Help with OCS Server topology RRS feed

  • Question

  • Hi all

    Hopefully this question has not been answered before, I could not see it on a quick search.


    We are looking at deploying OCS 2007 across 2 physical sites that are part of the same AD forest (single domain) with a 2Mb point to point circuit between sites.  If High Availability is not a concern, what would my likely server topology be?


    Each site would require IM and presence indication of users at both sites.  Also we would need the ability to web and a/v conference between sites. Most of the conferencing would be done within each site though.  We would also see users wanting to a/v conference in from home across a VPN.  Each site has it's own VPN termination points.


    Any help would be greatly appreciated.  I have read through the MS Planning document but I really cant see a valid config for 2 site communication (only larger multi-site configs).  Is this possible without the bells and whistles of Enterprise pools?  I'd like to keep the physical server deployment to as minimum as possible,


    Many Thanks


    Tuesday, November 25, 2008 12:55 PM

All replies

  • Hi,


    Well it depends on the number of users and how much cross-site access you can afford on your network links. There is no hard dependency for OCS on Active Directory sites so you can deploy everything in a single AD Site and have users from across the domain connect to it but it does mean you will have IM, PSOM and RTP traffic going across the WAN which if in high numbers can saturate your WAN link.


    So if you want to avoid this and have each user connect to their own server inside the site you could deploy 2 pools. Note that a pool can be a single OCS Standard Edition (SE) server if you don't want High Availability. Once you have a pool in each AD site you can start homing users on their own pool. To allow for automatic configuration I would recommend you deploy a OCS Director Role in ONE of the 2 sites which automatically redirects the users to their approperiate servers. Although the traffic from within your enterprise towards the director will go towards a single site and as such impact the WAN we only have this traffic for the SIP Dialog which is very small compared to PSOM and RTP traffic which will go directly to the SE server.


    I hope this helps you further....



    Tonino Bruno

    Tuesday, November 25, 2008 2:06 PM
  • If you do A/V and Web conferencing and you are going to do Audio & Video & Roundtable then the traffic will be high to all your endpoints, if you need multiple people in remote sites to connect to same conference then multiple streams will go over the WAN


    368 Kbits for Audio and Video receive

    688 Kbits for Audio, Video and RoundTable receive


    Still not talking about sending audio or video because this would send bits over the WAN to the other side aswell

    And what to say about latency and congestion, the codec can do a lot of tweaking itself but when the pipe is full you will not see good experience


    So if you would have just a few joining you can easily get to 2Mbps and then we are not talking about other applications that also travel the WAN Link


    If as you say most Web and A/V conferencing will be performed within the sites and not between sites then you should put a pool in each site


    A pool will not help you in the scenario when a Web A/V conference is held between sites then traffic will always go over the WAN




    Wednesday, November 26, 2008 12:07 AM
  • Many thanks for your replies.  OK, so I go with a pool (single OCS SE Server) at each site as the 2Mb circuit will become saturated I think with OCS traffic, with remote users authenticating for IM/Presence and trying to conduct video conferences - We are only talking about 100 users at both sites!. 


    During the install, how does the remote site (site B) connect up to the pool in the Head office (site A)? so that I have one larger OCS implementation that crosses both sites?.


    If you deploy a singe SE Server at each site, can you start to break out the roles if demand and load starts to become an issue, does the SE pool scale out at all?




    Wednesday, November 26, 2008 8:20 AM
  • Hi,


    If you have cross-site conferences then you will saturate your link in either case as pointed out by deli...However if that would be exceptional then you're safest with a SE server in each site.


    When deploying a SE server you deploy a single server with a local SQL database which is different with an enterprise edition pool where multiple front-end servers share the same SQL Server. So with this mind there is no integration point between the different SE servers other then sharing the active directory as repository for configuration and recipient information and connections between users homed on each of the SE servers. During the deployment of your second SE server you don't have to provide anything special about your first SE server.


    Once you have deployed a SE Server you cannot break out the roles to meet your growing capacity and availability requirements. You will need to deploy a new enterprise edition pool and "move" users from one pool to the other.



    Tonino Bruno





    Wednesday, November 26, 2008 9:10 AM
  • 100 users is not really that much but it depends how many Web A/V Conferences happening the same time and how many users will do cross site at the same time.


    Keep in mind that the codec is elastic that means that it will scale back video and then audio to lower throughput but experience wil vary certainly depending op occupation of WAN link


    One scenario could be to start with one pool and pilot some users in a POC

    Then use the Quality of Experience server to determine the quality of the Audio portion

    Look at the trends when you enable more users

    Add another pool at remote site when WAN is saturated and move users to new pool at remote site


    The other scenario would be starting out with 2 pools as stated earlier

    You can still use the Quality of Experience server to determine the quality




    Wednesday, November 26, 2008 9:31 AM
  • Matt,


    I would recommend deploying an Enterprise Edition server right off the bat, but you can start with a single consolidated Front-End server (no HLB is needed yet).  Then you can later expand that topology to support whatever deployment of conferecing pieces you need to handle your bandwidth concerns.


    Wednesday, November 26, 2008 2:14 PM

    Guys, thanks for your input.  Rumour has it that we might look to get a 100Mb connection out of our building where we would set up a VPN between the 2 sites.  If this is the case, I may look for a single site OCS Enterprise pool.  If that doesn't happen, I will go for the basic SE server at each site....hopefully we wont need external user access.




    Thursday, November 27, 2008 8:26 AM