Evaluating Network Installation Points

You need to determine suitable local or remote installation points on the network for each RIS server. It might make sense to have your RIS servers each placed locally in a separate LAN. For example, you might want to isolate the installation traffic by using bridges. If that is the case, make sure all components that re 727y2412h direct network traffic, such as a bridges, switches, hubs, and repeaters, can all support the minimum data transmission rate.

Also, it might be feasible to determine the locations of RIS servers based on the DHCP scopes in your organization. If that is the case, you might place your RIS servers on the DHCP servers throughout your enterprise. For more information about combining RIS and DHCP servers, see "Assessing RIS Server Placement" earlier in this chapter.

If you have a small LAN containing a single subnet and no router, a single RIS server can provide service to all PXE-enabled client computers as long as installation traffic does not exceed network bandwidth and server resource limitations. For routed environments, you can configure prestaged clients with settings that direct them to the nearest RIS server in proximity for service. Also consider having high-speed communication links between routers. In a branch office site connected by a slow WAN communication link, you might place a RIS server at the branch site to avoid overloading the WAN link. Because WAN connections are typically slow, avoid having RIS-based operating system installations cross this type of connection. If they do, RIS server traffic can quickly cause a bottleneck and produce unpredictable results.

For this part of your planning process, use job aid "Planning the RIS Network Configuration" (ACIRIS_04.doc) on the Windows Server 2003 Deployment Kit companion CD (or see "Planning the RIS Network Configuration" on the Web at https://www.microsoft.com/reskit) to indicate the following:

The number of RIS server installation points you estimate.

Whether you need to install RIS servers on existing software installation points or on existing DHCP servers.

Whether RIS servers will be placed either locally or remotely (cross-domain locations with respect to RIS client locations on the network).

The type of internetworking connection you plan to use for RIS servers.

You can perform RIS-based operating system installations across routers and domains. You can also perform RIS installations across Active Directory forests, providing that you configure cross-forest trusts. If you need RIS-based installations to cross routers in your organization, you must determine if your routers must be upgraded to support the data transmission rate. Also, for PXE-enabled clients to contact RIS servers located across routers, you must configure the RIS server IP address in the router IP helper tables. By configuring the router in this manner, a PXE-enabled client that broadcasts an IP address request is redirected to the specific RIS server listed in the DHCP scope. As a result, the client does not need to broadcast another DHCP discover packet to locate a RIS server.

DHCP allows you to configure options 60, 66, and 67 for directing PXE-enabled clients to a RIS server without having to update routers with the IP address of the RIS server. However, for reliable RIS service, avoid this configuration because it is known to not function properly for PXE 1.0 and RIS boot floppy disk clients. This configuration also has other drawbacks.

For more information about using options to redirect PXE-enabled clients, see article Q259670, "Using Dynamic Host Configuration Protocol Options 60, 66, 67 to Direct PXE Clients to RIS Servers May Fail" in the Microsoft Knowledge Base. To find this article, see the Microsoft Knowledge Base link on the Web Resources page at https://www.microsoft.com/windows/reskits/webresources.

For this part of your planning process, use job aid "Planning the RIS Network Configuration" (ACIRIS_04.doc) on the Windows Server 2003 Deployment Kit companion CD (or see "Planning the RIS Network Configuration" on the Web at https://www.microsoft.com/reskit) to indicate whether you plan to update your router address tables with the IP addresses of RIS servers.

Forwarding Client DHCP Requests through Routers

Because client service requests are based on the DHCP discovery process, configuring your network to support RIS-based operating system installations across routers has the same requirements as configuring your network to support DHCP across routers.

Routers that you configure to forward DHCP broadcasts also automatically forward client service requests, however, you must ensure that the requests are forwarded to the proper RIS servers in addition to any DHCP servers. Depending on the model in use and the specific configuration, your router might support DHCP broadcast forwarding to a subnet, a specific host, or another router interface. If you use Windows Server 2003 DHCP but you place your RIS servers on separate computers, or if you use a third-party DHCP service, you must ensure that the routers forward DHCP broadcasts to both the DHCP and RIS servers. Otherwise, the client does not receive a reply to its remote boot request.

For this part of your planning process, use job aid "Planning the RIS Network Configuration" (ACIRIS_04.doc) on the Windows Server 2003 Deployment Kit companion CD (or see "Planning the RIS Network Configuration" on the Web at https://www.microsoft.com/reskit) to indicate whether you plan to configure your routers to forward DHCP broadcast traffic.