This optional attribute specifies the value of the id attribute for another Arbortext PE サブプロセス pool that can take overflow of processing requests. The cascade attribute allows one pool to take the overflow from another to improve servicing requests. If the Arbortext PE サブプロセス pool being queried determines that it can accept an HTTP request, but no Arbortext PE サブプロセス are available and no additional Arbortext PE サブプロセス can be started, the pool will pass the request to the pool identified by its cascade attribute. You can configure a series of pools to cascade from one to another, where pool A can cascade to pool B, pool B can cascade to pool C, and so on.