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AD Sites and Services - DC Locator Process RRS feed

  • Question

  • Hi to all. I am trying to get a handle on the DC Locator Process.

    In my environment there are multiple sites. In AD Sites and Services 'Site Links' are configured as follows:

    1) US

    2) Asia

    3) Europe

    4) Global

    Site Link Bridge contains 1-3 on list above.

    Site Cost 1-3 are set to 102. Link 4 is set to 100.

    domain = me.domain.com

    Within the domain there are multiple sites, each with a configured subnet. Typically many of the sites contain a single domain controller.

    So domain wide there will be 'xx' DC's, site specific a single DC.

    My understanding is the site link with the lowest cost will be used. So in our configuration #4 Global as it has a cost of 100.

    Global contains 4 sites: One from US, One from Asia, Three from Europe

    Question:

    When the DC in the local site is unavailable how is the client request handled?

    My thoughts are ANY DC within the sites listed in site link Global (US, Asia or from one of the three european sites) will service the request. So potentially a DC in Japan might be used to service requests from a client in the UK if DC in local site becomes unavailable.

    is my understanding correct?

    Kind Regards,

    Phil.

    Monday, May 23, 2016 8:50 AM

Answers

  • Hi Phil,

    >>Question:

    When the DC in the local site is unavailable how is the client request handled?

    My thoughts are ANY DC within the sites listed in site link Global (US, Asia or from one of the three european sites) will service the request. So potentially a DC in Japan might be used to service requests from a client in the UK if DC in local site becomes unavailable.

    By default, when a client requests a domain controller, the DC Locator process locates a domain controller in the site of the client. If no domain controller is available in the site, DC Locator returns any domain controller in the domain. If the domain controller is located in another branch site instead of the hub site, communication with the domain controller might be significantly slow. The Try Next Closest Site Group Policy setting in the Default Domain Policy can improve the location of domain controllers by clients that are running Windows Server 2008 or Windows Vista.

    The Try Next Closest Site Group Policy setting uses site link cost values to determine the next closest site to the site of the client. Try Next Closest Site can affect how you configure site link costs because it affects the order in which domain controllers are located. For enterprises that have many hub sites and branch offices, you can significantly reduce Active Directory traffic on the network by ensuring that clients fail over to the next closest hub site when they cannot find a domain controller in the closest hub site. For more information, see Enabling Clients to Locate the Next Closest Domain Controller.

    REF:https://technet.microsoft.com/en-us/library/cc794885(v=ws.10).aspx

    ________________________________________
    Best Regards,
    Cartman
    Please remember to mark the replies as answers if they help and unmark them if they provide no help. If you have feedback for TechNet Support, contact tnmff@microsoft.com.

    Tuesday, May 24, 2016 3:13 AM

All replies

  • Hi Phil,

    >>Question:

    When the DC in the local site is unavailable how is the client request handled?

    My thoughts are ANY DC within the sites listed in site link Global (US, Asia or from one of the three european sites) will service the request. So potentially a DC in Japan might be used to service requests from a client in the UK if DC in local site becomes unavailable.

    By default, when a client requests a domain controller, the DC Locator process locates a domain controller in the site of the client. If no domain controller is available in the site, DC Locator returns any domain controller in the domain. If the domain controller is located in another branch site instead of the hub site, communication with the domain controller might be significantly slow. The Try Next Closest Site Group Policy setting in the Default Domain Policy can improve the location of domain controllers by clients that are running Windows Server 2008 or Windows Vista.

    The Try Next Closest Site Group Policy setting uses site link cost values to determine the next closest site to the site of the client. Try Next Closest Site can affect how you configure site link costs because it affects the order in which domain controllers are located. For enterprises that have many hub sites and branch offices, you can significantly reduce Active Directory traffic on the network by ensuring that clients fail over to the next closest hub site when they cannot find a domain controller in the closest hub site. For more information, see Enabling Clients to Locate the Next Closest Domain Controller.

    REF:https://technet.microsoft.com/en-us/library/cc794885(v=ws.10).aspx

    ________________________________________
    Best Regards,
    Cartman
    Please remember to mark the replies as answers if they help and unmark them if they provide no help. If you have feedback for TechNet Support, contact tnmff@microsoft.com.

    Tuesday, May 24, 2016 3:13 AM
  • Thanks for taking time to read my post and reply.

    Kind Regards,

    Phil.

    Monday, May 30, 2016 9:22 AM