Assessing Bandwidth Usage

Bandwidth usage and its impact on network traffic and server load can be a major concern for corporations that are implementing browser software. Microsoft designed Internet Explorer as a "bandwidth-smart" application with built-in mechanisms for caching and compressing data, as well as tools that optimize information dynamically. System policies to limit bandwidth and restrict access to bandwidth-intensive features, such as audiovisual components, provide additional control of bandwidth usage.

Internet Explorer achieves optimal bandwidth use by focusing on the most efficient methods for minimizing network traffic while maximizing performance. This occurs primarily by:

• Optimizing data through caching, compression, and other methods
• Using system policies and restrictions to control bandwidth

In addition, organizations that distribute Internet Explorer from Web download sites should consider the impact of this distribution media on bandwidth usage and server load. For more information about potential bandwidth issues, review "Assessing Network Performance and Bandwidth Issues" later in this chapter.

Optimizing Data Through Caching, Compression, and Other Methods

Internet Explorer uses the following methods to minimize the amount of data transmitted over the network and maximize the performance for the end user:

• Caching content - Internet Explorer optimizes bandwidth by caching Web content. The first time you connect to a Web page, Internet Explorer downloads the page and its supporting content to a cache stored in the Temporary Internet Files folder on your hard disk. By default, Internet Explorer uses the cached content instead of downloading new content when you return to browse a cached page. Using cached content provides faster performance for browsing Web sites, because the same content is not downloaded over and over again.
• Providing data compression with the HTTP 1.1 protocol - For faster, more efficient downloading of Web content, Internet Explorer supports the HTTP 1.1 protocol. This protocol compresses packets of data transferred with the HTTP protocol, which can boost performance as much as 50 to 100 percent over compressed data using HTTP 1.0. Web communications using HTTP 1.1 require fewer delays and consume less bandwidth, and Web content downloads faster to the browser. By default, HTTP 1.1 communications are enabled in Internet Explorer to optimize performance when the browser interacts with servers that support HTTP 1.1.
• Supporting bandwidth-smart tools to develop Web content - Internet Explorer supports the Portable Network Graphics (PNG) specification, Dynamic HTML, and the Microsoft DirectX multimedia extensions, which enable developers to design faster, more bandwidth-efficient graphics and interactive and animated Web content. Also, Internet Explorer includes the Microsoft Virtual Machine, which provides optimum performance for Java applets. For more information about these tools, see the MSDN Online Web site.

Using System Policies and Restrictions to Control Bandwidth

You can use Internet Explorer system policies and restrictions to control access to bandwidth-intensive features and to enforce a limit on bandwidth usage. For example, you can control the following capabilities:

• Access to multimedia capabilities - By default, Internet Explorer shows or plays a wide range of standard multimedia content, including graphics, video, and audio. Internet Explorer also uses image-dithering technology to smooth images, so they appear less jagged. However, multimedia content and dithering can use a significant amount of network bandwidth, causing Web pages to download and be displayed slowly.

  Using system policies and restrictions, you can limit access to multimedia functions, such as Web pictures, animation, videos, and sound, which allows Web pages with multimedia content to download faster and use less bandwidth. You can also turn off image dithering to speed up image display time. Be aware, however, that when multimedia features are disabled, the pages will not appear as intended and you may miss some relevant content.

• NetMeeting audio and video throughput - NetMeeting intelligently manages the throughput (average bandwidth use) of audio, video, and data over the network on a client-specific basis. This process ensures the smooth operation of the separate NetMeeting components and the bandwidth resources of the network.

  You may want to further manage or restrict NetMeeting audio and video depending on the needs of your users and the capacity of your network systems. Using system policies and restrictions, you can set a specific number limit for the audio and video throughput, which controls bandwidth usage by restricting NetMeeting audio and video streams.

• Access to offline features - If you have many users who download Web content for offline browsing, you may be concerned about the server load. To address this concern, Internet Explorer provides system policies and restrictions that let you disable or limit access to offline functions. For example, you can reduce bandwidth usage by increasing the minimum number of minutes between scheduled updates of offline content and reducing the size of subscriptions that can be updated for offline viewing.

For more information about using Internet Explorer system policies and restrictions, see Appendix E, "Setting System Policies and Restrictions."