What is the primary effect of the spanning-tree portfast command?
What is the primary effect of the spanning-tree portfast command?
The primary effect of the spanning-tree portfast command is that it immediately puts the port into the forwarding state. This allows the port to bypass the standard Spanning Tree Protocol (STP) states of listening and learning, providing instant network connectivity for devices connected to that port without waiting for these STP states to complete. This helps prevent delays for end-user devices when they are powered on or connected. Although minimizing spanning-tree convergence time is an indirect benefit, the immediate transition to the forwarding state is the direct primary effect.
I believe D is the right answer. When you enable PortFast on the switch, spanning tree places ports in the forwarding state immediately, instead of going through the listening, learning, and forwarding states. If answer B did not say " when the switch is reloaded" then it would have been the correct answer.
guys, note, the question asks, what is the "primary" effect. Which would be D
Agreed: Because the purpose of Port Fast is to minimize the time interfaces must wait for spanning-tree to converge, it is effective only when used on interfaces connected to end stations.
as long as Portfast is used for ports connected to end stations, then there is no point to ask about the effects of spanning-tree procces, i think its a tricky qusetion
The portfast command does not put the port into the forwarding state when the switch is reloaded. The portfast command takes effect immediately after it is configured on a port, regardless of whether the switch is reloaded or not.
The "spanning-tree portfast" command is used to configure a port as an edge port, typically for end-user devices like computers or IP phones. When this command is applied to a port, it bypasses the normal Spanning Tree Protocol (STP) listening and learning states and immediately transitions the port to the forwarding state as soon as it's activated or the switch is reloaded. This helps to minimize the time it takes for devices to gain network connectivity after they are powered on or connected to the network. The primary effect of the "spanning-tree portfast" command is to quickly enable the port and put it into the forwarding state to allow network traffic to flow without the delay introduced by the STP convergence process. (D) While portfast can contribute to minimizing spanning-tree convergence time by immediately transitioning ports, the primary effect is not about overall convergence time.
The "spanning-tree portfast" command is used to configure a port as an edge port, typically for devices that do not participate in Spanning Tree Protocol (STP) such as end-user devices like computers or IP phones.
D is more appropriate answer
The spanning-tree portfast command immediately puts the port into the forwarding state when the switch is reloaded. So the answer is B. The listening and learning states are bypassed when the spanning-tree portfast command is used. This minimizes the spanning-tree convergence time, which is the time it takes for a switch to detect a topology change and converge to a new spanning-tree topology. BPDU messages are used by the Spanning Tree Protocol (STP) to communicate between switches. The spanning-tree portfast command does not affect BPDU messages. Therefore, the primary effect of the spanning-tree portfast command is to minimize spanning-tree convergence time by immediately putting the port into the forwarding state.
PortFast is a feature can be used to speed up convergence on ports which are connected to a workstation on a server( which will not cause layer 2 loops) # enable #configure terminal #interface fa0/1 -15 #switchport mode access #spanning-tree portfast #exit TO CHECK SPANNING TREE PORTFAST enabled ports Sw#show running-config
D is the best answer however, really unfair set of choices
D is correct
https://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst2960l/software/15-2_5_e/config-guide/b_1525e_consolidated_2960l_cg/b_1525e_consolidated_2960l_cg_chapter_010001.pdf?dtid=osscdc000283
It asks for effect...
Sound like B is also an answer Port Fast immediately brings an interface configured as an access or trunk port to the forwarding state from a blocking state, bypassing the listening and learning states. You can use Port Fast on interfaces connected to a single workstation or server, as shown in Figure 18-1, to allow those devices to immediately connect to the network, rather than waiting for the spanning tree to converge. Interfaces connected to a single workstation or server should not receive bridge protocol data units (BPDUs). An interface with Port Fast enabled goes through the normal cycle of spanning-tree status changes when the switch is restarted.
D is the correct answer. B is slightly correct however a switch does not need to be reloaded for it to work.
No need to reload the switch once you set port Fast the port will forward immediately.
netacad Because the purpose of PortFast is to minimize the time that access ports must wait for spanning tree to converge, slide 5.4.3 semester 2
it´s D
primary effect is the keyword
Cisco developed three proprietary features that improve STP convergence time: PortFast UplinkFast BackboneFast PortFast provides an additional benefit. Remember that a switch will generate a TCN if a port transitions to a forwarding or blocked state. This is true even if the port connects to a host device, such as a workstation. Thus, powering on or off a workstation will cause TCNs to reach the Root Bridge, which will send out configuration BPDUs in response. Because the switching topology did not technically change, no outage will occur. However, all switches will reduce the CAM aging timer to 15 seconds, thus purging MAC addresses from the table very quickly. This will increase frame flooding and reduce the efficiency and performance. PortFast eliminates this unnecessary BPDU traffic and frame flooding. A TCN will not be generated for state changes on a PortFast-enabled port. Therefore D is right and B is discarded because of the reload argument.