This section describes how you can improve network performance using Novell BorderManager Proxy Services and caching.
Next to security, performance is of major concern. When you connect to the Internet, performance problems can occur for many reasons, including the following:
Connections to the Internet are slower than connections within the intranet.
Internet users can access enormous amounts of information.
The same information is being accessed multiple times, and replicated information is clogging the networks.
Large graphics, video, and audio files are typical for Web sites, take up more space, and take longer to download than plain text.
Novell BorderManager Proxy Services can greatly improve network performance by locally caching frequently requested Internet information. In general, Proxy Services stores copies of frequently requested Web information closer to the user, thereby reducing the number of times the same information is accessed over an Internet connection, the download time, and the load on the remote server.
Novell BorderManager provides advanced caching technologies to address the performance issues. These are discussed in the next section. For more detailed information on Proxy Services, refer to Section 5.0, Proxy Services Overview and Planning.
There are three primary ways to use caching to improve performance:
In Web client acceleration, the proxy server is located between the clients and the Internet or intranet. The proxy server intercepts requests from clients for Web pages and supplies the requested pages, if cached, to the client at LAN speed. This eliminates the delay that occurs when the origin Web site is accessed using a slower link, and it also minimizes the traffic between the corporate network and the Internet or intranet.
The proxy server works with the NDS or eDirectory access control policies to make sure that the client browser has authorization to access the data.
Use Web client acceleration to improve performance for sites that have the following:
Multiple clients
Remote locations that route through a central or main site to access the Internet
A need for access control at the user level
A need for globally and centrally maintained multiple firewall services
With Web server, or HTTP, acceleration, the proxy server acts as a front end to one or more publishing Web servers and caches all information that belongs to the Web server. When a client requests information from a Web server, the request is redirected to the proxy server (the user enters a URL to the accelerator server rather than to the origin host). The proxy server supplies the cached pages to the client at high speed. This method accelerates access and takes the request load off the Web servers, enabling them to respond to more users.
The reverse proxy cache server is an automatic firewall to the publishing servers. The reverse proxy cache server caches all static information (typically up to 90 percent of a Web site), freeing up the publishing server to open connections and deliver the dynamic data. It also protects the IP addresses of the origin servers, thereby increasing security.
Use reverse proxy cache for sites that have the following:
Frequently used Web servers
A need for centralized access control on all intranet Web servers
Intranet publishing servers that store public and private data
A mix of Internet and intranet Web server platforms
With network acceleration, or hierarchical caching, multiple proxy servers are configured in a hierarchical topology. The proxy servers are connected in a parent, child, or peer relationship. When a miss occurs, the proxy contacts the other servers in the hierarchy to find the requested cached information. The nearest proxy cache or the proxy cache with the highest assigned priority that has the requested information forwards it to the requesting proxy server, which in turn forwards it to the requesting client.
Hierarchical caching reduces the WAN traffic load and increases valuable bandwidth. In addition, because the requested information is sent from the nearest proxy server, network delays are minimized. This reduces user wait time and increases user productivity.
Use hierarchical caching for sites that have the following:
Slow Internet links
Multiple LAN segments that can be used to store data closer to users
Congestion or delay at LAN points in the WANs