1-11 MSTP ConfigurationGo to these sections for information you are interested in:z Overviewz MSTP Configuration Task Listz Configuring Root Bridgez Configuring Leaf Nodesz Performing mCheck Operationz Configuring Guard Functionsz Configuring Digest Snoopingz Configuring Rapid Transitionz Configuring VLAN-VPN Tunnelz MSTP Maintenance Configurationz Enabling Trap Messages Conforming to 802.1d Standardz Displaying and Maintaining MSTPz MSTP Configuration Examplez VLAN-VPN Tunnel Configuration ExampleOverviewAs a Layer 2 management protocol, the Spanning Tree Protocol (STP) eliminates Layer 2 loops byselectively blocking redundant links in a network, and in the mean time, allows for link redundancy.Like many other protocols, STP evolves as the network grows. The later versions of STP are RapidSpanning Tree Protocol (RSTP) and Multiple Spanning Tree Protocol (MSTP). This chapter describesthe characteristics of STP, RSTP, and MSTP and the relationship among them.Spanning Tree Protocol OverviewWhy STPSpanning tree protocol (STP) is a protocol conforming to IEEE 802.1d. It aims to eliminate loops on datalink layer in a local area network (LAN). Devices running this protocol detect loops in the network byexchanging packets with one another and eliminate the loops detected by blocking specific ports untilthe network is pruned into one with a tree topology. As a network with a tree topology is loop-free, STPprevents packets in it from being duplicated and forwarded endlessly and prevents device and networkperformance degradation caused by data loops.In the narrow sense, STP refers to IEEE 802.1d STP; in the broad sense, STP refers to the IEEE 802.1dSTP and various enhanced spanning tree protocols derived from that protocol.Protocol Packets of STPSTP uses bridge protocol data units (BPDUs), also known as configuration messages, as its protocolpackets.
