CNA 251 - Chapter 3
D) Link types are determined automatically.
A network administrator is preparing the implementation of Rapid PVST+ on a production network. How are the Rapid PVST+ link types determined on the switch interfaces? A) Link types must be configured with specific port configuration commands. B) Link types can only be configured on access ports configured with a single VLAN. C) Link types can only be determined if PortFast has been configured. D) Link types are determined automatically.
D) Each switch will analyze the sum of all port costs to reach the root and use the path with the lowest cost.
After the election of the root bridge has been completed, how will switches find the best paths to the root bridge? A) Each switch will analyze the sum of the hops to reach the root and use the path with the fewest hops. B) Each switch will analyze the BID of all neighbors to reach the root and use the path through the lowest BID neighbors. C) Each switch will analyze the port states of all neighbors and use the designated ports to forward traffic to the root. D) Each switch will analyze the sum of all port costs to reach the root and use the path with the lowest cost.
A) show spanning-tree
An administrator is troubleshooting a switch and wants to verify if it is a root bridge. What command can be used to do this? A) show spanning-tree B) show running-config C) show startup-config D) show vlan
B) All the switches send out BPDUs advertising themselves as the root bridge.
During the implementation of Spanning Tree Protocol, all switches are rebooted by the network administrator. What is the first step of the spanning-tree election process? A) Each switch with a lower root ID than its neighbor will not send BPDUs. B) All the switches send out BPDUs advertising themselves as the root bridge. C) Each switch determines the best path to forward traffic. D) Each switch determines what port to block to prevent a loop from occurring.
2
Fill in the blank. Use a number. The default hello timer value for STP BPDU frames is ____ seconds.
B) lowest MAC address
If no bridge priority is configured in PVST, which criteria is considered when electing the root bridge? A) highest MAC address B) lowest MAC address C) lowest IP address D) highest IP address
A) forwarding D) learning
In which two PVST+ port states are MAC addresses learned? (Choose two.) A) forwarding B) blocking C) disabled D) learning E) listening
B) forwarding D) learning
In which two port states does a switch learn MAC addresses and process BPDUs in a PVST network? (Choose two.) A) listening B) forwarding C) disabled D) learning E) blocking
Rapid PVST+ - a Cisco enhancement of RSTP to provide a spanning-tree instance for each VLAN STP - the legacy standard for STP that runs all VLANs in a single spanning-tree instance MSTP - a protocol that allows multiple VLANs to run in a single spanning-tree instance
Match the STP protocol with the correct description. (Not all descriptions are used.) Protocols: Rapid PVST+ STP MSTP Descriptions: -a protocol that allows multiple VLANs to run in a single spanning-tree instance -the legacy standard for STP that runs all VLANs in a single spanning-tree instance -an evolution of STP that provides faster convergence -a Cisco enhancement of RSTP to provide a spanning-tree instance for each VLAN
PVST+ - RSTP - MSTP - MST - Rapid PVST+ - I'm not sure what the correct answer is here, I actually got this correct but the Item Feedback Report doesn't show your correct answers... I may have forgot to fill-in my answers before submitting...
Match the spanning-tree feature with the protocol type. (Not all options are used.) Options: -Proprietary per VLAN implementation of IEEE 802.1w -Cisco implementation of IEEE 802.1D -Fast coverging enhancement of IEEE 802.1D -IEEE standard that reduces the number of STP instances Protocol Type: PVST+ RSTP MSTP MST Rapid PVST+
B) The role of the ports in all VLANs. C) The root bridge BID.
To obtain an overview of the spanning tree status of a switched network, a network engineer issues the show spanning-tree command on a switch. Which two items of information will this command display? (Choose two.) A) The IP address of the management VLAN interface. B) The role of the ports in all VLANs. C) The root bridge BID. D) The status of native VLAN ports. E) The number of broadcasts received on each root port.
C) VLAN ID
What additional information is contained in the 12-bit extended system ID of a BPDU? A) MAC address B) port ID C) VLAN ID D) IP address
B) Broadcast frames are forwarded back to the sending switch.
What is a characteristic of a Layer 2 loop? A) A switch is continually forwarding the same unicast frame. B) Broadcast frames are forwarded back to the sending switch. Routers continually forward packets to other routers. The Time-to-Live attribute of a frame is set to infinity.
D) designing a network to use multiple paths between switches to ensure there is no single point of failure
What is an accurate description of redundancy? A) configuring a router with a complete MAC address database to ensure that all frames can be forwarded to the correct destination B) configuring a switch with proper security to ensure that all traffic forwarded through an interface is filtered C) designing a network to use multiple virtual devices to ensure that all traffic uses the best path through the internetwork D) designing a network to use multiple paths between switches to ensure there is no single point of failure
A) PVST+ optimizes performance on the network through load sharing.
What is an advantage of PVST+? A) PVST+ optimizes performance on the network through load sharing. B) PVST+ requires fewer CPU cycles for all the switches in the network. C) PVST+ reduces bandwidth consumption compared to traditional implementations of STP that use CST. D) PVST+ optimizes performance on the network through autoselection of the root bridge.
D) Manually remove redundant links in the switched network.
What is one way to correct a spanning tree failure? A) Replace all instances of STP with RSTP. B) Insert redundant links to replace the failed STP links. C) Replace the cables on failed STP links. D) Manually remove redundant links in the switched network.
