3CX Media Server

Discussion in '3CX Phone System - General' started by TomBarker, Aug 4, 2013.

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  1. TomBarker

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    I have about 200 extensions most are Cisco SPA504g and using G711a. I have two sip trunks with two different providers, both using G711a as well. I have disabled "PBX Delivers Audio" on both, one allows Invites the other doesn't seem to as transfers to external numbers fail when enabled.

    Does this mean the 3CX server will simply pass through the audio from the trunk that supports invites straight to the handset without transcoding?

    and, will all audio from the trunk that doesn't support Invites be transcoded?

    Is there a way to tell which calls audio streams are being transcoded and which are being passed on as is.
     
  2. lneblett

    lneblett Well-Known Member

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    The best way to know for certain is to do a wireshark capture and look at the flow under telephony along with the actual data packets associated to the flow.

    Here is a description for the PBX delivers Audio aspect:
    http://www.3cx.com/blog/docs/media-server/
     
  3. TomBarker

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    Thanks for your reponse.

    If I take a wireshark capture and audio is in fact flowing through the PBX, how can I identify if it's passing through untouched (ie both parties are using the same codec, so no need to transcode) or whether it's being completely handled and transcoded?
     
  4. lneblett

    lneblett Well-Known Member

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    As indicated - look at the flow under the telephony tab. It shows the IP addresses and the "flow" of info from one IP to another. It will also show the type of info flowing.
     
  5. bardissi

    bardissi Member

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    Most providers wont be affected if PBX delivers audio.

    Actually due to NAT and Routers most likely not passing the audio through the PBX will be an issue as port ranges would be different and RTP ranges may not pass directly to the end destination.

    Also, the method in which the voip provider handles authentication (ip whitelisting vs user name / password) may also play a part of passing audio directly to the end site without PBX delivering audio.
     
  6. TomBarker

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    Thanks for your reply.

    Our 3CX server has a public IP and not behind a firewall. Our smaller sites connected to it via public internet without an issue. Our larger sites have a dedicated direct Ethernet link back to the server at our data centre.

    We are about to bring one of a largest sites on board which often has 100 calls going. As a result I'm going to have to upgrade the server used for our 3CX PBX. At the moment I have a DELL PowerEdge DS-M600-B (Quad Core Xeon Processor 2.50 Ghz, 4GB Ram).

    If I'm going to have 150 concurrent calls with PBX handling audio on all calls, what would be best option?

    I have the following options:
    Dell PowerEdge DS-M600-4 (2 x Quad-Core Xeon Processors E-5450 3.0Ghz, 16MB Ram)
    OR
    Dell PowerEdge DS-M610-4 (2 x Hex-Core Xeon Processors E-5645, 32MB Ram)

    Price isn't really a big issue, but if the Hex-Core is completely overboard, I may as well go the Quad-Core.

    Would be great to hear your thoughts.
     
  7. lneblett

    lneblett Well-Known Member

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    Take a look at the attached link.

    http://www.3cx.com/downloads/3CX_Phone_System_Operating_System_Specifications.pdf

    This should give you a pretty good idea as if worried, you can always jump to the next-up system to ease your concerns.
     
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