Exam 200-301 topic 1 question 178 discussion

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

The primary effect of the spanning-tree portfast command is to skip the STP listening and learning states and immediately transition the port to the forwarding state, which allows for faster network access for end devices (computers, printers, etc.). This is crucial for reducing the time devices need to communicate on the network when plugged in, but it should only be used on end-device ports, not on switch-to-switch links.

B includes a trick, the switch doesn't need to be reloaded.

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.

it´s D

D is more appropriate answer

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

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

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.

D is correct

No need to reload the switch once you set port Fast the port will forward immediately.

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.

D is the correct answer. B is slightly correct however a switch does not need to be reloaded for it to work.

D is the best answer however, really unfair set of choices

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.

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