Which command entered on a switch configured with Rapid PVST+ listens and learns for a specific time period?
Which command entered on a switch configured with Rapid PVST+ listens and learns for a specific time period?
The correct command is 'switch(config)#spanning-tree vlan 1 forward-time 20'. In Rapid PVST+, the forward delay timer controls the time a port spends in the listening and learning states before transitioning to the forwarding state. This allows the switch to 'listen' and 'learn' the network topology for a specific period, ensuring that there is no loop before forwarding packets.
Strange question... In Rapid-PVST+, there's no listening state anymore
It says the forward delay timer has a listening and learning state here: https://www.cisco.com/c/en/us/td/docs/switches/datacenter/nexus3000/sw/layer2/503_U1_1/Cisco_n3k_layer2_config_gd_503_U1_1_chapter7.html#con_1205111
Thank you, was getting confused already.
I belive it is used for backward compatibility to a old switch that only uses STP
correct answer d: yes, you can configure forward delay timer for rapid pvst+. https://www.cisco.com/c/en/us/td/docs/switches/datacenter/nexus5000/sw/layer2/503_n1_1/Cisco_n5k_layer2_config_gd_rel_503_N1_1_chapter9.html#task_1197376
Answer D explanation, it is a backup configuration but it still valid... "Determines how long each of the listening and learning states last before the port begins forwarding. This timer is generally not used by the protocol but is used as a backup. The default is 15 seconds, and the range is from 4 to 30 seconds."
The answer is D, folks. To quote the Official Certification Guide Volume 1 Page 612: Max Age -> "How long any switch should wait, after ceasing to hear Hellos, before trying to change the STP topology. Forward Delay -> "Delay that affects the process that occurs when an interface changes from blocking state to forwarding state. A port stays in an interim listening state, and then an interim learning state, for the number of seconds defined by the forward delay timer." Now, looking at official Cisco docs, we can see the command to change the forward delay time is indeed "forward-time". https://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst4500/12-2/15-02SG/configuration/guide/config/spantree.html#56177
C. switch(config)#spanning-tree vlan 1 max-age 6 Explanation: The max-age parameter controls the maximum age of STP messages in the network, which is the maximum amount of time that a switch will retain information about the network topology before discarding it. By default, the max-age is set to 20 seconds. However, in Rapid PVST+, the max-age can be set as low as 6 seconds to allow for faster convergence. Option A sets the priority of the switch for a specific VLAN. This does not affect the listen and learn time period. Option B sets the hello time for STP messages in the network. This does not affect the listen and learn time period. Option D sets the forwarding delay time for STP. This does not affect the listen and learn time period.
The max-age parameter controls the maximum age of STP messages in the network, which is the maximum amount of time that a switch will retain information about the network topology before discarding it. By default, the max-age is set to 20 seconds. However, in Rapid PVST+, the max-age can be set as low as 6 seconds to allow for faster convergence.
D is correct
https://www.cisco.com/c/en/us/td/docs/switches/datacenter/nexus5000/sw/layer2/503_n1_1/Cisco_n5k_layer2_config_gd_rel_503_N1_1_chapter9.html#task_1197376
D seems correct
The maximum age timer controls the maximum time that a switch port will wait for a BPDU (Bridge Protocol Data Unit) from the root bridge before declaring the current root bridge as lost and initiating a new election process. Option A (Wrong) configures the priority of the switch for a specific VLAN. Option B (Wrong) configures the hello time for STP messages in the network. Option D (Wrong) configures the forwarding delay time for STP.
Gather here and explain to me why D and not C
I now understand. The command "spanning-tree vlan 1 max-age 6" is used to configure the maximum age timer for the Spanning Tree Protocol (STP) on VLAN 1. The "max-age" timer controls the maximum time that a switch port will wait for a BPDU (Bridge Protocol Data Unit) from the root bridge before declaring the current root bridge as lost and initiating a new election process.
Confirm write answer D. Search "Rapid PVST+ Protocol Timers" in following link: https://www.cisco.com/c/en/us/td/docs/switches/datacenter/nexus5000/sw/layer2/503_n1_1/Cisco_n5k_layer2_config_gd_rel_503_N1_1_chapter9.html Regards,
Forward time : Determines how long each of the listening and learning states last before the port begins forwarding. Switch(config)# [ no ] spanning-tree vlan vlan_ID forward-time forward_time Configures the forward time of a VLAN. The forward_time value can be from 4 to 30 seconds. https://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst4500/12-2/15-02SG/configuration/guide/config/spantree.html#56177