STP Global

You can set global STP parameters on the STP Global page.

Context

On certain networks, you need to modify STP parameters of some switches to optimize their performance.

Procedure

Choose Service Management > STP > STP Global in the navigation tree to open the STP Global page.

Table 1 describes the parameters on the STP Global page.

**Table 1** STP Global
Parameter		Description
STP		Indicates whether to enable STP. The options are Enable and Disable. By default, STP is disabled.
Instance	Instance	Indicates the ID of a multi-spanning tree instance (MSTI). You can select any MSTI ID ranging from 0 to 48. NOTE: The S2700EI or S2700EI-52P switches MSTI ID ranging from 0 to 16.
	Root Type	Indicates the root type of the switch. The options are: Not set The root type is not set. Primary The switch is configured as root switch of the MSTI. Secondary The switch is configured as the backup root switch of the MSTI. By default, the Not set option is selected.
	Priority	Specifies the priority of the switch. The priority is a major basis for the spanning tree calculation. You can set different priorities for a switch in different MSTIs. NOTE: In an instance, if Root Type is Not set, you can select a priority from the drop-down list box. If Root Type is Primary or Secondary, the priority cannot be set.
Advanced Configuration	BPDU Protection	Indicates whether to enable BPDU protection. The options are Enable and Disable. By default, BPDU protection is disabled. After BPDU protection is enabled , the switch shuts down the edge interfaces that receive BPDUs and notifies the NMS. .The shutdown interfaces can only be manually started by the network administrator.
	TC Protection	Indicates whether to enable topology change (TC) protection. The options are Enable and Disable. By default, TC protection is disabled. The TC protection function prevents topology changes caused by incorrect configuration or malicious attacks.
	Timeout	Indicates the timeout interval. The timeout interval is calculated based on the hello interval and hello time multiplier.
	Working Mode	Indicates the working mode of STP. The options are: MSTP The switch sends MSTP BPDUs in this mode. STP The switch sends STP BPDUs in this mode. RSTP The switch sends RSTP BPDUs in this mode. The default mode is MSTP.
	Max Hops	Indicates the maximum hop count of the spanning tree in an MST region. The default value is 20. This parameter limits the network scale of the spanning tree in the MST region. A configuration message has the maximum hop count on the root bridge. The hop count decreases by 1 every time the configuration message passes a switch. When the hop count decreases to 0, the configuration message is discarded; therefore, switches with larger hop count from the root bridge cannot participate in the spanning tree calculation. This limits the network scale in an MST region.
	Pathcost Standard	Indicates the algorithm used to calculate the path cost. The options are: dot1t Indicates the algorithm defined in IEEE 802.1t. dot1d-1998 Indicates the algorithm defined in IEEE 802.1d. legacy Indicates Huawei proprietary algorithm. The default algorithm is dot1t.
	Bridge-diameter	Indicates the network diameter in the MST region. The default value is 7. The network diameter refers to the maximum number of devices between any two devices on a network. The network diameter reflects the network scale.
	STP Converge Mode	Indicates the STP convergence mode. The options are: Fast In this mode, the switch deletes the useless MAC address entries and ARP entries directly. Normal In this mode, the switch sets the remaining aging time of the MAC address entries and the ARP entries to 0 and ages them. If the number of ARP aging detection times is greater than 0, the switch carries out aging detection of the ARP entries. The default mode is Normal.
Set Bridge Diameter and Timer	forward-delay	Indicates the delay of port status transition. The default value is 1500.
	hello time	Indicates the interval for sending hello packets. The root bridge sends hello packets at this interval to check whether faulty links exist. The default value is 200.
	Max-age	Indicates the maximum lifetime of a configuration message. This parameter determines whether a configuration message has expired. The default value is 2000.

Set the parameters.
Click Apply to complete the configuration.