Cascaded caching can be used from release 4.6B and from Knowledge Warehouse release 451A. Cascaded caching is also known as multi-layer caching.

Previously, Knowledge Provider’s Content Management Service provided a simple caching concept. With this system, once content was accessed, it was stored in a cache in the same location as the content server. In other words, the Cache Server retrieved the content directly from the Content Server.

The development of the caching concept to include cascaded caching is of most benefit in large, distributed systems. In such scenarios, a cache server can also get content from another cache server.

When multi-layer caching is used, the path from the location of the client to the location of the content server is established. There can be cache servers both at the client location and the content server location. This allows a cache server at the client location to get a requested document from the cache server at the content server location.

Multi-layer caching is intended to optimize access times. This has the added advantage that URLs can be processed by the content server aliases, so that requests coming in via firewall proxies can be forwarded to their destinations as directly as possible.

Cache server and content server aliases are only used if the client location is known when the URL is being contructed. The client location is known if the Knowledge Provider itself requested the URL. If, on the other hand, the URL was requested by another application, and the Knowledge Provider does not know where the URL is going to be used, the system cannot find out the location of the client. In this case, the URL that points directly to the content server is always returned. The cache server and content server alias are not taken into account.