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Network cable lengths

Discussion in 'Networks' started by twizzle, Mar 21, 2007.

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  1. twizzle

    twizzle Gigabyte Poster

    Does anyone kow of a piece of equipment that can simulate different lengths of ethernet cable for network testing?

    I need to producce a test procedure that test our equipment on a network and i need to find out how long a cable run before it starts to fail. I also need to test this through various swithces and routers so would like a device to adjust cable lengths rather than having to keep changing the cables to set lengths.
    Certifications: Comptia A+, N+, MS 70-271, 70-272
    WIP: Being a BILB,
  2. simongrahamuk
    Honorary Member

    simongrahamuk Hmmmmmmm?

    Don't think that such a thing exists mate.

    You could always just accept what the standards people say is the max length and stay under it. :blink
  3. garyb

    garyb Byte Poster

    WIP: MCSA 2003
  4. Arroryn
    Honorary Member

    Arroryn we're all dooooooomed

    I don't know of any physical equipment, but my other half uses AutoCAD and AMTech for his drawing; he is a sparky, and this simulates circuits and the continuity of such when the design is done; perhaps an AutoCAD(esque) package could do the same for networking?
    Certifications: A+, N+, MCDST, 70-410, 70-411
    WIP: Modern Languages BA
  5. tripwire45
    Honorary Member

    tripwire45 Zettabyte Poster

    I'd have to go along with Si. I've never seen a network engineer design a system that way. The reason we memorize all that stuff about cable lengths for the Network+ exam is so we won't have to do those sorts of tests.
    Certifications: A+ and Network+
  6. BosonMichael
    Highly Decorated Member Award

    BosonMichael Yottabyte Poster

    Agreed - that sort of thing doesn't exist. Sure, you might be able to get a longer distance out of a cable length than the recommended maximum... but you might not. Depends on interference, quality of cable, ability of the endpoints to clearly "hear" the signal, etc. Run your cable past an electrical source of interference and you won't come close to the max length.

    Simply take reasonable efforts - stay under the maximum cable length and avoid sources of EMI on your cable runs.
    Certifications: CISSP, MCSE+I, MCSE: Security, MCSE: Messaging, MCDST, MCDBA, MCTS, OCP, CCNP, CCDP, CCNA Security, CCNA Voice, CNE, SCSA, Security+, Linux+, Server+, Network+, A+
    WIP: Just about everything!
  7. AJ

    AJ 01000001 01100100 01101101 01101001 01101110 Administrator

    Saying that I do know that Telecoms engineers have a piece of kit to see where a cable has broken, giving you the lengh of a piece of cable. However, these bits of kit are very specialised and probably some considerable amount of money and I've no-idea what they are called.
    Certifications: MCSE, MCSA (messaging), ITIL Foundation v3
    WIP: Breathing in and out, but not out and in, that's just wrong
  8. Spice_Weasel

    Spice_Weasel Kilobyte Poster

    Called a TDR - time domain reflectometer.

    BTW a number of Cisco switches (and some from other manufacturers) have a built in TDR. For example, on a 2960 you can use the built in TDR on any switchport, it will return the length of each of the 4 pairs in the cable, and the staus of the pair. Very handy - sometimes use it to check the length of an odd spool of cable or an unknown run.

    Certifications: CCNA, CCNP, CCIP, JNCIA-ER, JNCIS-ER,MCP

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