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NVIDIA Onyx User Manual v3.10.4504 LTS

Spanning Tree Protocol

The operation of Rapid Spanning Tree Protocol (RSTP) provides for rapid recovery of connectivity following the failure of a bridge/bridge port or a LAN. The RSTP component avoids this delay by calculating an alternate root port, and immediately switching over to the alternate port if the root port becomes unavailable. Thus, using RSTP, the switch immediately brings the alternate port to forwarding state, without the delays caused by the listening and learning states. The RSTP component conforms to IEEE standard 802.1D 2004.

RSTP enhancements is a set of functions added to increase the volume of RSTP in NVIDIA switches. It adds a set of capabilities related to the behavior of ports in different segments of the network. For example: the required behavior of a port connected to a non-switch entity, such as host, is to converge quickly, while the required behavior of a port connected to a switch entity is to converge based on the RSTP parameters.

Additionally, it adds security issues on a port and switch basis, allowing the operator to determine the state and role of a port or the entire switch should an abnormal event occur. For example: If a port is configured to be root-guard, the operator will not allow it to become a root-port under any circumstances, regardless of any BPDU that will have been received on the port.

Port Priority and Cost

When two ports on a switch are part of a loop, the STP port priority and port path cost configuration determine which port on the switch is put in the forwarding state and which port is put in the blocking state.

To configure port priority use the following command:

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            switch (config interface ethernet <inf>)# spanning-tree port-priority <0-240>

To configure port path cost use the following command:

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            switch (config interface ethernet <inf>)# spanning-tree cost <1-200000000>

Port Type

Port type has the following configuration options:

edge – is not assumed to be converged by the RSTP learning/forwarding mechanism. It converges to forwarding quickly.

Note

It is recommended to configure the port type for all ports connected to hosts as edge ports.
normal – is assumed to be connected to a switch, thus it tries to be converged by the RSTP learning/forwarding. However, if it does not receive any BPDUs, it is operationally moved to be edge.
network – is assumed to be connected only to a switch or bridge.

Each of these configuration options is mutually exclusive.

Port type is configured using the command spanning-tree port type. It may be applied globally on the switch (Config) level, which configures all switch interfaces. Another option is to configure ports individually by entering the interface’s configuration mode.

Global configuration:

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            switch (config)# spanning-tree port type {edge , normal , network} default

Interface configuration:

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            switch (config interface ethernet <inf>)# spanning-tree port type {edge , normal, network}

For more information about this feature and its potential applications, please refer to the following community post:

How To Configure Switch Port Types with NVIDIA Onyx

BPDU Filter

Using BPDU filter prevents the CPU from sending/receiving BPDUs on specific ports.

BPDU filtering is configured per interface. When configured, the port does not send any BPDUs and drops all BPDUs that it receives. To configure BPDU filter, use the following command:

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            switch (config interface ethernet <inf>)# spanning-tree bpdufilter {enable | disable}

BPDU Guard

BPDU guard is a security feature which, when enabled, will move the port to "down (suspended)" mode in case it receives BPDU packets. This feature becomes useful when connecting to an unauthorized switch.

To configure BPDU guard use the following command:

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            switch (config interface ethernet <inf>)# spanning-tree bpduguard {enable , disable}

Logging Example In Case of a BPDU Guard Event

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            Oct 29 22:55:30 r-anaconda-01 issd[7375]: TID
140652362820224: [issd.WARNING]: NPAPI_WRN: warning RstHandleInBpdu Received
BPDU on Port Eth1/12 with BPDU guard enabled. Disabling Port.

Loop Guard

Loop guard is a feature that prevents loops in the network.

When a blocking port in a redundant topology transitions to the forwarding state (accidentally), an STP loop occurs. This happens when BPDUs are no longer received by one of the ports in a physically redundant topology.

Loop guard is useful in switched networks where devices are connected point-to-point. A designated bridge cannot disappear unless it sends an inferior BPDU or brings the link down on a point-to-point connection.

