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Voice Conferencing quality and Virtualization RRS feed

  • Question

  • Our OCS 2007 R2 Deployment is:

    OCS 2007 R2 Standard
    OCS 2007 R2 Mediation (Connecting to/from Cisco Call Manager Express)
    OCS 2007 R2 Edge Server

    All three are Virtualized inside VMware ESX.  I know this isn't supported but our resources are stretched.  We do not use Enterprise Voice, it's mainly used for IM and LiveMeeting.    However, one thing we use a lot of is Voice Conferencing and have found the Conference Audio quality to be average, at best.  It's very very choppy and can make a group chat unusable.

    Cisco Call manager is routing xxxx into OCS to handing the conferencing.  No other voice is used.

    My question is, I am able to migrate one of the Servers from Virtual to Physical.   Which server should I migrate to Physical to sustain the best audio quality?  

    The Standard Edition Server or the Mediation Server?  I don't really have the option to do both.

    Thanks
    Friday, October 9, 2009 1:59 AM

Answers

  • Since all callers are PSTN (even internal users) then I'd look at moving the Mediation Server to the physical role.  But since your current ESX server is hihgly loaded, then using that second physical host for ESX and moving both OCS FE and Mediation guest to it would help dedicate a lot more resources to those two guests.

    Either approach should improve your user experience.


    Jeff Schertz, PointBridge | MVP | MCITP: Enterprise Messaging | MCTS: OCS
    • Proposed as answer by Gavin-ZhangModerator Monday, October 12, 2009 2:40 PM
    • Marked as answer by Matty_C Thursday, October 15, 2009 8:01 AM
    Friday, October 9, 2009 2:05 PM
    Moderator

All replies

  • Well that depends what your usage is...

    Are you using a lot of PSTN clients on the Dial-In conference?
    Are most of the users connect with Communicator Client?

    Maybe the easiest way to test is to setup a new Mediation Server on the physical machine and route all traffic through this new server.
    Then check the audio quality.

    But my guess is that you may need to have both Front-End & Mediation server as a physical server
    Mediation Server transcodes the audio streams to G7.11
    Front-End mixes the different audio streams to one stream
    They both need enough CPU power to do their work

    Have you configured dedicated resources for the OCS machines in VMWare?
    That may also help as you give a dedicated physical CPU to one Virtual Machine.


    - Belgian Unified Communications Community : http://www.pro-exchange.be -
    Friday, October 9, 2009 11:15 AM
  • If you can only move one guest to a physical host that will mostly depend on which endpoints you are supporting more of, OCS or PBX/PSTN callers, into Audio Conferences.  The big difference on how the Mediation server CPU is impacted is what codec is used end-to-end.  In a healthy network with little latency calls from the PBX/PSTN into the conferencing service will be G.711 from end-to-end, RTA is NOT used unless network conditions are such that the Mediation server sees fit to use the dynamic codec, which would then put a higher load on the Mediation server as it transcodes from G.711 to RTA.

    Another idea is if your current ESX server is hosting many virtual guests (other than just the 3 OCS guests) you could setup another ESX server dedicated to just the FE and Mediation servers, so that only those two guests share a single host.  But if your current ESX server only has the 3 OCS guests than that isn't gaining you much (Edge Server would use the least processing power).
    Jeff Schertz, PointBridge | MVP | MCITP: Enterprise Messaging | MCTS: OCS
    Friday, October 9, 2009 12:40 PM
    Moderator
  • The current ESX servers share a high workload with 25+ other hosts.  I will look into giving a dedicated CPU to each, although I don't know if it's possible in ESXi.

    *All* callers are through the PBX.   No one uses OCS internally for Voice.  Yes we have it enabled to allow users to PSTN authenticate, but everyone comes in PSTN externally into Call Manager then into OCS, or VoIP from Call Manager then OCS.

    Network is top notch, so I assume G.711 is used throughout and not RTA.
    Friday, October 9, 2009 1:43 PM
  • Since all callers are PSTN (even internal users) then I'd look at moving the Mediation Server to the physical role.  But since your current ESX server is hihgly loaded, then using that second physical host for ESX and moving both OCS FE and Mediation guest to it would help dedicate a lot more resources to those two guests.

    Either approach should improve your user experience.


    Jeff Schertz, PointBridge | MVP | MCITP: Enterprise Messaging | MCTS: OCS
    • Proposed as answer by Gavin-ZhangModerator Monday, October 12, 2009 2:40 PM
    • Marked as answer by Matty_C Thursday, October 15, 2009 8:01 AM
    Friday, October 9, 2009 2:05 PM
    Moderator
  • Hi
    Jeff gave a good suggestion.
    Do you have other issue, you can update it.

    Regards!
    Thursday, October 15, 2009 7:45 AM
    Moderator
  • Thanks for clarifying.

    I ended up using your suggesting and keeping it as a VM, but moving it onto a ESX server that doesn't run any other Guests.

    This saved me from having to convert it from Virtual2Physical (which is hard/annoying and/or impossible).  But still get dedicated resources.

    So far it's drastically improved voice quality.  But only time will tell if eventually it'll need true CPU.


    ESX also has CPU binding stuff which allows me to dedicate CPU's to a guest, which may also help here.
    Thursday, October 15, 2009 8:02 AM