A. The ZebOS Layer-2 Protocol Modules are a family of Ethernet bridging, Spanning Tree, Multicast and VLAN software packages that provide advanced Layer-2 functionality for vendors building routing and switching equipment. Each Layer-2 Protocol Module leverages the command line interface and the kernel management of the ZebOS Network Services Module (NSM). The Layer-2 family includes Ethernet MAC bridging, Spanning Tree Protocol (STP), Rapid Spanning Tree Protocol (RSTP), Multiple Spanning Tree Protocol (MSTP), VLAN and hardware forwarding APIs, IGMP Snooping, GARP Multicast Registration Protocol (GMRP), GARP VLAN Registration protocol (GVRP), Port and Protocol VLAN classification (802.1v), VLAN Stacking, 802.1x Port Authentication, and Link Aggregation (802.3ad).