Note

The loop guard configuration is only allowed on “network” and “normal” port types.

If loop guard is enabled and the port does not receive BPDUs, the port is put into an inconsistent state (blocking) until the port starts to receive BPDUs again. A port in the inconsistent state does not transmit BPDUs. If BPDUs are received again, loop guard alters its inconsistent state condition. STP converges to a stable topology without the failed link or bridge after loop guard isolates the failure.

Disabling loop guard moves all loop-inconsistent ports to listening state.

To configure loop guard use the following command:

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            switch (config interface ethernet <inf>)# spanning-tree guard loop

Root Guard

Configuring root guard on a port prevents that port from becoming a root port. A port put in root-inconsistent (blocked) state if an STP convergence is triggered by a BPDU that makes that port a root port. The port is unblocked after the port stops sending BPDUs.

To configure loop guard use the following command:

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            switch (config interface ethernet <inf>)# spanning-tree guard root

MSTP

Spanning Tree Protocol (STP) is a mandatory protocol to run on L2 Ethernet networks to eliminate network loops and the resulting broadcast storm caused by these loops. Multiple STP (MSTP) enables the virtualization of the L2 domain into several VLANs, each governed by a separate instance of a spanning tree which results in a network with higher utilization of physical links while still keeping the loop free topology on a logical level.

Up to 64 MSTP instances can be configured on a switch.

RPVST

Rapid Per-VLAN Spanning Tree (RPVST) flavor of the STP provides finer-grained traffic by paving a spanning-tree instance per each configured VLAN. Like MSTP, it allows a better utilization of the network links comparing to RSTP.

The following figure exhibits a typical RPVST network configuration to get a better utilization on the inter-switch trunk ports.

RPVST_Network_Config-version-1-modificationdate-1722495449623-api-v2.png

RPVST and VLAN Limitations

When the STP of the switch is set to RPVST, spanning tree is set on each of the configured VLANs in the system by default. To enable the spanning tree mode, the command “spanning-tree” must be run.

Each VLAN runs an STP state machine and an RPVST instance. There is a global limitation on the number of active state machines that can operate inNVIDIA Onyx. Enforcement of this limitation is done through the maximum number of VLANs allowed in the system (128).

The state machine takes attributes like forward time, hello time, max age and priority, etc.

Note

When configuring priority on a VLAN in RPVST, the operational priority given to the VLAN is a summation of what the user configured and the value of the VLAN itself. For example, running “spanning-tree vlan 10 priority 32768” yields a priority of 32778 for VLAN 10.

RPVST and RSTP Interoperability

RPVST_and_RSTP_Cluster-version-1-modificationdate-1722495451957-api-v2.png

RPVST domains can be interconnected by a standard 802.1Q domain that runs RSTP protocol. While the RSTP domain builds a single common instance spanning tree, the RPVST domains at the edge continue to build a tree per VLAN while exchanging tagged RPVST multicast BPDUs.

(This exchange may happen on untagged RPVST BPDUs as well.) The switch devices that are in the boundary between the RPVST and the RSTP domains should be configured as RPVST mode.

When set to RPVST mode, the switch continues to run the common instance spanning tree (CIST) state machine on VLAN 1 by exchanging IEEE BPDUs with the legacy RSTP switches.

To successfully connect RSTP and RPVST domains, the system administrator must align the native VLAN configuration across all network switches, or in other words, the internal identification of untagged packets to VLAN.

