CCNA 1.7: Select the appropriate cabling type based on implementation requirements


Understand cabling types based on their implementation.  In other words, certain cables are used for certain situations.  Use the wrong cable and it's not going to work.  Unless you get saved by the smarts in the device.  Most network devices these days have an autodetect function, which understands if there is a straight-through or crossover cable connected and adjusts accordingly.  Still, you should know the right way to do things.


Study Notes:

Crossover cable

  • Use when connecting like devices together
  • Switch to Switch (autodetect on most switches will work with straight-through cables, but crossover is the correct choice)
  • Router to Router
  • Router to PC
  • 10Base-T and 100Base-T UTP (1 to 3 and 2 to 6) (UTP = Unshielded Twisted Pair)
  • For a crossover, use 568A on one end and 568B on the other end


EIA/TIA 568B Standard EIA/TIA 568A Standard
1 white-orange Related image 1 white-green
2 orange 2 green
3 white-green 3 white-orange
4 blue 4 blue
5 white-blue 5 white-blue
6 green 6 orange
7 white-brown 7 white-brown
8 brown 8 brown


1000Base-T UTP

  • uses all four cable pairs for simultaneous transmission in both directions
  • no dedicated transmit and receive pairs, and consequently, crossover cables are never required
  • the physical medium attachment sublayer (PMA) provides identification of each pair and usually continues to work even over cable where the pairs are unusually swapped or crossed.


Straight-through cable

  • Use when connecting unlike devices together
  • Also known as a patch cable
  • Switch to PC
  • Router to Switch
  • For a straight-through, use 568B on both ends
EIA/TIA 568B Standard EIA/TIA 568B Standard
1 white-orange Image result for straight through cable 1 white-orange
2 orange 2 orange
3 white-green 3 white-green
4 blue 4 blue
5 white-blue 5 white-blue
6 green 6 green
7 white-brown 7 white-brown
8 brown 8 brown


Rollover cable

  • Literally roll the cable over to make the other end
  • Can be used to connect a host EIA-TIA 232 interface to a router console serial COM port
EIA/TIA 568A Standard EIA/TIA 568A (reversed)
1 white-green Image result for rollover cable wiring 1 brown
2 green 2 white-brown
3 white-orange 3 orange
4 blue 4 white-blue
5 white-blue 5 blue
6 orange 6 white-orange
7 white-brown 7 green
8 brown 8 white-green



  • Very long distances, but seeing it more on the LAN now as well
  • Made up of Core, Cladding and Buffer.  Cladding is industry standard at 125m
  • As a point of reference, a human hair is 50 microns
  • Single mode fiber: tighter cladding = smaller core, one mode of light propagates
  • Multi-mode fiber: looser, larger core allows multiple light particles, less distance


PacketTracer Lab: CCNA-1.7-Select-the-appropriate-cabling-type-based-on-implementation-requirements.pkt

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  1. soham jana
    soham jana
    October 21, 2018 at 2:21 am

    Hey Joe, you have made an amazing website and a huge contribution to students like me. But there are some mistakes: 1. cross-over cable, bullet 5, 1 to 3 and 2 to 6 2. straight-through cable, bullet 5, straight-through cable. Consider revising it once.

    • Joe Barger (CCNP/CCDP)
      Joe Barger (CCNP/CCDP) • Post Author •
      October 21, 2018 at 9:27 pm

      Thank you for catching those. They have been fixed.

  2. Craig Dupont
    Craig Dupont
    November 7, 2018 at 2:41 pm

    Hello Joe, I truly appreciate your website are there any plans for creating something for CCNP and CCDP ?

    • Joe Barger (CCNP/CCDP)
      Joe Barger (CCNP/CCDP) • Post Author •
      November 7, 2018 at 10:39 pm

      Hey Craig, I would definitely like to expand this format to other certs including the CCNP and CCDP. I’m not sure when that will happen once I complete the CCNA topics. While I really enjoy putting the labs together it seems a lot of people are finding value in the combination of study notes and labs.

  3. Craig Dupont
    Craig Dupont
    November 8, 2018 at 12:17 am

    Thanks for getting back to me Joe and yes I am one of those people.

  4. Dani Tene
    Dani Tene
    May 5, 2019 at 10:56 am

    hi, for straight through cable, can you use also 568A standard?

    • Joe Barger (CCNP/CCDP)
      Joe Barger (CCNP/CCDP) • Post Author •
      May 5, 2019 at 12:36 pm

      Yes you definitely can. Any pinouts that are the same on both ends will work.

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