6.6 Spanning Tree Protocol

You have just connected four switches as shown in the Exhibit. Assuming the default switch configuration, how can you force switch C to become the root bridge?

Configure a priority number of 4096 for switch C.

A switch running STP is classified as a backup bridge. What state is it in?

Blocking

You have three switches configured as shown in the Exhibit. How can you guarantee that switch C becomes the root bridge?

Configure switch C with a lower priority value.

Which statements accurately describe the port states of both bridges and switches? (Select two.)

For both bridges and switches: In the learning state, ports do not forward frames, but still populate the MAC address table based on frames received. In the blocking state, ports receive BPDUs, but do not forward frames. In the listening state, all ports are blocked.

A switch running STP is in the listening state. A message destined for a different network segment arrives at the switch. Which of the following best describes what the switch will do?

It does not record address or segment information. It does not forward the message.

A switch is running STP is in the learning state. A message destined for a different network segment arrives at the switch. Which of the following best describes what the switch will do?

It uses the source MAC address and network segment information to build its bridge database, but does not forward the message.

Switches running STP are in the process of exchanging BPDUs and redefining their roles. Which port state are the switches currently in?

Listening

You need to configure spanning tree on a Cisco switch. You'd like to use a protocol that conforms to the 802.1w standards. Which protocol should you use?

Rapid PVST+ is the IEEE 802.1w standard. RSTP improves convergence by actively confirming that a switch is ready to transition to a forwarding state, eliminating the listening and learning stages. RSTP defines several new types of links and uses fewer spanning tree states.

Which of the following features dynamically places switch ports in blocking or forwarding states?

Spanning tree

Which of the following solutions would you implement to eliminate switching loops?

Spanning tree

You manage a network that uses multiple switches. You want to provide multiple paths between switches so that if one link goes down, an alternate path is available. Which feature should your switch support?

Spanning tree

You manage a single subnet with three switches. The switches are connected to provide redundant paths between the switches. Which feature prevents switching loops and ensures there is only a single active path between any two switches?

Spanning tree is a protocol on a switch that allows the switch to maintain multiple paths between switches within a subnet. The spanning tree protocol runs on each switch and is used to select a single path between any two switches.

Which problem does the spanning tree protocol prevent?

Switching loops from developing when redundant paths are implemented between switches.

You have just connected four switches as shown in the Exhibit. Assuming the default switch configuration, which switch will become the root bridge?

The switch with the lowest bridge ID becomes the root bridge. The bridge ID is composed of two parts, a bridge priority number and the MAC address assigned to the switch. The default priority number for all switches is 32,768. This means that for unconfigured switches, the switch with the lowest MAC address becomes the root bridge. In this example, bridge B has the lowest MAC address.