STP Commands

spanning-tree

	spanning-tree no spanning-tree Globally enables spanning tree. The no form disables spanning tree.
Syntax Description	N/A
Default	Spanning tree is enabled
Configuration Mode	config
History	3.1.0000
Example	switch (config) # no spanning-tree
Related Commands	show spanning-tree
Notes

spanning-tree mode

	spanning-tree mode {mst \| rst \| rpvst} no spanning-tree mode Changes spanning tree mode. The no form of the command sets the parameter to its default value.
Syntax Description	mst	Multiple spanning tree
	rst	Rapid spanning tree
	rpvst	Rapid per-VLAN spanning tree
Default	rst
Configuration Mode	config
History	3.3.4150
Example
Related Commands	show spanning-tree
Notes	The number of VLANs supported by RPVST is 128

spanning-tree (timers)

	spanning-tree [forward-time <time in secs> \| hello-time <time in secs> \| max-age <time in secs>] no spanning-tree [forward-time \| hello-time \| max-age \| priority] Configures spanning tree timers. The no form of the command sets the timer to default.
Syntax Description	forward-time	Controls how fast a port changes its spanning tree state from Blocking state to Forwarding state Parameter range: 4-30 seconds
	hello-time	Determines how often the switch broadcasts its hello message to other switches when it is the root of the spanning tree Parameter range: 1-2 seconds
	max-age	Sets the maximum age allowed for the Spanning Tree Protocol information learnt from the network on any port before it is discarded Parameter range: 6-40 seconds
Default	forward-time: 15 seconds hello-time:2 seconds max-age: 20 seconds
Configuration Mode	config
History	3.1.0000
Example	switch (config) # spanning-tree forward-time
Related Commands	show spanning-tree
Notes	The following formula applies on the spanning tree timers: 2(ForwardTime -1)>=MaxAgeTime >= 2(Hello Time + 1)

spanning-tree port type (default global)

	spanning-tree port type {edge [bpdufilter \| bpduguard] \| network [bpduguard] \| normal [bpduguard]} default no spanning-tree port type default Configures all switch interfaces as edge/network/normal ports. These ports can be connected to any type of device. The no form of the command disables the spanning tree operation.
Syntax Description	edge	Assumes all ports are connected to hosts/servers
	bpdufilter	Configures to enable the spanning tree BPDU filter
	bpduguard	Configures to enable the spanning tree BPDU guard
	network	Assumes all ports are connected to switches and bridges
	normal	The port type (edge or network) determines according to the spanning tree operational mode
Default	normal
Configuration Mode	config
History	3.1.0000
History	3.4.0008	Updated command syntax
Example	switch (config) # spanning-tree port type edge default
Related Commands	show spanning-tree
Notes

spanning-tree priority

	spanning-tree priority <bridge-priority> no spanning-tree priority Sets the spanning tree bridge priority. The no form of the command sets the bridge priority to default.
Syntax Description	bridge-priority	Sets the bridge priority for the spanning tree Value must be in increments of 4096, starting from 0 (accepted values: 0, 4096, 8192, 12288, 16384, 20480, 24576, 28672, 32768, 36864, 40960, 45056, 49152, 53248, 57344, 61440)
Default	32786
Configuration Mode	config
History	3.1.0000
Example	switch (config) # spanning-tree priority 4096
Related Commands	show spanning-tree
Notes

spanning-tree port-priority

	spanning-tree port-priority <priority> no spanning-tree port-priority Configures the spanning-tree interface priority. The no form of the command returns configuration to its default.
Syntax Description	priority	Spanning tree interface priority Possible values: 0, 16, 32,48, 64, 80, 96, 112, 128,144, 160, 176, 192, 208, 224, 240
Default	128
Configuration Mode	config interface ethernet config interface port-channel config interface mlag-port-channel
History	3.1.0000
History	3.3.4500	Added MPO configuration mode
Example	switch (config interface ethernet 1/1) # spanning-tree port-priority 16
Related Commands	show spanning-tree
Notes

