General parameters

Spanning tree operating When Spanning Tree is turned off, a device does not send any Spanning Tree packets and passes received packets along instead of processing them itself.
Protocol version
- Classic: Uses the classical STP to determine network topology.
- Rapid: Uses the RSTP method to determine network topology.
Note: RSTP is compatible with STP. Network components which only support classical STP continue to be supported where RSTP is operational.
Path cost computation
- Classic: Uses the classical STP method to compute path costs.
- Rapid: Uses the RSTP method to compute path costs.
Bridge priorityDefines the priority of the bridge in the LAN. This can influence which bridge should preferably be made root bridge by the Spanning Tree Protocol.
Note: So as to maintain compatibility with RSTP, this value should only be adjusted in steps of 4096 owing to the fact that RSTP uses the lower 12-bits of this 16-bit value for other purposes.
Maximum AgeThis value defines the time (in seconds) after which a bridge drops messages received through Spanning Tree as ‘aged’. This parameter defines how quickly the Spanning Tree algorithm reacts to changes, for example due to failed bridges.
Hello TimeThis parameter defines (in seconds) in which intervals a device selected to be the root bridge sends Spanning Tree information into the LAN.
Forward delayThis time (in seconds) determines how much time must pass at a minimum before a Spanning Tree port can change the status (listening, learning, forwarding).
Note: When using RSTP the forwarding delay often has no effect because RSTP has suitable mechanisms of its own to prompt a rapid switching into the forwarding state.

Note: Modifying any of these three time values is only recommended for those with exact knowledge of the Spanning Tree protocol. An adjustment can be useful in order to optimize reaction times after topology changes or to achieve stable performance in networks with many 'bridge hops'.
Transmit-hold countNumber of BPDUs which can be transmitted by RSTP before a one second pause commences.
Note: When using classical STP the transmit-hold count has no effect.