Ken, If you're in a large campus environment that uses fibre runs within the campus, you might (and should - to localize the authentications and logon traffic) create subnets to associate and identify the network infrastructure to AD. If this is the case, we're looking at a well-connected environment that would not use costing per-se within the campus environment. Intrasite connections are not subject to site links as the intersite links are.
Be aware that well-connected is a moving target - usually considered to be (via rule of thimb) 5MB connection. But, it sould be as small as 64k available bandwidth - if it provides the necessary bandwidth to keep up with the out and back replication traffic. Now, if we are connecting a campus environment with, say, T-1 then yes, sites and site links would be correct due to the lower connection rate and a requirement to segment the network into sites. Because we now _have_ sites, site links are needed and the costing can be set to 10, for example, and to coincide with your query. It's reasonable to treat the entire AD Site and Site link environment as a routed infrastructure - because for all intents and purposes it is just that. It is simulating the network infrastructure in AD for the purposes of allowing AD to be sensitive and aware of the network difficulties and limitations. In your example, we have a campus costed at 10. Cost the 128k frame links out to the remote offices at 100. This will reasonably require that anything in the campus be communicated over the appropriate links, and anything going out will take the proper path - over a campus link to the remote site(s). In many cases, these environments will resemble a hub and spoke. Ultimately, there is an upper limit that must be taken into case in the automatic creation and maintenance by the Knowledge Consistency Checker (KCC). The formula to determine if you're getting close to the point where the KCC may be taxed would be (1+D)S^2 <= 100,000, where D = domains, and S = sites. If this number is exceeded, the KCC will push the processor on the DC on which the ISTG is located. Now that the background (and a bit more) is in place, I would set the local campus to 1 or 10, or something else aritrary but consistently smaller. The links from the campus to the remotes would be consistent, but higher by 5 or a magnitude - again, consistency is the issue as long as all links are the same. If you have links from a remote office to remote office, determine if you want communication from office to office. Set the link across there arbitrarily high. Long winded, yes. I hope that this goes a long way in helpingg you to understand the complexity of these issues. They can either be as easy or as complex as you want it to be. Much of it has to do with how your lower 4 layers of the OSI are currently in place. This, you have to play nice with or all of this is for naught. Rick Kingslan - Microsoft Certified Trainer MCSE+I on Windows NT 4.0 MCSE on Windows 2000 MVP [Windows NT/2000 Server] "Any sufficiently advanced technology is indistinguishable from magic." --- Arthur C. Clarke -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]] On Behalf Of Rinehart, Ken Sent: Wednesday, February 06, 2002 11:31 AM To: '[EMAIL PROTECTED]' Subject: RE: [ActiveDir] ISTG and Link costs Rick This is interesting. I trying to gain more info on the significance of costs for non-backup type links. Say for instance a large local campus site with multiple say, 128k frame links out to field offices. I'm guessing you'd set the costs for the local site for 10 for no other reason than to have room for expansion. Would you set the costs differently for the field offices or does the fact that I've already setup a site connector that defines the link enough? Ken -----Original Message----- From: Rick Kingslan [mailto:[EMAIL PROTECTED]] Sent: Tuesday, February 05, 2002 9:07 PM To: [EMAIL PROTECTED] Subject: RE: [ActiveDir] ISTG and Link costs Joe, It's not really _IF_ ISTG is running - it is. It is a role that the KCC assigns and requires, and unlike the Bridgehead, you cannot control who the ISTG role holder is. As to costing - the cost is assigned to the link. The site link is created by you and creates the physical connection to AD that is already assumed by the KCC. It defines the protocol (RPC or SMTP) and the costing based on relative speed of other site links in your infrastructure. The KCC manages the connection objects - the replication topology will take into account the costing you have placed on your links - whenever possible. The lower cost will be favored over a higher cost when creating the connection objects. Site links - created and costed by you. Connection objects - created by KCC, and infulenced by site link costing. ISTG (Intersite Topology Generator) - with the KCC, creates and maintains the replication topology. HTH! Rick Kingslan - Microsoft Certified Trainer MCSE+I on Windows NT 4.0 MCSE on Windows 2000 MVP [Windows NT/2000 Server] "Any sufficiently advanced technology is indistinguishable from magic." --- Arthur C. Clarke -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]] On Behalf Of Joe Sent: Tuesday, February 05, 2002 1:26 PM To: [EMAIL PROTECTED] Subject: [ActiveDir] ISTG and Link costs If ISTG is running do you need to assign link costs between your sites? Does the ISTG handle all of this on its own, or does it consider link costs when it creates its replication model? Thx, Joe List info : http://www.activedir.org/mail_list.htm List FAQ : http://www.activedir.org/list_faq.htm List archive: http://www.mail-archive.com/activedir%40mail.activedir.org/ List info : http://www.activedir.org/mail_list.htm List FAQ : http://www.activedir.org/list_faq.htm List archive: http://www.mail-archive.com/activedir%40mail.activedir.org/ List info : http://www.activedir.org/mail_list.htm List FAQ : http://www.activedir.org/list_faq.htm List archive: http://www.mail-archive.com/activedir%40mail.activedir.org/