spanning-tree cost

	spanning-tree cost <port cost> no spanning-tree cost Configures the interface cost of the spanning tree. The no form of the command returns configuration to its default.
Syntax Description	port cost	Sets the spanning tree cost of an interface. Range: 0-200000000
Default	The default cost is derived from the interface speed: 1Gb/s 20000 10Gb/s 2000 40Gb/s 500 50Gb/s 400 100Gb/s 200
Configuration Mode	config interface ethernet config interface port-channel config interface mlag-port-channel
History	3.1.0000
History	3.3.4500	Added MPO configuration mode
Example	switch (config interface ethernet 1/1) # spanning-tree cost 1000
Related Commands	show spanning-tree
Notes	LAG default cost is calculated by dividing the port speed by the number of active links in UP state. For example: if there were 4 links in the LAG out of which only two are in UP state, assuming the port speed is 10Gbps, the LAG cost will be 2000/2 = 1000. When configuring the cost for a LAG, the cost will be fixed to this configuration, no matter what the number of active links (UP state) in the LAG is Unstable network may cause the LAG cost to change dynamically assuming the cost parameter is not configured for anything else other than default

spanning-tree port type

	spanning-tree port type <port type> no spanning-tree port type Configures spanning-tree port type The no form of the command returns configuration to default.
Syntax Description	default	According to global configuration.
	edge	Assumes all ports are connected to hosts/servers.
	normal	The port type (edge or network) determines according to the spanning tree operational mode.
	network	Assumes all ports are connected to switches and bridges.
	bpdufilter	Configures to enable the spanning tree BPDU filter.
	bpduguard	Configures to enable the spanning tree BPDU guard.
Default	Globally defined by the command “spanning-tree port type <port-type> default”.
Configuration Mode	config interface ethernet config interface port-channel config interface mlag-port-channel
History	3.1.0000
History	3.3.4500	Added MPO configuration mode
Example	switch (config interface ethernet 1/1) # spanning-tree port type edge
Related Commands	show spanning-tree
Notes

spanning-tree guard

	spanning-tree guard {loop \| root} no spanning-tree guard {loop \| root} Configures spanning-tree guard. The no form of the command returns configuration to default.
Syntax Description	loop	Enables loop-guard on the interface. If the loop-guard is enabled, upon a situation where the interface fails to receive BPDUs the switch will not egress data traffic on this interface.
Syntax Description	root	Enables root-guard on the interface. If root-guard is enabled on the interface, the interface will never be selected as root port.
Default	loop-guard and root-guard are disabled
Configuration Mode	config interface ethernet config interface port-channel config interface mlag-port-channel
History	3.1.0000
History	3.3.4500	Added MPO configuration mode
Example	switch (config interface ethernet 1/1) # spanning-tree guard root
Related Commands	show spanning-tree
Notes

spanning-tree bpdufilter

	spanning-tree bpdufilter {disable \| enable} no spanning-tree bpdufilter Configures spanning-tree BPDU filter on the interface. The interface will ignore any BPDU that it receives and will not send PDBUs, The STP state on the port will move to the forwarding state. The no form of the command returns the configuration to default.
Syntax Description	disable	Disables the BPDU filter on this port
Syntax Description	enable	Enables the BPDU filter on this port
Default	BPDU filter is disabled
Configuration Mode	config interface ethernet config interface port-channel config interface mlag-port-channel
History	3.1.0000
Example	switch (config interface ethernet 1/1) # spanning-tree bpdufilter enable
Related Commands	show spanning-tree
Notes	This command can be used when the switch is connected to hosts

clear spanning-tree counters

	clear spanning-tree counters Clears the spanning-tree counters.
Syntax Description	N/A
Default	N/A
Configuration Mode	config
History	3.1.0000
Example	switch (config) # clear panning-tree counters
Related Commands	show spanning-tree
Notes

spanning-tree mst max-hops

	spanning-tree mst max-hops <max-hops> no spanning-tree mst max-hops Specifies the max hop value inserts into BPDUs that sent out as the root bridge. The no form of the command sets the parameter to its default value.
Syntax Description	max-hops	Max hop value Range: 6-40
Default	20
Configuration Mode	config
History	3.3.4150
Example	switch (config) # spanning-tree mst max-hops 20
Related Commands	show spanning-tree
Notes	The max hop setting determines the number of bridges in an MST region that a BPDU can traverse before it is discarded This command is available when global STP mode is set to MST

