Spanning Tree Protocol (STP) is a network protocol that builds a loop-free logical topology for Local Area Networks. The basic function of STP is to prevent bridge loops and the broadcast radiation that results from them.
Virtual Router Redundancy Protocol (VRRP) provides for automatic assignment of available IP routers to participating hosts. This increases the availability and reliability of routing paths via automatic default gateway selections on an IP subnetwork.
GVRP (Generic Attribute Registration Protocol) allows network devices to dynamically exchange VLAN configuration information with other devices.