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Server Roles and HA / DR RRS feed

  • Question

  • I’m new to OCS from Exchange and I’, trying to figure out what the server roles are and how they relate to HA / DR. I am not finding much of anything that actually covers this. I can find lots of talks of Pools, and Load balancers, and how to deploy a few bits in that configuration. But nothing that really says what all of the pieces, where they store data, how to back them up, and how to deploy them in an HA setup. Other then SQL that is. That is very well covered.

     

    This is what I see for Server roles right now. Please correct me.

    ·         IM Conferencing Server. Provides server-managed group Instant Messaging (IM).

    ·         Web Conferencing Server. Enables multiparty data collaboration.

    ·         A/V Conferencing Server. Enables audio and video conferencing.

    ·         Telephony Conferencing Server. Enables audio conference integration with ACP (audio conferencing providers). ACP integration is required to enable large-scale conferencing or audio conferencing with outside users.

    ·         Enterprise Frontend Server    Seems to be separate server role by some examples, or it is a server in a pool with the following roles

    o    Access / IM Conferencing Server. Provides server-managed group Instant Messaging (IM).

    o    Web Conferencing Server. Enables multiparty data collaboration.

    o    A/V Conferencing Server. Enables audio and video conferencing

    ·         Edge server   This is a server in the DMZ with one or more of the follow roles on it.

    o    Access / IM Conferencing Server. Provides server-managed group Instant Messaging (IM).

    o    Web Conferencing Server. Enables multiparty data collaboration.

    o    A/V Conferencing Server. Enables audio and video conferencing.

    ·         Archiving   Compliance server that provides a channel to place all messages that travel through an OCS organization in a journaling database. The journaling database can be maintained based on data retention policies in place for the organization.

    ·         Director   IS shown in a picture but not defined in the documentation that I have ( the deployment and planning guides)

    ·         Address book   Its primary function is providing global address list information from Active Directory to Microsoft Office Communicator 2007. If Communicator accesses Active Directory directly, it could affect network performance. To make address book updates faster and more efficient, the Address Book Server acts as an intermediary to provide the updated local copy of the address list to the Communicator client. Address Book Server updates information for all users—not all users enabled for Office Communications Server. Its secondary and optional function is performing phone number normalization for Communicator telephony integration.

    ·         Backend Database server   SQL server.

    Tuesday, May 22, 2007 6:45 PM

Answers

  • Milton,

     

    We need to set a basis of termonology here first. You're using the term "role" too liberally. There are two places that we can deploy OCS 2007 in a consolidated or expanded configuration: At the pool level and at the edge. Both configurations have all the same features and functionality. An expanded configuration simply allows for more scalability and redundency.

    So, let's first look at a consolidated Enterprise Edition configuration (Standard Edition cannot be expanded). In this configuration we can deploy the following:

    Front End Server

    SQL Backend

    Director

    Edge Server

    Communicator Web Access Server (CWA)

    Mediation Server

    Archiving Server

     

    Now, if we were to take this deployment and make it an expanded configuration at both the pool level and the edge we would have the following:

    Front End Server (responsible for IM/presence/login)

    Web Conferencing Server (web and IM conferences)

    A/V Server (multi-party audio/video MCU)

    Web Components Server (distribution group expansion, storage location for files and handouts in web conferences)

    SQL Backend (storage location of users' presence)

    Director (not required but recommended, allows front end to offload login. It is essentially a FE without any users homed to it)

    Access Edge Server (remotes user access, federation, PIC, external user authentication)

    Web Conferencing Edge Server

    A/V Edge Server

    CWA Server

    Mediation Server (converts SIP TLS traffic to TCP traffic in orderto by to a media gateway which passes to telephone systems)

    Archiving Server (storage or IM conversations and Call Detail Report)

     

    As you can see, in a consolidated mode the front end server is maintaining the roles of front end, web conferencing, A/V and web components. You are able to break these roles out in expanded configuration to allow for more scalability and redundency. Likewise, the Edge Server can have Web Conferencing and A/V Edge server broken out for the same reasons.

     

    Additionally, you add multiple versions of these servers. In a highly scalable and redundant topology you can use a hardware load balancer in front of multiple front end servers and multiple web component servers within a single pool. You can add additional Web Conferencing and A/V Servers to an expanded pool as well, however they do not utilize a hardware load balancer. Each additional Web Confernecing and A/V server gives you additonal scale.

     

    The same holds true for the Edge Server. You can have multiple Access Edge, Web Conferencing Edge and A/V Edge Servers for increased scale and redundency. All Edge server reside with a DMZ. If you were to add additional edge servers in an expanded model they would need to have a load balancer in front and behind them because remote/external users would hit the VIP of the load balancer coming in and any traffic going from the internal network back out would hit a the VIP of the load balancer going back out.

     

    The data for the configuration of the OCS environment lives to two places. It is either stored in Active Directory (OCS configuration data) or in the SQL database (user presence, contact lists, etc.). Therefore, if your AD environment is HA/DR then you can focus on the SQL database. OCS 2007 supports an Active-Passive SQL cluster. With that and standard SQL backup process you will make it HA/DR.

     

    It should be noted that pools are not designed to be split across datacenters. The Public Beta Planning Guide has excellent documentation. Specifically I would look at the diagram on page 34. This diagrams shows a pool in an expanded configuration. This configuration can scale up to 100K+ users and has a lot of room for growth. Also look at the diagram on page 46. This will show you what a global deployment would look like with two datacenters.

