RE: [ActiveDir] Site link costs

[Rick Kingslan]

Title: Site link costs

Cathy, My approach to sites, site link objects, and topology overall has been to look at the physical/logical layout of the network as it pertains to the Layer 2/Layer 3 communication. Remember what we’re telling AD with Sites, Subnet objects, site links, etc – This is what the network looks like, or how I want you to THINK the network looks like. So, when you crate a site (a site is a collection of subnet objects that are ‘local’ to each other) you are telling AD that this site and another site will communicate Inter-Site.  While the subnets inside the site will be deemed ‘Intra-site’. To that, I would question the subsidiary that left their objects in the Default-First-Site-Name site.  Are they all local to all other objects in that site?  Does it make sense from a local vs. remote perspective? I managed the AD of a company that used ATM practically to all of our ~50 remote sites.  (Telecomm heavy company – we had lots of carrier agreements with b-width to spare…)  I STILL treated remote sites not in the campus with the Data Center as a remote site.  They might have appeared as well connected, but that could have changed at any time. As to costing for site links – you can do that, but if there is only on site link from A to B, the cost isn’t going to have much impact.  There still is only one way to get there.  Now, if you want redundancy for site links, you CAN add links from C to B, and cost that one higher than A to B.  You will also want to take into account site link bridging and determine if you want that on or off. (Site link bridging transitively connects one site through another site with a virtual link – the site link bridge.)  Typically, I have turned off site link bridging to accomplish what I need to have done – not leaving those decisions up to the mechanisms that might not have a clear idea of what my topology was really like. The key here is much more in the realm of Network considerations than OS.  The KCC is still going to connect things – but not optimally until you set up a site topology that emulates efficiencies that you can only hope are in your network design. Rick   From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of O'Brien, Cathy 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