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  • 1.  Silence Supression

    Posted Feb 08, 2010 01:44 PM

    I am using PCxset on computers located in India. The NBX is in Connecticut.



    Once the network was set to use priority, EF class. then I noticed static and whoosing sounds in the silence between words.



    I removed silense suppression and these noise went away.



    Is silence suppression  recognized accross a WAN?



    Cisco routers are in use





  • 2.  RE: Silence Supression

    Posted Feb 08, 2010 05:09 PM

    Silence suppression should be off on all devices . Not sure why you would use it to begin with .





  • 3.  RE: Silence Supression

    Posted Feb 09, 2010 09:49 AM

    I have had silence suppression on since I started using VTL's.



    The book says it reduces packets by 40%.



    Why wouldn't I use it? or When should it be used?





  • 4.  RE: Silence Supression

    Posted Feb 09, 2010 10:48 AM

    Silence suppression has been used in the past to reduce a white noise that can show up on the voice . In over 9 years , I have not used it as it can cause issues . I am not sure what you would use it for , eg , reduce packets , but I can see it removing some of the packets . Compression can be used to reduce overhead on the packets . You can prob troubleshoot your network and find the root cause of why the change sin your settings caused the issue but again , I do not know of anyone that uses Silent Supression anymore !



    Page 501 of the manual states for a condition known as congestion , silence suppression would be used to remove some packets .



     





    You can reduce NBX system’s bandwidth



    requirements by enabling 



    “silence suppression,” but doing so



    compromises audio quality. NBX



    Telephones generate voice frames at



    regular intervals for the duration of



    a connection. These frames normally



    continue when no one is speaking.



    When silence suppression is enabled, the



    NBX system sends a “silence



    indicator” when the NBX Telephone



    senses the start of a silent period.



    When another NBX device receives this



    indicator, it inserts “white noise”



    until it receives the next frame that



    contains real voice. All subsequent



    “voiceless” frames are suppressed



    during the silent period. However,



    most telephone users will notice the



    difference between genuine silence



    and generated silence.



     





     



     



     



     



     



     



     



    This type of silence suppression applies to Layer 2 Ethernet transfers. At



    Layer 3, the ConneXtions software achieves a similar result by not



    sending empty packets during a silent period. The receiving ConneXtions



    gateway generates a silence indicator or sends frames filled with silence,



    depending on the silence suppression mode.



     



    Congestion





    Users notice congestion when audio “breaks up” during a call.



    Congestion can occur anywhere on the



    network, for example, at an



    overloaded LAN (local or remote), at an



    overloaded router or firewall, or



    within an overloaded internet. Because



    voice packets are only significant



    during a conversation, IP networks



    respond to congestion by discarding



    data packets they cannot accommodate.



    Resending or delaying packets is



    not an effective solution.



    At the local level, congestion symptoms can be subtle. For example,



    routers from different vendors can



    respond differently to congestion



    because of the way they prioritize their



    response to packet congestion.



    When considering communications



    problems, it is important to maintain



    reserve capacity and to use a systematic



    approach that considers the



    entire, end-to-end, connection.



    This message was edited by merlin on 2-9-10 @ 8:03 AM


  • 5.  RE: Silence Supression

    Posted Feb 09, 2010 01:04 PM

    ok.



    Silence suppression is off on all my units, including VTL's connections also.  Right?





  • 6.  RE: Silence Supression

    Posted Feb 09, 2010 01:12 PM

    yes , I would



    Then retest everything and I'm sure you will be happy with the results !



     





  • 7.  RE: Silence Supression

    Posted Feb 10, 2010 12:03 PM

    thank you!!





  • 8.  RE: Silence Supression

    Posted Feb 11, 2010 11:29 AM

    My Pleasure !



    Email / call / IM if needed !