What is spanning-tree loopback guard?
1)LoopGuard: Spanning Tree Loop Guard helps to prevent loops when you use fibre links. Fibre links have a transmit and receive connector. If one of these links fails it’s possible that interfaces that are currently in “blocking” mode go to forwarding. This might cause a loop.
What does spanning-tree Bpduguard enable?
BPDU Guard feature is used to protect the Layer 2 Spanning Tree Protocol (STP) Topology from BPDU related attacks. When a BPDU Guard enabled port receive BPDU from the connected device, BPDU Guard disables the port and the port state is changed to Errdisable state.
How do I enable Bpduguard?
The BPDU guard feature can be globally enabled on the switch or can be enabled per interface, but the feature operates with some differences. 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.
How do I enable UplinkFast?
To enable UplinkFast on a VLAN with switch priority configured, first restore the switch priority on the VLAN to the default value by using the no spanning-tree vlan vlan-id priority global configuration command. UplinkFast on an individual VLAN. The UplinkFast feature is supported only when the switch is running PVST.
What does loop guard do?
Loopguard provides additional protection against Layer 2 forwarding loops (spanning tree loops). A spanning tree loop is created when a spanning tree blocking port, in a redundant topology, erroneously transitions to the forwarding state. Best practices is that loopguard be used on non-designated ports.
Where do you put a loop guard?
Loop guard must be enabled on the non-designated ports (more precisely, on root and alternate ports) for all possible combinations of active topologies. As long as the loop guard is not a per-VLAN feature, the same (trunk) port might be designated for one VLAN and non-designated for the other.
What is Loop Guard?
How do I know if my BPDU Guard is enabled?
To display the BPDU guard state, enter the show running configuration or the show stp-bpdu-guard command. For the BPDU status enter the stp-bpdu-guard command.
What is UplinkFast and BackboneFast?
UplinkFast works by finding alternate ports for directly connected links. Similarly BackboneFast works on finding an alternate path when an indirect link to the root port goes down.
What is UplinkFast in switch?
UplinkFast provides the immediate shift to alternate port by determining the possible paths going to the Root Switch (Root Bridge). The collection of possible paths going to the Root Switch (Root Bridge) are called uplink group.
What is Udld aggressive?
With UDLD aggressive mode enabled, when a port on a bidirectional link that has a UDLD neighbor relationship established stops receiving UDLD packets, UDLD tries to reestablish the connection with the neighbor. After eight failed retries, the port is disabled.
What is loop protection?
Loop protection increases the efficiency of STP, RSTP, and MSTP by preventing ports from moving into a forwarding state that would result in a loop opening up in the network. When loop protection is enabled, the spanning-tree topology detects root ports and blocked ports and makes sure both keep receiving BPDUs.
How to enable or disable loop guard in spanning tree?
The possible failover scenarios should also be taken into account. By default, loop guard is disabled. This command is used to enable loop guard: set spantree guard loop Console> (enable) set spantree guard loop 3/13 Enable loopguard will disable rootguard if it’s currently enabled on the port (s).
Can you enable loop guard on a per port basis?
You can enable loop guard on a per-port basis. When you enable loop guard, it is automatically applied to all of the active instances or VLANs to which that port belongs. When you disable loop guard, it is disabled for the specified ports.
What does portfast do in spanning tree guard?
PortFast causes a switch or trunk port to enter the spanning tree forwarding state immediately, bypassing the listening and learning states. You can use PortFast on switch or trunk ports that are connected to a single workstation, switch, or server to allow those devices to connect to the network immediately, instead of waiting for the port to
When does a port enter the spanning tree listening state?
If you enable PortFast on a port that is connected to another Layer 2 device, such as a switch, you might create network loops. When the switch powers up, or when a device is connected to a port, the port enters the spanning tree listening state. When the Forward Delay timer expires, the port enters the learning state.