I only have a single site. Instead of setting each boundary group to assign a site, what's the best way to assign all clients to a single site?
Based on the clients you can use single boundary group .
I have 4000 Client i created below in single boundary /group . Subnet based discovery and created collections .Now i split task for each collection and easy to manage .
Client - 2
2000+ client in 4 different locations
I use primary server and created different boundary group and Installed Distribution point/Group each client location .
I am assuming when you state "assign a site" you are referring to the sites that you see in your Boundaries section located in the Administration workspace under Hierarchy Configuration. If this is the case, then all you have to do is simply create a Site Assignment boundary group under the Boundary Groups section and add all of the sites listed in the Boundaries section. This will tell all of the clients to use that one Site Server. When you create a new Boundary Group, you will click the Add button in the Boundaries: section of the Boundary Group properties box and you will add all of your sites there to assign your one Site Server to those clients.
Now if you have multiple Distribution Points, you want to make sure that you do not overlap any Boundaries, because this can cause some issues especially if you have slow WAN links. You always want to keep your Site Assignment and your Content Location Boundary Groups separate. For instance, if you have a Standalone Primary Site server that also has the DP role installed, I would still create two separate Boundary Groups, one as a Site Assignment Boundary Group and the other as Content Location Boundary Group. You create the Site Assignment Boundary Group to assign clients to the Site Server, then you will create a separate Content Location Boundary Group and assign clients to the Distribution Point that is installed on the Site Server as well. It is best to keep them separate so you don't have overlapping issues occur, because even though you have one Site Server, you may eventually begin setting up remote Distribution Points in remote locations to speed up data transfers to clients in those remote locations. If you just create one Boundary Group and make that Boundary Group both a Site Assignment and a Content Location Boundary Group and then you begin adding remote DPs in your environment and you create separate Content Location Boundary Groups for them, but if you forget that you created that first Boundary Group as a Site Assignment and a Content Location Boundary Group, clients could use both DPs and create an overlap. You don't want remote clients reaching across a slow WAN link to get content from the DP on the Site Server since that will kill the bandwidth and disrupt end user's work. This is the reason for creating separate Boundary Groups, one for Site Assignment (assigns clients to a Site Server) and one for Content Location (assigns clients to a Distribution Point). Most clients will use Active Directory Sites and Services to find which DP has the lowest site link cost (closest to them), but you still do not want to rely on this.