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  • PoE switching

    Hi all,

    we use a LG-Nortel digital telephone system.
    We have 3 no. ES-2024G switches, uplinked to each other via one of the gigabit ports (no SFP).
    Just about every port is being used to power the desk handsets, however each handset has a passthrough port which then connects to each users pc, giving them their network connection (we don't have enough floor ports available and adding more is not an option).
    LG assure me that it's purely a passthrough coupler and that no speed drops should happen.
    Ok so far.
    Having looked at the manual, it says this:
    "The first six ports on the switch can provide up to 30 W of power to a connected device. The switch can supply 15.4 W simultaneously to 12 PoE devices among 24 Gigabit Ethernet ports, or 30 W simultanesously to six connected PoE devices. The total power can not exceed 185 W PoE power budget."
    Now, i don't really understand the power reqs etc, but all the pc's connected to the swtiches via the deskphones will either have 10/100 or gigabit lan cards in.
    Can anyone see any reason why we shouldn't operate this way?
    Of course, if the phone system needs to be rebooted then yes, we'll lose network connectivity for that short space of time, but other than that...?
    Could the lower power to the remaining ports not be sufficieint to provide gigabit speeds?
    I've personally performed a lan test on my pc using the phone passthrough and connecting it via the floor box, both hit 11MBps (so almost maxing 100Mbit), which aint too good tbh, but they are at least consistent.

    Any advice would be appreciated, thanks.

  • #2
    Re: PoE switching

    Originally posted by k.jacko View Post
    Can anyone see any reason why we shouldn't operate this way?
    You should be fine as long as you dont exceed the power requirements of the switch. You really would only will experience problems if you had a network where everyone was receiving calls or on calls on their phones all at the same time (unlikely scenario). That is when the phones use the most power.

    Of course, if the phone system needs to be rebooted then yes, we'll lose network connectivity for that short space of time, but other than that...?
    Could the lower power to the remaining ports not be sufficieint to provide gigabit speeds?
    The power really has nothing to do with the port speed.

    I've personally performed a lan test on my pc using the phone passthrough and connecting it via the floor box, both hit 11MBps (so almost maxing 100Mbit), which aint too good tbh, but they are at least consistent.
    Your LG phones are most likley 10/100 ports so anything connected on the LAN port of the phone will not get Gb speeds. If you are directly connected to the switch and your PC or laptop has a Gig NIC, you should see higher throughput.

    hth,
    ss

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    • #3
      Re: PoE switching

      Originally posted by sabbasaun View Post
      Your LG phones are most likley 10/100 ports so anything connected on the LAN port of the phone will not get Gb speeds. If you are directly connected to the switch and your PC or laptop has a Gig NIC, you should see higher throughput.
      Thanks for the reply, LG have assured us that the network port on the phone is purely a pass-through adaptor and not a speed-rated nic itself.

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      • #4
        Re: PoE switching

        There is a switch in the telephone. You connect 2 network devices to a single switch port. Than is not possible without a switch.
        gerth

        MCITP sa, ea & va, [email protected]

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        • #5
          Re: PoE switching

          Originally posted by gerth View Post
          There is a switch in the telephone. You connect 2 network devices to a single switch port. Than is not possible without a switch.
          err.....ok.
          Either way they say it won't hinder gigabit speed throughput.

          Thanks.

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          • #6
            Re: PoE switching

            I just checked a recent lg ip telephone. According to the datasheet it has a 10/100 switch installed. What type of phone are you using?
            Last edited by gerth; 29th July 2011, 20:39. Reason: typo
            gerth

            MCITP sa, ea & va, [email protected]

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