What does spanning-tree Portfast default do?
What does spanning-tree Portfast default do?
The spanning-tree portfast default global configuration mode command enables PortFast on all non-trunking interfaces. To configure BPDU guard on a Layer 2 access port, use the spanning-tree bpduguard enable interface configuration mode command, as shown in Example 3-6.
What does enabling Portfast on a Switchport do?
Enabling the PortFast feature causes a switch or a trunk port to enter the STP forwarding-state immediately or upon a linkup event, thus bypassing the listening and learning states. The PortFast feature is enabled at a port level, and this port can either be a physical or a logical port.
What is spanning-tree Portfast command?
Portfast feature causes a switch port to enter the spanning tree forwarding state immediately, bypassing the listening and learning states.
What is the purpose of the Spanning Tree Protocol STP )?
The Spanning Tree Protocol (STP) is a network protocol that builds a loop-free logical topology for Ethernet networks. The basic function of STP is to prevent bridge loops and the broadcast radiation that results from them.
When should I disable spanning-tree?
The most common reason for disabling spanning tree is that the original 802.1D Spanning Tree Protocol (STP) goes through a fairly lengthy wait period from the time a port becomes electrically active to when it starts to pass traffic.
What is Ethernet channel in Cisco?
EtherChannel is a port link aggregation technology or port-channel architecture used primarily on Cisco switches. It allows grouping of several physical Ethernet links to create one logical Ethernet link for the purpose of providing fault-tolerance and high-speed links between switches, routers and servers.
When should PortFast be set up?
Any port that is directly connected to an end station cannot create bridging loops. Therefore, the port can rapidly transition to the forwarding state by skipping the learning and listening states.
Which commands can be used to enable PortFast on a switch?
BPDU guard can be enabled on all PortFast-enabled ports by using the spanning-tree portfast bpduguard default global configuration command. Alternatively, BPDU guard can be enabled on a PortFast-enabled port through the use of the spanning-tree bpduguard enable interface configuration command.
Should I use spanning-tree Portfast?
PortFast feature should be used only to connect a single workstation to a switch port to avoid layer 2 switching loop. Spanning Tree PortFast feature causes a port to enter the forwarding state immediately, bypassing the listening and learning states.
What is spanning-tree Portfast Bpduguard default?
Understanding BPDU Guard At the global level, you enable BPDU guard on Port Fast-enabled STP ports by using the spanning-tree portfast bpduguard default global configuration command. Spanning tree shuts down STP ports that are in a Port Fast-operational state if any BPDU is received on those ports.
How to enable spantree portfast BPDU-guard?
Console> (enable) set spantree portfast bpdu-guard enable Spantree portfast bpdu-guard enabled on this switch. Console> (enable) When STP BPDU guard disables the port, the port remains in the disabled state unless the port is enabled manually. You can configure a port to reenable itself automatically from the errdisable state.
How do I check if the spantree feature is enabled or disabled?
In order to verify whether the feature is enabled or disabled, issue this command: Console> (enable) show spantree summary Root switch for vlans: 3-4. Portfast bpdu-guard enabled for bridge. Uplinkfast disabled for bridge. Backbonefast disabled for bridge.
What is the difference between spanning tree and uplinkfast?
By default, spanning tree sends BPDUs from all ports regardless of whether PortFast is enabled. BDPU filtering is on a per-switch basis; after you enable BPDU filtering, it applies to all PortFast-enabled ports on the switch. UplinkFast provides fast convergence using uplink groups in the network access layer after a spanning tree topology change.
What happens when you enable portfast on the switch?
When you enable PortFast on the switch, spanning tree places ports in the forwarding state immediately, instead of going through the listening, learning, and forwarding states. By default, spanning tree sends BPDUs from all ports regardless of whether PortFast is enabled.
