What is spanning-tree root protect?
Root guard is an STP feature that is enabled on a port-by-port basis; it prevents a configured port from becoming a root port. Root guard prevents a downstream switch (often misconfigured or rogue) from becoming a root bridge in a topology. Root guard is enabled with the interface command spanning-tree guard root.
What is the purpose of STP BPDUs?
In a Layer 2 bridge environment, spanning-tree protocols use data frames called Bridge Protocol Data Units (BPDUs) to exchange information among bridges. Spanning-tree protocols on peer systems exchange BPDUs, which contain information about port roles, bridge IDs, and root path costs.
What is the difference between STP BPDU Guard and STP root guard?
BPDU Guard: Prevents accidental connection of switching devices to PortFast-enabled ports. BPDU filtering: Restricts the switch from sending unnecessary BPDUs out access ports. Root Guard: Prevents switches connected on ports configured as access ports from becoming. the root switch.
What protection does BPDU Guard provide?
BPDU Guard feature protects the port from receiving STP BPDUs, however the port can transmit STP BPDUs. When a STP BPDU is received on a BPDU Guard enabled port, the port is shutdown and the state of the port changes to ErrDis (Error-Disable) state.
What are the two reasons to use Root Guard?
The root guard feature provides a way to enforce the root bridge placement in the network. The root guard ensures that the port on which root guard is enabled is the designated port. Normally, root bridge ports are all designated ports, unless two or more ports of the root bridge are connected together.
How do I set root guard?
Configure the Root Guard
- Enter Configuration mode for the interface. SEFOS# configure terminal SEFOS(config)# interface extreme-ethernet 0/1.
- Configure the port as a trunk port.
- Enable the root guard on the port.
- Review the root guard output on the port.
- Disable the root guard on the interface.
What is BPDU STP?
(Bridge Protocol Data Unit) A spanning tree protocol (STP) message unit that describes the attributes of a switch port such as its MAC address, priority and cost to reach. BPDUs enable switches that participate in a spanning tree protocol to gather information about each other.
How does loop guard work?
The loop guard feature makes additional checks. If BPDUs are not received on a non-designated port, and loop guard is enabled, that port is moved into the STP loop-inconsistent blocking state, instead of the listening / learning / forwarding state. The port moves to the STP forwarding state and creates a loop.
What is difference between BPDU guard and BPDU filter?
BPDU filter will prevent inbound and outbound BPDU but will remove portfast state on a port if a BPDU is received. On the other hand, BPDU Guard keeps an eye open for any BPDU’s entering the interfaces that are enabled this feature. The port will disable as soon as the first BPDU is received, by shutting the port down.
Where do I turn in BPDU guard?
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.
What is root guard used for?
How does the root guard work in BPDU?
The Root Guard feature prevents a Designated Port from becoming a Root Port. If a port on which the Root Guard feature receives a superior BPDU, it moves the port into a root-inconsistent state (effectively equal to a listening state), thus maintaining the current Root Bridge status.
When to use BPDU protection for spanning-tree protocols?
When BPDUs generated by other devices are transmitted to switches on which spanning-tree protocols are configured, a misconfiguration can occur in the spanning tree and a network outage can occur. Therefore, it is necessary to protect an interface in a spanning-tree topology from BPDUs generated from other devices.
How does backbonefast work in BPDU spanning tree?
BackboneFast allows the blocked port on Switch C to move immediately to the listening state without waiting for the maximum aging time for the port to expire. BackboneFast then transitions the port on Switch C to the forwarding state, providing a path from Switch B to Switch A. This switchover takes approximately 30 seconds.
Which is a feature of spanning-tree root guard?
This is another (short) post about three more important features of spanning-tree, as discussed on my previous blog. Spanning-tree root guard is useful in avoiding layer 2 loops during network anomalies. Root guard forces an interface to become a designated port to prevent switches from becoming a root switch.