Description of Default ResponseDelay Value for RIS

The ResponseDelay value for Remote Installation Service (RIS) defaults to 0 seconds when the service is installed. This setting is meant to improve the performance of RIS when Dynamic Host Control Protocol (DHCP) and RIS are installed on the same server.

The ResponseDelay value controls how quickly the RIS Boot Information Negotiation Layer (BINL) service responds to DHCP packets from Pre-Boot Execution Environment (PXE) clients. For example, if this value is set to five seconds and you boot a PXE client, the client would receive an IP address immediately, but the BINL service would wait five seconds after the client boots to respond to its request for a RIS server.

Although the default ResponseDelay value of 0 may be appropriate in most situations, you may need to set the value higher in some situations. For example, you may need to increase the value in any of the following situations:

• There are multiple forests on the same local LAN (CompanyA.com and CompanyB.com), and at least one RIS server is set to use the Answer Only Known Clients setting.
  
  In this situation, the RIS server for CompanyA may be set to use the Answer Only Known Clients setting, but the CompanyB RIS server is set to use the Answer All setting. A pre-staged client in the CompanyA.com forest may get answered by the RIS server in the CompanyB.com forest because its ResponseDelay value is set to 0 seconds. In this case, it may be necessary to adjust the server's ResponseDelay value to 7 seconds or more to allow the RIS server in the forest/domain in which the client is pre-staged time to respond.
• Non-Microsoft BINL servers are present.
  
  In this case, you may need to adjust the ResponseDelay value depending on the capability of the non-Microsoft BINL server. When a PXE client boots, the only items it may have are a media access control (MAC) address, Globally Unique Identifier (GUID), and IP address. The PXE client is not aware of the differences between the two servers, so it uses whichever server responds first. In this situation it may be preferable to set the ResponseDelay value higher depending on your configuration.
  
  If you are pre-staging your clients, you can check with the vendor of the third-party BINL service to determine if there is a similar value to configure how quickly the server responds to clients. If the non-Microsoft BINL server can also be set to the Answer Only Known Clients setting or some other setting with similar functionality, that may be the most appropriate solution.

Modifying the ResponseDelay Value

WARNING: If you use Registry Editor incorrectly, you may cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that you can solve problems that result from using Registry Editor incorrectly. Use Registry Editor at your own risk.

To modify the ResponseDelay setting, change the data value of the ResponseDelay value in the following registry key: Change this value to 0x7 or higher, depending on your needs and configuration. Also, you should maintain separate DHCP and RIS servers if this value is not 0 and there is a router between the RIS server and one or more clients. Note that clients that have been pre-staged to Active Directory to be serviced by a RIS server do not wait for the ResponseDelay time. In cases in which the client is known (pre-staged), BINL adds its information to the initial DHCP discover request from the client regardless of the ResponseDelay value.