D-Link DGS-3620-28TC-SI Product Manual - Page 99

xStack® DGS-3620 Series Managed Switch Web UI Reference Guide 802.1Q-2005 MSTP 802.1D-2004 RSTP 802.1D-1998 STP Forwarding Learning Disabled Disabled Disabled No No Discarding Discarding Blocking No No Discarding Discarding Listening No No Learning Learning Learning No Yes Forwarding Forwarding Forwarding Yes Yes RSTP is capable of a more rapid transition to a forwarding state - it no longer relies on timer configurations - RSTP compliant bridges are sensitive to feedback from other RSTP compliant bridge links. Ports do not need to wait for the topology to stabilize before transitioning to a forwarding state. In order to allow this rapid transition, the protocol introduces two new variables: the edge port and the point-to-point (P2P) port. Edge Port The edge port is a configurable designation used for a port that is directly connected to a segment where a loop cannot be created. An example would be a port connected directly to a single workstation. Ports that are designated as edge ports transition to a forwarding state immediately without going through the listening and learning states. An edge port loses its status if it receives a BPDU packet, immediately becoming a normal spanning tree port. P2P Port A P2P port is also capable of rapid transition. P2P ports may be used to connect to other bridges. Under RSTP/MSTP, all ports operating in full-duplex mode are considered to be P2P ports, unless manually overridden through configuration. 802.1D-1998/802.1D-2004/802.1Q-2005 Compatibility MSTP or RSTP can interoperate with legacy equipment and is capable of automatically adjusting BPDU packets to 802.1D-1998 format when necessary. However, any segment using 802.1D-1998 STP will not benefit from the rapid transition and rapid topology change detection of MSTP or RSTP. The protocol also provides for a variable used for migration in the event that legacy equipment on a segment is updated to use RSTP or MSTP. The Spanning Tree Protocol (STP) operates on two levels: 1. On the switch level, the settings are globally implemented. 2. On the port level, the settings are implemented on a per-user-defined group of ports basis. STP Bridge Global Settings On this page the user can configure the STP bridge global parameters. To view the following window, click L2 Features > Spanning Tree > STP Bridge Global Settings, as show below: 89