Spanning Tree Protocol

NVIDIA MLNX-GW User Manual for NVIDIA Skyway Appliance v8.2.2200

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.

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 has the following configuration options:

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

    Warning

    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:

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 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 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.

Warning

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

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

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.

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.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.

Warning

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.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.

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

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

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

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

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.

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

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

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

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

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

role

Possible values: “primary” or “secondary”

Default

primary

Configuration Mode

config

History

3.3.4150

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

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

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

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

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

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

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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