RE: [ActiveDir] Site link costs

[Bernard, Aric]

Title: Site link costs

Cathy,   I think you have got a handle on the big picture – AD will work without creating any explicit site links, which implies that all site will be members of the DefaultSiteLink, however this may not be the optimal configuration and in turn may result in a “replication topology” that is undesirable or at least lackluster in terms of performance.  To quote Charlie… “it all depends on your [network] topology that you have”.     Regards,   Aric   From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of O'Brien, Cathy Sent: Thursday, July 21, 2005 2:18 PM To: ActiveDir@mail.activedir.org Subject: RE: [ActiveDir] Site link costs   Thanks to all of you who responded.   I think part of my problem is with semantics. As Aric says, it's important to differentiate between sites, site links, and connection objects. People here at work are saying that AD will create its own site links, but actually, AD just uses the DefaultSiteLink to create connection objects if we don't explicitly create site links, right? AD doesn't actually create any new site link objects on its own? I certainly don't see any in our environment that we didn't explicitly create.   I guess what these others mean is just that we don't HAVE to create any site links. While I think our experience is showing that we probably should, they're correct that we don't absolutely have to. I just wanted to be sure though that I was understanding the concepts underneath correctly.   Homework for the weekend: read through the AD Replication Topology Technical Reference :-)    From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Bernard, Aric Sent: Thursday, July 21, 2005 12:01 PM To: ActiveDir@mail.activedir.org Subject: RE: [ActiveDir] Site link costs While I know absolutely nothing about your environment aside from what you mention below, but I would have to make an assumption that if your AD site topology were configured properly you could have accomplished what you want without “deactivat[ing] the ability for AD to create its own links”.  Your approach is certainly not a best practice for most environments.    Further more; it is important to differentiate between sites, site links and connection objects.  In every forest, sites and associated site links must be implemented manually/programmatically [1] as the KCC/ISTG only handles the creation of connection objects between DCs based on the site topology explicitly defined in the AD.  If you were seeing connection object being created automatically between servers that you “disapproved” of then an error existed in the site topology you defined.  Keep in mind that your site topology consists of many things including sites, site links, site link bridges, costs, schedules, preferred bridgehead servers (optionally), and more.   [1] The exception to this is the DefaultFirstSite and DefaultSiteLink.   Regards,   Aric   From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Carerros, Charles Sent: Thursday, July 21, 2005 11:36 AM To: 'ActiveDir@mail.activedir.org' Subject: RE: [ActiveDir] Site link costs   Great question, we just had this at our place.  We just finished deploying a W2K3 AD structure across the globule with each division using their own sub domain.    We are creating our site links manually.  And by saying "We" I mean one of the five Enterprise admins across the globe.  We have deactivated the ability for AD to create its own links so we don't have to worry about oddities.   The reason for this is so we can control how often and WITH WHO each site replicates.  Right now we have the site that hosts the first DC for each domain replicating back to sites with root domain controllers but all other domain sites only replicate with each other and their first DC.  This means that if the link between our root domain controllers and that primary domain controller site was to go away we wouldn't have replication with them.    The links that were being created by AD weren't what we wanted.  We had sites in Italy replicating with New Jersey and sites in Mexico replication with Ireland.  I think this had something to do with our routing tables, firewall placements and frame relay clouds that we are using across the globe.   So, I guess it all depends on your topology that you have.   Charlie   -----Original Message----- From: O'Brien, Cathy [mailto:[EMAIL PROTECTED] Sent: Thursday, July 21, 2005 1:06 PM To: ActiveDir@mail.activedir.org Subject: [ActiveDir] Site link costs Sorry for the basic question... Our company just upgraded our NT4 domains in-place as child W2K3 domains under an empty W2K3 forest root domain. 22 sites and their associated subnets were established, with one subsidiary leaving all their objects in the default first site because they feel their bandwidth will support it. However, we're currently having heated discussions regarding AD and site topology. Some IT members are saying that there is no need to manually create site links or assign properties such as cost and replication interval. They say that if we don't do this, then AD does it automatically and it will do a better job than we would anyway. I  thought that the KCC needed the site topology info to be provided (whether manually or programmatically) so that it could automatically create the connection objects (provided you're not manually creating them). So who is confused here, me or them? This should be basic stuff, and I want to understand it correctly :-). TIA, Cathy