What would 3cx require in this Scenario?

Discussion in '3CX Phone System - General' started by ipSkillz, Mar 26, 2007.

  1. ipSkillz

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    Hi all.

    What would 3cx require in the following scenario,

    10 employees, in seperate offices with seperate internet connections.

    1 3cx call server on say 1.5mbit to 8mbit connection.

    Will the server itself be providing all of the bandwidth for all incoming calls to each of the employees?

    Can somone help me out here? :lol:

    Thanks in advance all.
     
  2. Anonymous

    Anonymous Guest

    Codec Codec Bit Rate (Kbps)
    G711 64
    G.729 8
    G.726 32/24

    G711u/a - Requires 64+Kbps (inbound and outbound) continuous data stream for a quality call, plus the SIP signal so to have a good conversation you need minimal 128Kbps per conversation.

    So 10 concurrent users is 10*128Kbps that is approx 1.5Mbps to be save (give and take the overhead for protocols).

    Now in your scenario you want hmmm ain't gonna work. :evil:

    Your inflow is ok but your outflow on the plan you outline is only 385 so that will support approx 5 outbound calls.

    Unless you can spread the extensions across multiple offices. For example have each office have their own 3cx to function as a "hub" and do a bit multicasting or something like that.

    All employees into one is ok but the return traffic might be an issue.

    Henk.
     
  3. ipSkillz

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    Hmm ok so multicasting.

    The idea was to give each of the emlployees a sipphone to work from thier remote location. I could jack the server up to 24 mbit but the upload would still remain at 1mbit ... so I guess it's a fairly defunct idea.

    I think I get your point though.

    Perhaps the employee could run a pbx to accept streams as you've suggested, essentially linking and receiving the call streams from the 3cx, and then have the employees pbx drop the 3cx connection after they''ve received the initial "joint".

    I have used this configuration under other pbx software, not sure where 3cx stands in a position like this.

    Morning itfarmer :)
     
  4. archie

    archie Well-Known Member
    3CX Staff

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    We're not consuming more bandwidth than others do. :lol:
     
  5. Anonymous

    Anonymous Guest

    :lol:

    I would be surprised if that was the case.

    See what the numbers i mentioned are based upon the requirement stated.

    10
    But you might actually find that not all the 10 employees are in a conference at the same time so the traffic will be less :).

    Not sure how the "silent" traffic pans out (might have a look at that) if no voice is transported is the bandwidth requirement still there?

    Most phone conversations are multiplex however most of the time only one person is talking............ well in general that is the case.
     
  6. Costas3CX

    Costas3CX New Member

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    For example:
    G711 which is the codec we use mostly has a fixed bit rate.
    GSM which we also use has a fixed bit rate.

    Even if there is silence on the channel the bitrate is the same. To detect silence you need special algorithms. Some codecs do this but not very succesfully. Studies in the ITU showed that changes between narrow-band and wide-band voice codecs can be disturbing.
     
  7. Nick Galea

    Nick Galea Site Admin

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    It would seem that you have enough bandwidth for that scenario - your internet links are very good and there are only a few people, so that should work fine. You could start off with G711 codec (requires 64k plus overhead) and if necessary go down to GSM codec (13k plus overhead). Note that we do not support G729 or G726 since these codecs have royalties.
     

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