Chapter 4 – Spanning Tree Protocol – Flashcards

Refer to the exhibit. What conclusion does the output support? PortFast is enabled on interface Fa0/6. Standard IEEE 802.1D behavior is shown. IEEE 802.1w is enabled on VLAN 1. The forward delay timer has been changed from the default value.

Refer to the exhibit. Switch SW1 is receiving traffic from SW2. However, SW2 is not receiving traffic from SW1. Which STP feature should be implemented to prevent inadvertent loops in the network? BPDU filtering PortFast BPDU guard UDLD

Which two statements are true about STP root guard? - Root guard is enabled on a per-port basis. - Root guard requires that PortFast be enabled on a switch port. - Root guard re-enables a switch port once it stops receiving superior BPDUs. - Root guard should be configured on all ports on the desired root bridge to prevent another bridge from becoming the root. - If a root guard enabled port receives a inferior BPDU from a nonroot switch, the port transitions to the blocking state to prevent a root bridge election.

One switch in a Layer 2 switched spanning-tree domain is converted to PVRST+ using the spanning-tree mode rapid-pvst global configuration mode command. The remaining switches are running PVST+. What is the effect on the spanning-tree operation? Spanning tree is effectively disabled in the network. All switches default to one 802.1D spanning tree for all VLANs. The PVSRT+ reverts to PVST+ to interoperate with the PVST+ switches. The PVRST+ switch forwards 802.1D BPDUs, but does not participate as a node in any spanning tree.

Which protocol extends the IEEE 802.1w Rapid Spanning Tree (RST) algorithm to multiple spanning trees? STP MST CST RSTP+

Which two statements are true about the RSTP negotiations between switches? - UplinkFast must be configured on all designated switches. - BackboneFast must be configured on all root switches. - Switches must be connected by a point-to-point link. - All ports that are directly connected to end stations must be enabled as designated ports. - It greatly improves the restoration times for any VLAN that requires a topology convergence due to link up.

Which protocol should an administrator recommend to manage bridged links when the customer requires a fully redundant network that can utilize load balancing technologies and re-converge on link failures in less than a second? Cisco PVST+ IEEE 802.1s (MST) IEEE 802.1D(STP) IEEE 802.1Q (CST)

What three fields are included in a BPDU? (Choose three.) cost of path link-state ID STP ID port ID bridge ID

Which statement is true about the Spanning Tree Protocol (STP)? With each network change, the STP algorithm is run on all switches that have a root port. The designated port will be on the switch with the best path to the root switch. Each switch determines a designated port that provides the best path to the root switch. A topology change will cause the switch where the change occurred to send messages about the change throughout the tree.

What happens when a switch running IEEE 802.1D receives a topology change message from the root bridge? The switch uses the hello to age out entries in the MAC address table. The switch uses the forward delay and the max-age timer to age out entries in the MAC address table. The switch uses the max-age timer to age out entries in the MAC address table. The switch uses the forward delay timer to age out entries in the MAC address table.

What effect does the global configuration command spanning-tree portfast bpdufilter default have when enabled on an access switch? All switch ports start filtering the superior BPDUs coming from other switches and the access switch becomes a root bridge. All PortFast enabled ports become designated ports. All PortFast enabled ports start participating in the spanning-tree calculations. All PortFast enabled ports stop sending BPDUs, but if a BPDU is received on the port, the port gets out of the PortFast state, thereby disabling the BPDU filtering.

What will happen when a BPDU is received on a loop guard port that is in a loop-inconsistent state? The port will transition to blocking state. The port will be disabled and the administrator must re-enable it manually. The port will transition to forwarding state automatically. The port will transition to the appropriate state as determined by the normal function of the spanning tree.

Refer to the exhibit. What implementation of spanning tree best describes the spanning-tree operational mode of the switch? IEEE 802.1D IEEE 802.1s PVRST+ IEEE 802.w

Assuming that all switches in a network have the default bridge priority for each MST instance, what effect does the command spanning-tree mst 10 root primary have when entered on a single switch? sets the bridge priority on the switch to 24582 for MST instance 10 sets the bridge priority on the switch to 24586 for MST instance 10 sets the bridge priority on the switch to 28672 for MST instance 10 sets the bridge priority on the switch to 24576 for MST instance 10

Which three parameters should match all switches within an MST region? (Choose three.) configuration name VLAN-to-instance mappings port costs on trunk ports bridge priority trunk encapsulation method revision number

Which interfaces should loop guard be enabled on? root port and alternate ports root port and ports configured with PortFast designated ports ports configured with PortFast root ports

Which STP timer defines the length of time spent in the listening and learning states? max age hello time forward aging max delay forward delay

Users complain that they lost connectivity to all resources in the network. A network administrator suspects the presence of a bridging loop as a root cause of the problem. Which two actions will determine the existence of the bridging loop? (Choose two.) Ensure that the root guard and loop guard are properly configured on all distribution links. Confirm MAC port security is enabled on all access switches. Capture the traffic on the saturated link and verify if duplicate packets are seen. Check the port utilization on devices and look for abnormal values. Verify that the management VLAN is properly configured on all root bridges.

What are three important steps in troubleshooting STP problems? (Choose three.) Capture traffic on a saturated link and check whether identical frames are traversing multiple links. Administratively disable multicasting and check to see if connectivity is restored. Administratively disable ports that should be blocking and check to see if connectivity is restored. Administratively create bridge loops and see what path the traffic takes. Adjust BPDU timers so that there is less overhead traffic on the switching fabric. Check each side of a point-to-point link for duplex mismatch.

Refer to the exhibit. After the sequence of commands is entered, how many VLANs will be assigned to the default instance? 4062 4094 4061 4064