Check Point UTM-1 Edge User Manual page 240

Overview
Multiple Bridges and Spanning Tree Protocol
When using multiple bridges, you can enable fault tolerance and optimal packet routing, by
configuring Spanning Tree Protocol (STP - IEEE 802.1d). When STP is enabled, each
bridge communicates with its neighboring bridges or switches to discover how they are
interconnected. This information is then used to eliminate loops, while providing optimal
routing of packets. STP also uses this information to provide fault tolerance, by re-
computing the topology in the event that a bridge or a network link fails.
Figure 24: Dual Redundant Bridges with STP
226 Check Point UTM-1 Edge User Guide