2.5 Rapid PVST+ Spanning Tree Protocol Flashcards
Interpret basic operations of Rapid PVST+ Spanning Tree Protocol, including root port, root bridge, other port names, port states, PortFast, root guard, loop guard, BPDU filter, and BPDU guard. (19 cards)
What are the benefits of using Rapid PVST+ over standard PVST+?
- Faster convergence.
- Better protection against topology changes.
- Efficient network resource usage.
Rapid PVST+ offers significantly faster network recovery after a failure and is better suited for large-scale or dynamic networks.
What is a Root Port in Rapid PVST+?
The port on a non-root bridge with the best path to the root bridge.
The Root Port forwards traffic toward the Root Bridge. Non-root bridges select this port based on the lowest path cost.
How is the Root Port selected in Rapid PVST+?
Based on the lowest path cost to the Root Bridge.
A switch will choose the path with the lowest cost (sum of port costs) to reach the Root Bridge.
What is a backup port that becomes active if the Root Port fails?
Alternate
The Alternate Port is used in Rapid PVST+ to improve convergence by providing a path to the root bridge if the primary Root Port becomes unavailable.
What refers to the central switch in Rapid PVST+ spanning tree topology?
Root Bridge
The Root Bridge is selected by the lowest bridge ID, and all other switches calculate paths to it in the spanning tree topology.
What is a Primary Root Bridge?
The initially elected Root Bridge in the network.
The Primary Root Bridge is selected based on the lowest bridge priority and MAC address.
True or False:
The Secondary Root Bridge acts as a backup to the Primary Root Bridge.
True
The Secondary Root Bridge is selected as the next best candidate if the Primary Root Bridge is lost.
What are the different port states in Rapid PVST+?
- Forwarding
- Blocking
Forwarding ports actively send and receive traffic, while Blocking ports prevent traffic to avoid network loops.
Why is the Forwarding port state used in Rapid PVST+?
It allows the port to send and receive network traffic.
Ports in the Forwarding state are actively forwarding traffic as part of the network topology.
Why is the Blocking port state used in Rapid PVST+?
It prevents a port from forwarding traffic to avoid network loops.
A Blocking port doesn’t participate in the data forwarding process to maintain a loop-free topology.
True or False:
PortFast allows a port to transition immediately to the Forwarding state.
True
PortFast is typically used to reduce the time it takes for devices to begin communicating when powered on.
What type of port should be configured with PortFast?
Access
PortFast is used on access ports that connect to end devices like computers or printers to reduce the delay in moving to the Forwarding state.
Fill in the blank:
_____ _____ prevents non-root bridges from becoming the Root Bridge.
Root Guard
It ensures only the designated Root Bridge can serve as the root by blocking BPDUs from unauthorized switches.
What is Loop Guard in Rapid PVST+?
It prevents a port from forwarding if the root path is lost.
This feature prevents network loops by blocking ports that might be misconfigured or vulnerable to looping.
What are the functions of BPDU Guard and BPDU Filter in Rapid PVST+?
- BPDU Guard: Disables a port if it receives a BPDU.
- BPDU Filter: Prevents a port from sending or receiving BPDUs.
BPDU (Bridge Protocol Data Unit) Guard is used on PortFast-enabled ports to prevent unauthorized switches from affecting the spanning tree. BPDU Filter suppresses BPDUs on access ports where spanning tree participation isn’t needed.
What are the key BPDU timers in Rapid PVST+?
- Hello Time
- Max Age
- Forward Delay
Hello Time: Determines how often BPDUs are sent.
Max Age: Defines how long a switch waits before considering a topology change.
Forward Delay: Specifies how long a port remains in a transitional state before becoming active.
True or False:
The Root Bridge has no Root Port in Rapid PVST+.
True
The Root Bridge does not need a Root Port because it is the reference point for all other bridges in the topology.
What is the role of the Designated Port in Rapid PVST+?
It forwards traffic to and from the root bridge on a segment.
The Designated Port is selected on each switch to manage traffic between the switch and the Root Bridge for specific network segments.
True or False:
The Designated Port is always on the Root Bridge.
False
The Designated Port is selected for each segment to forward traffic towards the Root Bridge, but it doesn’t have to be on the Root Bridge.