spanning-tree mst priority

	spanning-tree mst <mst-instance> priority <priority> no spanning-tree mst <mst-instance> priority Configures the specified instance’s priority number. The no form of the command sets the parameter to its default value.
Syntax Description	mst-instance	MST instance Range: 1-64
Syntax Description	priority	MST instance port priority Value must be in increments of 4096, starting from 0 (accepted values: 0, 4096, 8192, 12288, 16384, 20480, 24576, 28672, 32768, 36864, 40960, 45056, 49152, 53248, 57344, 61440)
Default	32768
Configuration Mode	config
History	3.3.4150
Example	switch (config) # spanning-tree mst 1 priority 32768
Related Commands	show spanning-tree
Notes	The bridge priority is the four most significant digits of the bridge ID, which is used by spanning tree algorithms to select the root bridge and choose among redundant links. Bridge ID numbers range from 0-65535 (16 bits); bridges with smaller bridge IDs are elected over other bridges. This command is available when global STP mode is set to MST

spanning-tree mst vlan

	spanning-tree mst <mst-instance> vlan <vlan-id> no spanning-tree mst <mst-instance> vlan <vlan-id> Maps a VLAN or a range of VLANs into an MSTP instance. The no form of the command unmaps a VLAN or a range of VLANs from MSTP instances.
Syntax Description	mst-instance	MST instance Range: 1-64
Syntax Description	vlan-id	A single VLAN or a a range of VLANs Formats: “<vlan>” or “<from-vlan>-<to-vlan>” (see Example below)
Default	N/A
Configuration Mode	config
History	3.3.4150
Example	switch (config) # spanning-tree mst 1 vlan 10-20
Related Commands	show spanning-tree
Notes	This command is available when global STP mode is set to MST

spanning-tree mst revision

	spanning-tree mst revision <number> no spanning-tree mst revision Configures the MSTP revision number. The no form of the command sets the parameter to its default value.
Syntax Description	number	MST revision number Range: 0-65535
Default	0
Configuration Mode	config
History	3.3.4150
Example	switch (config)# spanning-tree mst revision 1
Related Commands	show spanning-tree
Notes	The revision number is one of three parameters, along with the MST name and VLAN-to-instance map, that identify the switch’s MST region This command is available when global STP mode is set to MST

spanning-tree mst name

	spanning-tree mst name <name> no spanning-tree mst name Configures the MSTP name. The no form of the command sets the parameter to its default value.
Syntax Description	name	MST name: Up to 32 characters
Default	N/A
Configuration Mode	config
History	3.3.4150
Example	switch (config)# spanning-tree mst name mymst
Related Commands	show spanning-tree
Notes	The name is one of three parameters, along with the MST revision number and VLAN-to-instance map, that identifies the switch’s MST region This command is available when global STP mode is set to MST

spanning-tree mst root

	spanning-tree mst <mst-instance> root <role> no spanning-tree mst <mst-instance> root Changes the bridge priority for the specified MST instance to the following values: Primary – 8192 Secondary – 16384 The no form of the command sets the parameter to its default value.
Syntax Description	mst-instance	MSTP instance Range: 1-64
Syntax Description	role	Possible values: “primary” or “secondary”
Default	primary
Configuration Mode	config
History	3.3.4150
History	3.7.1000	Updated example
Example	switch (config)# spanning-tree mst 1 root primary
Related Commands	show spanning-tree
Notes	The root command is a way to automate a system configuration while ‘playing’ with the priority field. The priority field granularity may be too explicit for some users in case you wish to have 2 levels of priority (primary and secondary). So by default all the switches get the same priority and while using the root option you can get the role of master and backup by setting the priority field to a predefined value. This command is available when global STP mode is set to MST

