About autodiscovery
By default, enhanced autodiscovery is enabled. It automatically finds the furthest peer appliance in the network and establishes a trust relationship with it. For example, if you have four appliances (A, B, C, D), appliance A will automatically find D (the furthest from A) and peer with it. This simplifies configuration and scales deployments.
When enhanced autodiscovery is disabled, regular autodiscovery is used. With regular autodiscovery, the appliance peers with its nearest peer appliance. Using the example above, appliance A in this case peers with appliance B.
We recommend enhanced autodiscovery for the following kinds of deployments:
• Serial Cascade Deployments—Ideal for multisite deployments where traffic passes through multiple SteelHeads to reach its destination. Enhanced autodiscovery selects the two outermost SteelHeads for optimization.
• Serial Cluster Deployments—Deploy multiple SteelHeads back-to-back in an in-path configuration to create a serial cluster. This optimizes traffic and allows the next SteelHead to intercept new connections if the previous one reaches its connection limit.
For environments using MAPI or FTP, consider using primary and backup redundancy instead of serial clusters. For large environments, SteelHead Interceptors offer scalability and high availability by creating multi-appliance clusters. For details, see the SteelHead Interceptor Deployment Guide and the SteelHead Interceptor User Guide.
A serial cluster’s bandwidth matches the appliance model in use; it does not increase with multiple appliances in the cluster. For example, a serial cluster that is made up of two 570-M model appliances with a bandwidth specification of 20 Mbps has a cluster bandwidth of 20 Mbps.
If the active appliance in the cluster experiences high CPU load and enters a degraded state, it will still continue to accept new connections.