52 Questions
What becomes a critical business concern as businesses become increasingly dependent on the network?
Network availability
What is the primary solution for achieving the necessary availability in network infrastructure?
Redundancy
How does Layer 2 redundancy improve network availability?
By implementing alternate network paths by adding equipment and cabling
What allows for a single path to be disrupted without impacting the connectivity of devices on the network?
Having multiple paths for data to traverse the network
What can happen when multiple paths exist between two devices on the network and STP is disabled?
Layer 2 loop
What prevents Layer 2 loops when STP is enabled on switches?
Loop avoidance by blocking redundant paths
STP id enabled by default on switches running layer 2, and this prevents layer 2 loops and duplicates frames.
True
What is the primary function of the Spanning Tree Protocol (STP)?
To ensure a single logical path between all destination at the network by blocking redundant paths which cause loops
How do switches running STP compensate for failures?
By dynamically unblocking previously blocked ports to allow alternate paths.
What is the role of a root bridge(single switch) in STP?
It serves as the reference point for all calculations
How are root ports determined in STP?
They are the switch ports closest to the root bridge
What is the specific role of a Designated Port in a Spanning Tree Protocol (STP) network?
Permits all non-root ports to forward of traffic on the network
What is the primary function of non-designated ports in a Spanning Tree Protocol (STP) ?
configures ports to be in a blocking state to prevent loops
How does Spanning Tree Protocol (STP) determine which switch ports need to be configured for blocking to prevent loops in a network?
Using the Spanning Tree Algorithm (STA)
What is the role of the Spanning Tree Algorithm (STA) in selecting a root bridge as a reference point for all calculations?
It designates a single switch as the root bridge using an election process.
The election process is controlled by the Bridge-ID (BID).
True
By default, what determines the root bridge in a Spanning Tree Protocol (STP) network?
The lowest MAC address of switch in the network.
How can the default selection of the root bridge be changed in STP?
By configuring the bridge priority.
Highest bridge priority configured is root bridge
False
What are the port roles on the root bridge in STP?
All ports are designated ports.
What is the role of ports on non-root bridges connected to the root bridge in STP?
All are root ports.
What are the ports connected to designated ports that are not root ports known as in STP?
Non-designated ports.
Speed of ports also used to calculate link cost back to root bridge.
True
The root bridge is elected for the spanning-tree instance.
True
In a network topology, what determines the calculation of port roles?
The location of the root bridge
What is the function of a root port in a network switch?
Determines the best path to forward traffic to the root bridge
What defines a designated port in an STP topology?
A port that receives and forwards frames toward the root bridge.
How many designated ports are permitted per segment in a network?
One
What is a non-designated port in STP?
A port that is in blocking state.
Which of the following are states that a port on a network switch can be in?
Listening, learning, forwarding, blocking, disabled
What is the function of a port in "Blocking" state in a network?
It is a non-designated port and does not participate in frame forwarding.
What does it mean when a port is in the "Listening" state in Spanning Tree Protocol (STP)?
STP has determined that the port can participate in frame forwarding based on received BPDU frames the switch received.
What occurs when a port is in the "Learning" state in a network switch?
The port prepares to participate in frame forwarding and begins to populate the MAC address table.
What is the characteristic of a port in the "Forwarding" state in a network switch?
The port is considered part of the active topology, forwards frames, and also sends and receives BPDU frames.
What is the characteristic of a port in the "Disabled" state in a network switch?
The Layer 2 port does not participate in STP and does not forward frames.
Which of the following accurately describe STP convergence? Select all 2 that apply (A)The time it takes for the network to set switch ports to their final spanning-tree port roles where all potential loops are eliminated. (B)The time it takes for the network to propagate the changes to all switches in the network. (C)The time it takes for the network to determine which switch is going to assume the role of the root bridge. (D)The time it takes for the network to elect the Designated and Non-designated ports.
A, C
What are the three steps in STP convergence?
Elect a root bridge, elect the root ports, elect the Designated and Non-designated ports.
What is true about the election process in a broadcast domain in STP?