spanning-tree mst port-priority

	spanning-tree mst <mst-instance> port-priority <priority> no spanning-tree mode Changes the spanning tree mode. The no form of the command sets the parameter to its default value.
Syntax Description	mst-instance	MST instance Range: 1-64
Syntax Description	priority	MST instance port priority Valid values are: 0, 16, 32, 48, 64, 80, 96, 112, 128, 144, 160, 176, 192, 208, 224 and 240
Default	rst
Configuration Mode	config interface ethernet config interface port-channel
History	3.3.4150
Example	switch (config interface ethernet 1/1)# spanning-tree mst 1 port-priority 32768
Related Commands	show spanning-tree
Notes	This command is available when global STP mode is set to MST

spanning-tree mst cost

	spanning-tree mst <mst-instance> cost <cost-value> no spanning-tree mode Configures the cost per MSTP instance. The no form of the command sets the parameter to its default value.
Syntax Description	mst-instance	MST instance Range: 1-64
Syntax Description	cost-value	MST instance port cost Range: 0-200000000
Default	20000 for 1Gb/s 2000 for 10Gb/s 500 for 40Gb/s 357 for 56Gb/s 200 for 100Gb/s
Configuration Mode	config interface ethernet config interface port-channel
History	3.3.4150
Example	switch (config interface ethernet 1/1)# spanning-tree mst 1 cost 4000
Related Commands	show spanning-tree
Notes	This command is available when global STP mode is set to MST

spanning-tree vlan forward-time

	spanning-tree vlan <vid> forward-time <secs> no spanning-tree vlan <vid> forward-time Configures how fast an interface changes its spanning tree state from Blocking to Forwarding. The no form of the command resets the parameter value to its default.
Syntax Description	secs	Parameter range: 4-30 seconds.
Default	15 seconds
Configuration Mode	config
History	3.4.1100
Example	switch (config) # spanning-tree vlan 10 forward-time 15
Related Commands	show spanning-tree
Notes	The following formula applies on the spanning tree timers: 2(ForwardTime -1)>=MaxAgeTime >= 2(Hello Time + 1) This command is available when global STP mode is set to RPVST

spanning-tree vlan hello-time

	spanning-tree vlan <vid> hello-time <secs> no spanning-tree vlan <vid> hello-time Configures how often the switch broadcasts its hello message to other switches when it is the root of the spanning tree. The no form of the command resets the parameter value to its default.
Syntax Description	vid	VLAN ID
Syntax Description	secs	Range: 1-2 seconds
Default	2 seconds
Configuration Mode	config
History	3.4.1100
Example	switch (config) # spanning-tree vlan 10 hello-time 2
Related Commands	show spanning-tree
Notes	The following formula applies on the spanning tree timers: 2(ForwardTime -1)>=MaxAgeTime >= 2(Hello Time + 1) This command is available when global STP mode is set to RPVST

spanning-tree vlan max-age

	spanning-tree vlan <vid> max-age <secs> no spanning-tree vlan <vid> max-age Sets the maximum age allowed for the Spanning Tree Protocol information learned from the network on any port before it is discarded. The no form of the command resets the parameter value to its default.
Syntax Description	secs	Range: 6-40 seconds
Default	20 seconds
Configuration Mode	config
History	3.4.1100
Example	switch (config) # spanning-tree vlan 10 max-age 20
Related Commands	show spanning-tree
Notes

spanning-tree vlan priority

	spanning-tree vlan <vid> priority <priority> no spanning-tree vlan <vid> priority Configures RPVST instance port priority. The no form of the command resets the parameter value to its default.
Syntax Description	vid	VLAN ID
Syntax Description	priority	MST instance port priority Value must be in increments of 4096, starting from 0 (accepted values: 0, 4096, 8192, 12288, 16384, 20480, 24576, 28672, 32768, 36864, 40960, 45056, 49152, 53248, 57344, 61440)
Default	32768
Configuration Mode	config
History	3.4.1100
Example	switch (config) # spanning-tree vlan 10 priority 32768
Related Commands	show spanning-tree
Notes

