1. In the console tree of ISA Server Management, click General:
For ISA Server 2004 Enterprise Edition, expand Microsoft Internet Security and Acceleration Server 2004, expand Arrays, expand Array_Name, expand Configuration, and then click General.
For ISA Server 2004 Standard Edition, expand Microsoft Internet Security and Acceleration Server 2004, expand Server_Name, expand Configuration, and then click General.
Under Global HTTP Policy Settings, click Specify Diffserv Preferences to open the HTTP Diffserv properties.
On the General tab, you can select whether Quality of Service bits will be set by ISA Server.
On the Priorities tab, you can add and configure priorities and DiffServ values to be supported by ISA Server. You will assign these priorities to URLs and domains on other tabs of the HTTP Quality of Service properties. To add a priority, click Add to open the Add Priority dialog box.
After you add the priorities, you can order them. If a packet is assigned to a specific priority based on a URL or domain, but cannot be assigned that priority based on packet size, it defaults to the next priority on the list.
You can also select Allow special handling, so that headers will be handled with a different (typically, higher) priority than other parts of requests and responses.
In the Add Priority dialog box, provide a priority name, and specify the DiffServ bits, which are also known as the Differentiated Services Code Point (DSCP), as a six-digit binary string. The binary string should match the binary string used by your router for a particular Quality of Service (QoS) setting. In SizeLimits, you can apply a size limit in bytes, so that the priority will only apply to requests or responses of a maximum size. A request or response that exceeds the specified maximum size will receive the next priority in the order. After you configure the priority, click OK to close the dialog box.