networks but may still come across them
• The most popular type of copper cable is the twisted pair
• twisted pair cable

  
• The twists in a twisted pair cable protect it from electromagnetic interference or EMI

  The more you have within an inch of the cable the better
• The more interference you have, the worse your data transmission rate is going to be, because you have to re transmit data more often

  This is why twists in the twisted pair cables are so important
• CAT Cables - general theme is that the higher the number, the higher the speed
• Types of twisted pair cabling:

  UTP - unshielded twisted pair

  STP - shielded twisted pair

  Metal Shielding from the elements, stp costs more

  UTP is all plastic, besides the thin copper in the pairs
• Unshielded twisted pair is more commonly used than shielded twisted pairs because of cost and ease of installation - it can bend easier
• Because of the metal shielding with STP cables they minimize EMI even more
• STP and UTP operate the same with the exception of EMI

  They both can go up to around 300 ft
• connector types associated with twisted pair cables:

  RJ45

  and

  RJ11

  The RJ45 is the most common used connector in networks

  
• RJ45 is used with data networks

  RJ11 is used with phone networks
• Bandwidth

  Theoretical measure of how much data could be transferred from a source to its destination
• Throughput

  Actual measure of how much data transferred from a source to its destination
• In real life, bandwidth and throughput are often used interchangeably, but there is a by definition difference in that throughput is measured and bandwidth is theoretical
• Straight Through Cable (Patch Cable) 


  Contains the exact same pinout on both ends of the cable

  
  

  Pin1 on 1 side goes straight on through to pin1 on the other side
• Data Terminal Equipment (DTE)


  "Endpoint" devices that connect to a piece of data communications equipment or DCE (e.g. laptops, desktops, servers, and routers)
• Data Communications Equipment (DCE)


  Includes things like switches, modems, hubs, and bridges
• Straight through cables are used to connect Endpoints to Comm equipment and vice versa

  DTE to DCE

  DCE to DTE
• Cross over cables are used to connect a terminal to a terminal (DTE to DTE)

  OR a communication equipment to another communication equipment (DCE to DCE)
• Crossover Cable


  Swaps the send and receive pins on the other end of the cable when the connector and its pinouts are created

  One end is 568A and the other is 568B
• For the exam remember that a switch to a switch connection requires a CROSSOVER cable
• Medium Dependent Interface Crossover (MDIX)


  An automated way to electronically simulate a crossover cable connector even if using a straight through patch cable

  Aka, in the modern world modern switches worrying about the type of cable is no longer a concern. But for the exam remember that if a switch does not support MDIX then they need a crossover cable to talk to another switch
• Plenum Cable

  A special coating put on a UTP or an STP cable that provides a fire retardant chemical layer to the outer insulating jacket

  
  

  Must be used if running cables somewhere you can not see, like behind walls or in ceilings
• 568B has this color scheme:

  1. Orange & white
  2. Orange
  3. Green & white
  4. Blue
  5. Blue & white
  6. Green
  7. Brown & white
  8. Brown

  I remember this by envisioning a scene:

  • I imagine a blue lake surrounded by green grass.Thus blue is in the middle (4&5) surrounded by green (3&6)
  • Above that is an orange sunset (1&2)
  • Below that is the brown dirt underground (7&8)
• 568A and B pinouts

  
• 568A has this color scheme:

  1. Green & white
  2. Green
  3. Orange & white
  4. Blue
  5. Blue & white
  6. Orange
  7. Brown & white
  8. Brown
• Non plenum rated cables also known as PVC can be used for something like a wall jack to a desktop