show spanning-tree

	show spanning-tree Displays spanning tree information.
Syntax Description	N/A
Default	N/A
Configuration Mode	Any command mode
History	3.1.0000
	3.4.1100	Updated example with R and G flags
	3.6.6000	Updated example
	3.6.6102	Added note on MLAG spanning-tree cost
Example
switch (config) # show spanning-tree Switch : ethernet-default Spanning tree protocol rst : enabled Spanning tree force version: 2 Root ID: Priority: 32768 Address : 7c:fe:90:ff:2c:40 This bridge is the root Hello Time (sec) : 2 Max Age (sec) : 20 Forward Delay (sec): 15 Bridge ID: Priority : 32768 Address : 7c:fe:90:ff:2c:40 Hello Time (sec) : 2 Max Age (sec) : 20 Forward Delay (sec): 15 L: Loop Inconsistent R: Root Inconsistent G: BPDU Guard Inconsistent ----------------------------------------------------------------------- Interface Role Sts Cost Prio Type ----------------------------------------------------------------------- Eth1/7 Designated Discarding 200 128 normal Eth1/8 Disabled Discarding(G) 200 128 edge
Related Commands	clear spanning-tree counters spanning-tree
Notes	MLAG spanning-tree cost is always equal to the cost of there being 2 member ports in the MLAG (even if one of the member ports fails or a new port is added) If a port is in BPDU Guard inconsistent mode, the interface status will move to "down (suspended)".

show spanning-tree detail

	show spanning-tree detail Displays detailed spanning-tree configuration and statistics.
Syntax Description	N/A
Default	N/A
Configuration Mode	Any command mode
History	3.1.0000
	3.6.4110	Updated example
	3.6.5000	Updated example
Example
Related Commands	clear spanning-tree counters spanning-tree
Notes

show spanning-tree interface

	show spanning-tree interface {ethernet <slot>/<port> \| port-channel <port-channel> \| mlag-port-channel <mlag-port-channel> Display running state for specific interfaces.
Syntax Description	ethernet	Ethernet interface
	port-channel	LAG instance
	mlag-port-channel	MLAG instance
Default	N/A
Configuration Mode	Any command mode
History	3.3.4150
Example	switch (config) # show spanning-tree 1/2 Eth1/2 is Disabled Discarding Port path cost 500, Port priority 128, Port Identifier 128.5 Designated root has priority 0, address unknown Designated bridge has priority 0, address unknown Designated port id 0.0, designated path cost 0 Number of transitions to forwarding state: 0 Port type: normal PortFast is: off Bpdu filter: disabled Bpdu guard: disabled Loop guard: disabled Root guard: disabled Link type: point-to-point BPDU: sent: 0 received: 0
Related Commands	clear spanning-tree counters spanning-tree
Notes

show spanning-tree mst

	show spanning-tree mst [details \| <instance> interface {ethernet <slot>/<port> \| port-channel <port-channel> \| mlag-port-channel <mlag-port-channel>}] Displays basic multi-spanning-tree information.
Syntax Description	details	Displays detailed multi-spanning-tree configuration and statistics
	ethernet	Ethernet interface
	port-channel	LAG instance
	mlag-port-channel	MLAG instance
Default	N/A
Configuration Mode	Any command mode
History	3.3.4150
History	3.6.6000	Updated example
Example
switch (config) # switch (config) # show spanning-tree mst MST0: vlans mapped: 1-1023,1025-2047,2049-3071,3073-4094 L: Loop Inconsistent R: Root Inconsistent G: BPDU Guard Inconsistent ----------------------------------------------------------------------- Interface Role Sts Cost Prio Type ----------------------------------------------------------------------- Eth1/7 Designated Discarding 200 128.7 normal Eth1/8 Disabled Discarding(G) 200 128.8 edge
Related Commands	clear spanning-tree counters spanning-tree
Notes