    Friday, June 1, 2007 1:00 PM

All replies

  • Have you looked at any of the Public Beta Docs?  This is where you will find the meat of what your looking for also it covers HA as well.

     

    Byron

    Tuesday, May 22, 2007 7:17 PM
  • There is where I Was able to gather what I posted here.

     

    I found a few more roles in additon to the ones that I have listed above.

     

    ·         Mediation Servers

    ·         Forwarding Proxy servers

    ·         CDR

    ·         Web components

     

    This is a good table the covers sever roles

     

    Servers

    Standard Edition Server Environment

    Enterprise Pool, Consolidated Configuration

    Enterprise Pool, Expanded Configuration

    Standard Edition servers

     

     

    Front-end servers

     

    Directors (optional)

     

    Web Components Servers

     

     

    Web Conferencing Servers

     

     

    A/V Conferencing Servers

     

     

    Archiving and CDR Servers

    Mediation Servers

    Forwarding proxy servers

     

    I am trying to desgin a HA site. The documentation for that focuses on Pools for that. Pools of 3 server roles (A/V, webconf, Access), it also mentions frontend pools, and back end pools, and front end servers, and other server roles that seem to be able to exist in a pool but not an edge pool, but that are not really covered. There are roles that are mentioned in one document but not in others, and then in others are called something differently. 

    What I really want is a list of all of the roles. Then a list that shows how those roles can be configured for in an HA configuration.  to have a truly HA install from what I have read so far, I feel that I need:

    • 2 x f5 boxs (one for edge, one for internal) 
    • 6 servers in the Edge, 3 x 2 of the 3 edge roles
    • Maybe 14 or 16 servers in the internal pool,
    • 2 SQL back end servers

    I very much hope that I am way out in left feild here, but I count about 11 server roles that I might or might need to implment OCS properly.

    Tuesday, May 22, 2007 7:30 PM
  • Found another server role. The Focus server role, but is it the focus role or the confrence state server? or is it just somehting is loaded on all servers and not really a role at all? I've seen pictures that say it both ways. 

    ·         The Focus is the conference state server. It is implemented as a SIP user agent that is addressable using a conference URI. The Focus runs in the User Services module of all Front End Servers. All group IM, multiparty A/V, and data collaboration sessions are managed on the server by the Focus.

    I think that the more I read the more I am confused as to what the server roles and how to configure HA, other then I need an f5 and pools of servers.

     

     

    Tuesday, May 22, 2007 7:57 PM
  • Milton,

     

    We need to set a basis of termonology here first. You're using the term "role" too liberally. There are two places that we can deploy OCS 2007 in a consolidated or expanded configuration: At the pool level and at the edge. Both configurations have all the same features and functionality. An expanded configuration simply allows for more scalability and redundency.

    So, let's first look at a consolidated Enterprise Edition configuration (Standard Edition cannot be expanded). In this configuration we can deploy the following:

    Front End Server

    SQL Backend

    Director

    Edge Server

    Communicator Web Access Server (CWA)

    Mediation Server

    Archiving Server

     

    Now, if we were to take this deployment and make it an expanded configuration at both the pool level and the edge we would have the following:

    Front End Server (responsible for IM/presence/login)

    Web Conferencing Server (web and IM conferences)

    A/V Server (multi-party audio/video MCU)

    Web Components Server (distribution group expansion, storage location for files and handouts in web conferences)

    SQL Backend (storage location of users' presence)

    Director (not required but recommended, allows front end to offload login. It is essentially a FE without any users homed to it)

    Access Edge Server (remotes user access, federation, PIC, external user authentication)

    Web Conferencing Edge Server

    A/V Edge Server

    CWA Server

    Mediation Server (converts SIP TLS traffic to TCP traffic in orderto by to a media gateway which passes to telephone systems)

    Archiving Server (storage or IM conversations and Call Detail Report)

     

    As you can see, in a consolidated mode the front end server is maintaining the roles of front end, web conferencing, A/V and web components. You are able to break these roles out in expanded configuration to allow for more scalability and redundency. Likewise, the Edge Server can have Web Conferencing and A/V Edge server broken out for the same reasons.

     

    Additionally, you add multiple versions of these servers. In a highly scalable and redundant topology you can use a hardware load balancer in front of multiple front end servers and multiple web component servers within a single pool. You can add additional Web Conferencing and A/V Servers to an expanded pool as well, however they do not utilize a hardware load balancer. Each additional Web Confernecing and A/V server gives you additonal scale.

     

    The same holds true for the Edge Server. You can have multiple Access Edge, Web Conferencing Edge and A/V Edge Servers for increased scale and redundency. All Edge server reside with a DMZ. If you were to add additional edge servers in an expanded model they would need to have a load balancer in front and behind them because remote/external users would hit the VIP of the load balancer coming in and any traffic going from the internal network back out would hit a the VIP of the load balancer going back out.

     

    The data for the configuration of the OCS environment lives to two places. It is either stored in Active Directory (OCS configuration data) or in the SQL database (user presence, contact lists, etc.). Therefore, if your AD environment is HA/DR then you can focus on the SQL database. OCS 2007 supports an Active-Passive SQL cluster. With that and standard SQL backup process you will make it HA/DR.

     

    It should be noted that pools are not designed to be split across datacenters. The Public Beta Planning Guide has excellent documentation. Specifically I would look at the diagram on page 34. This diagrams shows a pool in an expanded configuration. This configuration can scale up to 100K+ users and has a lot of room for growth. Also look at the diagram on page 46. This will show you what a global deployment would look like with two datacenters.

    Friday, June 1, 2007 1:00 PM