All switches in the broadcast domain participate.
What occurs after a switch boots regarding Bridge Protocol Data Units (BPDU) frames?
The switch sends out BPDU frames containing the switch BID and the root ID every 2 seconds.
What does the root ID identify in a network topology?
The root bridge on the network.
What is the default behavior regarding the root ID and the local BID for switches on a network?
The root ID matches the local BID for all switches on the network, meaning each switch considers itself as the root bridge when it boots.
What happens as switches forward their Bridge Protocol Data Unit (BPDU) frames in the election process?
Switches in the broadcast domain read the root ID information from the BPDU frame.
What action does a receiving switch take if the root ID from the Bridge Protocol Data Unit (BPDU) received is lower than its own root ID?
The switch updates its root ID, identifying the adjacent switch as the root bridge.
What action does a switch take after updating its root ID when receiving a BPDU with a lower root ID?
The switch forwards new BPDU frames with the lower root ID to the other adjacent switches.
What happens at the end in the Spanning Tree Protocol (STP) process regarding the identification of the root bridge?
The switch with the lowest BID is identified as the root bridge for the spanning-tree instance.
How can the cost of a path in Spanning Tree Protocol (STP) be managed to specify a preferred path?
By manually configuring the cost of the path to ensure it's the preferred path instead of relying on STP's automatic selection.
How does changing the cost of a particular path affect the Spanning Tree Algorithm (STA)?
It may influence the STA's decision-making process, potentially favoring the path with the adjusted cost.
What is the 'no' form of a command that returns the cost to its default value in Spanning Tree Protocol (STP)?
'no cost'
What command is used to set the cost to a specific value in Spanning Tree Protocol (STP) configuration?
spanning-tree cost [value]
What is the bridge priority in Spanning Tree Protocol (STP)?
A customizable value that you can use to influence which switch becomes the root bridge.
How is the root bridge determined in Spanning Tree Protocol (STP) based on switch priorities?
The switch with the lowest priority, which means lowest Bridge ID (BID), becomes the root bridge.
The lower the priority value, the higher the priority.
True
Study Notes
Network Availability and Redundancy
- As businesses become increasingly dependent on the network, network availability becomes a critical business concern.
- The primary solution for achieving necessary availability in network infrastructure is Layer 2 redundancy.
Spanning Tree Protocol (STP)
- STP is enabled by default on switches running Layer 2, preventing Layer 2 loops and duplicate frames.
- The primary function of STP is to prevent network loops and ensure network availability.
- STP compensates for failures by rerouting traffic through alternate paths.
- A root bridge (single switch) is elected as a reference point for all STP calculations.
- The root bridge is determined by the Bridge-ID (BID), with the lowest BID becoming the root bridge.
- The default selection of the root bridge can be changed by configuring a lower priority on a specific switch.
- The Spanning Tree Algorithm (STA) selects the root bridge as a reference point for all calculations.
Port Roles in STP
- The root bridge has all ports in a forwarding state, known as root ports.
- Non-root bridges connected to the root bridge have ports in a forwarding state, known as designated ports.
- Ports connected to designated ports that are not root ports are known as non-designated ports.
- Speed of ports is used to calculate link cost back to the root bridge.
STP Convergence
- STP convergence is the time it takes for the network to set switch ports to their final spanning-tree port roles, eliminating all potential loops.
- Convergence involves three steps: election of the root bridge, calculation of port roles, and propagation of changes to all switches in the network.
Bridge Protocol Data Units (BPDU) Frames
- After a switch boots, it sends out BPDU frames to participate in the election process.
- The root ID identifies the root bridge in a network topology.
- Switches forward their BPDU frames in the election process, and the switch with the lowest root ID becomes the root bridge.
Path Cost and Preference
- The cost of a path in STP can be managed to specify a preferred path.
- Changing the cost of a particular path affects the Spanning Tree Algorithm (STA).
- The command
spanning-tree costsets the cost to a specific value in STP configuration.
Make Your Own Quizzes and Flashcards
Convert your notes into interactive study material.
Get started for free