show spanning-tree root

	show spanning-tree root Displays root multi-spanning-tree information.
Syntax Description	N/A
Default	N/A
Configuration Mode	Any command mode
History	3.3.4150
Example
switch (config) # show spanning-tree root Instance Priority MAC addr Root Cost Hello Time Max Age FWD Dly Root Port ------- ------ -------- --------- ---------- -------- ------- --------- MST0 32768 00:02:c9:71:ed:40 500 2 20 15 Eth1/20 MST1 32768 00:02:c9:71:f0:c0 0 2 20 15 - MST2 0 00:02:c9:71:f0:c0 0 2 20 15 - MST3 32768 00:02:c9:71:f0:c0 0 2 20 15 -
Related Commands	clear spanning-tree counters spanning-tree
Notes

show spanning-tree vlan

	show spanning-tree vlan <vid> [detail \| interface {ethernet <slot>/<port> \| port-channel <port-channel> \| mlag-port-channel <mlag-port-channel>}] Displays spanning-tree protocol information.
Syntax Description	vid	VLAN ID. Range is also supported Format: <vid1>[-<vid2>]
	detail	Displays detailed RPVST configuration and statistics
	ethernet	Ethernet interface
	port-channel	LAG instance
	mlag-port-channel	MLAG instance
Default	N/A
Configuration Mode	Any command mode
History	3.4.1100
History	3.6.5000	Updated example output
Example
switch (config) # show spanning-tree vlan 1 detail Switch ethernet-default Spanning tree protocol is enabled Bridge is executing the rpvst compatible Spanning Tree Protocol Vlan 1: Bridge Identifier priority: 32769 Bridge Identifier address: e4:1d:2d:3d:5e:c0 Configured hello time: 2, max age 20, forward delay 15 Current root: priority 32769, address e4:1d:2d:3d:5e:c0 Number of topology changes: 0, last change occurred 00:00:00 ago Last TCN received from: N/A Timers: hold 6 hello 2, max age 20, forward delay 15 Default port type: normal Default bpdu filter: disabled Default bpdu guard: disabled
Related Commands	clear spanning-tree counters spanning-tree
Notes

show spanning-tree vlan topo-change-history

	show spanning-tree vlan <vid> topo-change-history Displays spanning-tree topology change notification history per VLAN.
Syntax Description	vid	VLAN ID Format: <vid1>[-<vid2>]
Default	N/A
Configuration Mode	Any command mode
History	3.6.4110
Example	switch (config) # show spanning-tree vlan 50 topo-change-history Vlan 50 ------------------------------------- Interface Date Time ------------------------------------- Eth1/49 07/18/17 04:39:58 Eth1/49 07/18/17 04:39:55 Eth1/49 07/18/17 04:38:11 Eth1/49 07/18/17 04:38:09
Related Commands	spanning-tree
Notes

show spanning-tree mst topo-change-history

	show spanning-tree mst <mst-instance> topo-change-history Displays spanning-tree topology change notification history per instance.
Syntax Description	mst-instance	MST instance Range: 1-64
Default	N/A
Configuration Mode	Any command mode
History	3.6.4110
Example	switch (config) # show spanning-tree mst 5 topo-change-history Instance 5 ------------------------------------- Interface Date Time ------------------------------------- Eth1/49 07/18/17 04:43:51 Eth1/49 07/18/17 04:43:33
Related Commands	spanning-tree
Notes

show spanning-tree topo-change-history

	show spanning-tree topo-change-history Displays spanning-tree topology change notification history.
Syntax Description	mst-instance	MST instance Range: 1-64
Default	N/A
Configuration Mode	Any command mode
History	3.6.4110
Example	switch (config) # show spanning-tree topo-change-history ------------------------------------- Interface Date Time ------------------------------------- Eth1/49 07/27/17 09:39:38 Eth1/35 07/27/17 09:35:42 Eth1/35 07/27/17 09:35:40 Eth1/35 07/27/17 09:35:08 Eth1/35 07/27/17 09:35:06 Eth1/35 07/27/17 09:32:05 Eth1/35 07/27/17 09:32:03 Eth1/35 07/27/17 09:31:42 Eth1/35 07/27/17 09:31:40
Related Commands	spanning-tree
Notes

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