A method and system are provided for broadcast message filtering in SAS expanders. Common SAS topology defined by ANSI T10 specification only supports spanning tree topology (without loops) interconnection among multiple end devices and expander devices. Broadcast message filtering provides a mechanism to selectively discard broadcast messages, or primitives, in the SAS expanders to break the infinite loop path that broadcast primitives can traverse. This enables new SAS physical topologies with loops that are otherwise difficult or impossible to realize using SAS expanders that handle primitive broadcasts according to the definition of the SAS standard. By allowing redundant paths in a SAS topology, the problem of infinite broadcast flooding in SAS topology is reduced. Selectively forwarding broadcast messages can be based on whether the broadcast was originated at the source phy, or received by the source phy, or based on whether the source phy is a filtered phy.