A) New traffic is discarded by the switch because it is unable to be processed.
What is the outcome of a Layer 2 broadcast storm? A) New traffic is discarded by the switch because it is unable to be processed. B) CSMA/CD will cause each host to continue transmitting frames. C) ARP broadcast requests are returned to the transmitting host. D) Routers will take over the forwarding of frames as switches become congested.
A) prevents Layer 2 loops
What is the purpose of the Spanning Tree Protocol (STP)? A) prevents Layer 2 loops creates smaller broadcast domains creates smaller collision domains prevents routing loops on a router allows Cisco devices to exchange routing table updates
A) StackWise
What port type is used to interconnect switches in a switch stack? A) StackWise B) edge C) designated D) root
B) MAC address
What value determines the root bridge when all switches connected by trunk links have default STP configurations? A) VLAN ID B) MAC address C) extended system ID D) bridge priority
B) listening
When PVST is running over a switched network, which port state can participate in BPDU frame forwarding based on BPDUs received, but does not forward data frames? A) blocking B) listening C) forwarding D) disabled
D) BPDU guard
Which Cisco switch feature ensures that configured switch edge ports do not cause Layer 2 loops if a port is mistakenly connected to another switch? A) PVST+ B) extended system ID C) PortFast D) BPDU guard
C) edge ports
Which RSTP ports are connected to end devices? A) designated ports B) root ports C) edge ports D) trunk ports
B) root port
Which STP port role is adopted by a switch port if there is no other port with a lower cost to the root bridge? A) designated port B) root port C) alternate D) disabled port
D) spanning-tree vlan 10 priority 0
Which STP priority configuration would ensure that a switch would always be the root switch? A) spanning-tree vlan 10 root primary B) spanning-tree vlan 10 priority 4096 C) spanning-tree vlan 10 priority 61440 D) spanning-tree vlan 10 priority 0
B) PVST+
Which is the default STP operation mode on Cisco Catalyst switches? A) RSTP B) PVST+ C) MST D) MSTP E) Rapid PVST+
A) forwarding
Which port state will switch ports immediately transition to when configured for PortFast? A) forwarding B) learning C) listening D) blocking
A) MST
Which protocol provides up to 16 instances of RSTP, combines many VLANs with the same physical and logical topology into a common RSTP instance, and provides support for PortFast, BPDU guard, BPDU filter, root guard, and loop guard? A) MST B) PVST+ C) STP D) Rapid PVST+
A) 802.1D
Which spanning tree standard supports only one root bridge so that traffic from all VLANs flows over the same path? A) 802.1D B) PVST+ C) MST D) Rapid PVST
B) extended system ID C) bridge priority E) MAC address
Which three components are combined to form a bridge ID? A) IP address B) extended system ID C) bridge priority D) cost E) MAC address F) port ID
A) discarding E) learning F) forwarding
Which three port states are used by Rapid PVST+? (Choose three.) A) discarding B) blocking C) trunking D) listening E) learning F) forwarding
B) edge port D) PortFast
Which two concepts relate to a switch port that is intended to have only end devices attached and intended never to be used to connect to another switch? (Choose two.) A) bridge ID B) edge port C) extended system ID D) PortFast E) PVST+
B) Due to high processing demands during a broadcast storm, communication may fail between end stations in the broadcast domain. D) During a broadcast storm, constant changes to the MAC address table prevent a switch from accurately forwarding frames.
Which two issues are the result of a broadcast storm? (Choose two.) A) During a broadcast storm, a switch will forward excessive Layer 2 broadcast traffic to the router, and the router will then forward these broadcasts to its attached networks. B) Due to high processing demands during a broadcast storm, communication may fail between end stations in the broadcast domain. C) In a network saturated with broadcast traffic, new traffic arriving at the switch will be forwarded into the broadcast domain, which further consumes available bandwidth. D) During a broadcast storm, constant changes to the MAC address table prevent a switch from accurately forwarding frames. E) During a broadcast storm, switches with high speed interfaces will forward traffic in half-duplex mode to conserve available bandwidth.
D) redundant links between Layer 2 switches E) removing single points of failure with multiple Layer 2 switches
Which two network design features require Spanning Tree Protocol (STP) to ensure correct network operation? (Choose two.) A) link-state dynamic routing that provides redundant routes B) static default routes C) implementing VLANs to contain broadcasts D) redundant links between Layer 2 switches E) removing single points of failure with multiple Layer 2 switches
B) The switch port immediately transitions from blocking to the forwarding state. C) The switch port should never receive BPDUs.
Which two statements describe a switch port that is configured with PortFast? (Choose two.) A) The switch port immediately transitions from the listening to the forwarding state. B) The switch port immediately transitions from blocking to the forwarding state. C) The switch port should never receive BPDUs. D) The switch port immediately processes any BPDUs before transitioning to the forwarding state. E) The switch port sends DHCP requests before transitioning to the forwarding state.
A) STP E) RSTP
Which two types of spanning tree protocols can cause suboptimal traffic flows because they assume only one spanning-tree instance for the entire bridged network? (Choose two.) A) STP B) MSTP C) PVST+ D) Rapid PVST+ E) RSTP
