Question about A/V, Web Conferencing and VM's... RRS feed

  • Question

  • Here's my current topology:  1 OCS access edge server and 1 OCS standard front end server.  Not using a director. 
    Currently, we're only using IM functionality with internal/external connectivity.  As was the case with our LCS 2005 infrastructure, both servers are running as virtual machines (esx) in a production environment (not recommended, I know, but functional nonetheless).  We've never had an issue with said scenario.

    Now I want to enable the A/V and Web Conferencing roles.  For this, I've been allocated a physical server.  My question is this.  Where will the majority of the load be placed - what would be the bottleneck?  Should I configure the physical server as a new access edge server, replacing the existing edge server and add the new roles to it?  Or should I introduce it into our topology as a new front end server?

    Wednesday, March 26, 2008 9:33 PM

All replies

  • Do the specifications indicate that the physical server will outperform the virtual machines?  Although virtual machines are not supported for OCS, they can often run just as well or better than physical machines.  We run our front-end and director on ESX VMs and our consolidated edge on a physical server (simply because there was not an ESX host in the DMZ).  We have had no issues yet.

    Do you have any estimates of host many simultaneous conferences you will support and how many simultaneous conferencing users?  Do you have any specifications on how many voice and video calls will traverse the A/V Edge?  Those factors will likely make the decision.


    Thursday, March 27, 2008 2:48 AM
  • I've read several posts indicating that it's officially an unsupported best-effort scenario to use virtual machines in an OCS infrastructure.

    It's a little difficult to project peak usage.  Consider that we only have about 800 users.  Just to speculate, if I have AV and Web Conferencing feature enabled for internal/external use, where would the majority of strain/throughput be?  On the edge or front end?  Or it it equal?  I realize that if the majority of conferencing is internal then I should use the physical as my front end....
    Thursday, March 27, 2008 6:01 PM
  • I agree that the VM scenario is unsupported; I'm just saying it works for us.


    The answer to your question still depends on the type of use and location of your users.  The more users that connect externally or communicate with external partners, the heavier the usage will be on the edge.  If you do not expect many users to connect from the internet, join conferences from the internet or communicate to federated users, then I would devote my resources to the Front-end server.


    Thursday, March 27, 2008 8:51 PM
  • I agree with James that the answer to your question really depends on user type and location.  Seeing how A/V & Conferencing will be new to your users, you should consult the OCS Planning Guide and OCS Edge Deployment Guide (http://technet.microsoft.com/en-us/library/bb676082.aspx) to help you esitmate your initial capacity. 


    Since you have no metrics to base usage on, you will have to make a calulated guess, monitor performance over a 3-6 month period and tune your configuration as needed.  Generally speaking, the A/V Edge requires the most bandwidth and throughput...that's why the A/V Edge Role is placed on a seperate box in a Single-Site Edge configuration.  If the majority of your traffic (IM, Conferencing, A/V) is internal, then you should put the beefy box inside and leave the DMZ as is...just add the additional Edge roles.   


    A couple of things I did not see any mention of was a Mediation Server, a gateway, or hybrid gateway solution to provide the rest of the OCS puzzle.  Also, how do you intend to publish the ABS, DL Expansion, and Meeting content?  Typically, that is done via ISA or other 3rd Party Proxy server.  Also, make sure you have a publically routable IP for the A/V Egde role.




    Tuesday, April 1, 2008 5:25 AM
  • Hi,

    I can speak from experience that the minute you virtualize a server that handles voice or video traffic, you will see a big-time degredation in those services: mediation & A/V specifically. Virtualizing other roles doesn't seem to be as big of a deal.


    BTW - this is not unique to MS... you will notice that no vendor (at least any that I've seen) supports virtualization for any device that handles A/V streams. The processing power and the time-sensitivity of voice and video packets makes voice a bad application to use VMs with.


    We virtualized our mediation server while rebuilding the physical box - it couldn't really even handle 1 or 2 calls without really sounding terrible.


    So my advice: stay away from VMs with any OCS server that handles real-time streams like the mediation or A/V roles.






    Sunday, April 6, 2008 1:51 PM