Dell Command Line Reference Guide for the S4048–ON System 9.14.2.5

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spanning-tree pvst

Configure a PVST+ interface with one of these settings: edge port with optional bridge port data unit (BPDU) guard, port disablement if an error condition occurs, port priority or cost for a VLAN range, loop guard, or root guard.

S4048

Syntax
spanning-tree pvst {edge-port [bpduguard [shutdown-on-violation]] | err-disable | vlan vlan-range {cost number | priority value} | loopguard | rootguard}
Parameters
edge-port
Enter the keywords edge-port to configure the interface as a PVST+ edge port.
bpduguard

Enter the keyword portfast to enable Portfast to move the interface into Forwarding mode immediately after the root fails.

Enter the keyword bpduguard to disable the port when it receives a BPDU.

shutdown-on-violation
(OPTIONAL) Enter the keywords shutdown-on-violation to hardware disable an interface when a BPDU is received and the port is disabled.
err-disable
Enter the keywords err-disable to enable the port to be put into the error-disable state (EDS) if an error condition occurs.
vlan vlan-range
Enter the keyword vlan then the VLAN numbers. The range is from 1 to 4094.
cost number
Enter the keyword cost then the port cost value. The range is from 1 to 200000.
Defaults:
  • 100 Mb/s Ethernet interface = 200000.
  • 1-Gigabit Ethernet interface = 20000.
  • 10-Gigabit Ethernet interface = 2000.
  • Port Channel interface with one 100 Mb/s Ethernet = 200000.
  • Port Channel interface with one 1 Gigabit Ethernet = 20000.
  • Port Channel interface with one 10 Gigabit Ethernet = 2000.
  • Port Channel with two 1 Gigabit Ethernet = 18000.
  • Port Channel with two 10 Gigabit Ethernet = 1800.
  • Port Channel with two 100 Mbps Ethernet = 180000.
priority value
Enter the keyword priority then the Port priority value in increments of 16. The range is from 0 to 240. The default is 128.
loopguard
(C-, S-, and E-Series only) Enter the keyword loopguard to enable loop guard on a PVST+ port or port-channel interface.
rootguard
(C-, S-, and E-Series only) Enter the keyword rootguard to enable root guard on a PVST+ port or port-channel interface.
Defaults
Not configured.
Command Modes
INTERFACE
Command History

This guide is platform-specific. For command information about other platforms, see the relevant Dell EMC Networking OS Command Line Reference Guide.

Version
Description
9.10(0.1)
Introduced on the S6010-ON and S4048T-ON.
9.10(0.0)
Introduced on the S3148.
9.10(0.0)
Introduced on the S6100-ON.
9.8(2.0)
Introduced on the S3100 series.
9.8(1.0)
Introduced on the Z9100-ON.
9.8(0.0P5)
Introduced on the S4048-ON.
9.8(0.0P2)
Introduced on the S3048-ON.
9.7(0.0)
Introduced on the S6000-ON.
9.2(1.0)
Introduced on the Z9500.
9.0.2.0
Introduced on the S6000.
8.3.19.0
Introduced on the S4820T.
8.3.11.1
Introduced on the Z9000.
8.4.2.1
Introduced the loopguard and rootguard options on the E-Series, C-Series, and S-Series.
8.3.7.0
Introduced on the S4810.
8.2.1.0
Introduced the hardware shutdown-on-violation option.
7.6.1.0
Introduced on the S-Series.
7.5.1.0
Introduced on the C-Series.
7.4.1.0
Added the optional Bridge Port Data Unit (BPDU) guard.
6.2.1.1
Introduced.
Usage Information

The BPDU guard option prevents the port from participating in an active STP topology in case a BPDU appears on a port unintentionally, or is misconfigured, or is subject to a DOS attack. This option places the port into the Error Disable state if a BPDU appears, and a message is logged so that the administrator can take corrective action.

NOTE: A port configured as an edge port, on a PVST switch, immediately transitions to the forwarding state. Only ports connected to end-hosts should be configured as an edge port. Consider an edge port similar to a port with a spanning-tree portfast enabled.

If you do not enable shutdown-on-violation, BPDUs are still sent to the route process module (RPM) CPU.

You cannot enable root guard and loop guard at the same time on a port. For example, if you configure loop guard on a port on which root guard is already configured, the following error message is displayed: % Error: RootGuard is configured. Cannot configure LoopGuard.

When used in a PVST+ network, loop guard is performed per-port or per-port channel at a VLAN level. If no BPDUs are received on a VLAN interface, the port or port-channel transitions to a Loop-Inconsistent (blocking) state only for this VLAN.

Enabling Portfast BPDU guard and loop guard at the same time on a port results in a port that remains in a Blocking state and prevents traffic from flowing through it. For example, when Portfast BPDU guard and loop guard are both configured:
  • If a BPDU is received from a remote device, BPDU guard places the port in an Err-Disabled Blocking state and no traffic is forwarded on the port.
  • If no BPDU is received from a remote device, loop guard places the port in a Loop-Inconsistent Blocking state and no traffic is forwarded on the port.
Example
DellEMC(conf-if-te-1/1)# spanning-tree pvst vlan 3 cost 1800
DellEMC(conf-if-te-1/1)# end
DellEMC(conf-if-te-1/1)# show config
!
interface TenGigabitEthernet 1/1
  no ip address
  switchport
  spanning-tree pvst vlan 3 cost 1800
  no shutdown
DellEMC(conf-if-te-1/1)# end

DellEMC#
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