Microsoft released ISA Server 2004 Service Pack 2. The new service pack brings new three features, including enhanced caching, HTTP compression, and traffic prioritization.
ISA Server 2004 SP2 can now cache content downloaded with Background Intelligent Transfer Service (BITS), which will help when handling updates and service packs. So for example, if a network doesn't use Windows Server Update Services (WSUS) or Systems Management Server (SMS) then BITS caching can help reduce overall network traffic when users try to download updates directly from Windows Update. The caching feature will save copies of downloaded content and then transfer requested data a little at a time depending on bandwidth availability.
HTTP compression is a common way to reduce overall bandwidth usage. You can think of it as similar to using ZIP to compress a file before sending it to someone. ISA Server 2004 SP2 can now request and serve compressed content.
The new traffic prioritization feature introduces a way to globally handle quality of service (QoS) for applications. Microsoft said that "ISA Server 2004 SP2 supports setting the DiffServ field in IP packets based on URLs. The DiffServ field is used to determine the quality of service for an IP packet, allowing customers to give higher priority to important applications. DiffServ values for URLs can be configured at both the head office and branch offices allowing for traffic prioritization between locations."
The new service pack is available at Microsoft's ISA Server-related Web site.