Modules 5 - 8
root bridge
A switch is configured to run STP. What term describes the reference point for all path calculations? root bridge root port designated port alternate port
root port
A switch is configured to run STP. What term describes the switch port closest, in terms of overall cost, to the root bridge? root port designated port alternate port disabled
It is Cisco proprietary.
Which statement is true regarding the use of PAgP to create EtherChannels? It requires full duplex. It increases the number of ports that are participating in spanning tree. It requires more physical links than LACP does. It mandates that an even number of ports (2, 4, 6, etc.) be used for aggregation. It is Cisco proprietary.
S2
Which switch will be the root bridge after the election process is complete? S1 Bride ID: Priority: 32769 MAC:00A00032222 S2 Bride ID: Priority: 32769 MAC:00A00031111 S3 Bride ID: Priority: 32769 MAC:00A00033333 S4 Bride ID: Priority: 32769 MAC:00A00031212
learning forwarding
In which two PVST+ port states are MAC addresses learned? (Choose two.) learning forwarding disabled listening blocking
desirable auto
Which two channel group modes would place an interface in a negotiating state using PAgP? (Choose two.) on desirable active auto passive
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? Each switch with a lower root ID than its neighbor will not send BPDUs. All the switches send out BPDUs advertising themselves as the root bridge. Each switch determines the best path to forward traffic. Each switch determines what port to block to prevent a loop from occurring.
Traffic cannot be sent to two different switches through the same EtherChannel link.
The administrator tried to create an EtherChannel between S1 and the other two switches via the commands that are shown, but was unsuccessful. Links from S1 S1 - S2 (F0/1 - F0/4) (F0/2 - F0/1) S1 - S3 (Fa0/4 - Fa0/2) (Fa0/3 - Fa0/1) S1 (config)# int range fa0/1 - 4 S1 (config)# channel-group 1 mode on What is the problem? Traffic cannot be sent to two different switches through the same EtherChannel link. Traffic cannot be sent to two different switches, but only to two different devices like an EtherChannel-enabled server and a switch. Traffic can only be sent to two different switches if EtherChannel is implemented on Gigabit Ethernet interfaces. Traffic can only be sent to two different switches if EtherChannel is implemented on Layer 3 switches.
PAgP on on auto desirable desirable desirable LACP on on active active passive active The EtherChannel mode chosen on each side of the EtherChannel must be compatible in order to enable it.
The possible combinations to establish an EtherChannel between two switches using LACP or PAgP are as follows:
Spanning Tree Protocol views the physical links in an EtherChannel as one logical connection. Configuring the EtherChannel interface provides consistency in the configuration of the physical links.
What are two advantages of EtherChannel? (Choose two.) Spanning Tree Protocol views the physical links in an EtherChannel as one logical connection. Load balancing occurs between links configured as different EtherChannels. Configuring the EtherChannel interface provides consistency in the configuration of the physical links. Spanning Tree Protocol ensures redundancy by transitioning failed interfaces in an EtherChannel to a forwarding state. EtherChannel uses upgraded physical links to provide increased bandwidth.
The MAC address table becomes unstable Broadcast frames are transmitted indefinitely
What are two drawbacks to turning spanning tree off and having multiple paths through the Layer 2 switch network? (Choose two.) The MAC address table becomes unstable. The switch acts like a hub. Port security becomes unstable. Broadcast frames are transmitted indefinitely. Port security shuts down all of the ports that have attached devices.
prevents Layer 2 loops
What is the purpose of the Spanning Tree Protocol (STP)? creates smaller collision domains prevents routing loops on a router prevents Layer 2 loops allows Cisco devices to exchange routing table updates creates smaller broadcast domains
the path cost
What is the value used to determine which port on a non-root bridge will become a root port in a STP network? the path cost the highest MAC address of all the ports in the switch the lowest MAC address of all the ports in the switch the VTP revision number
on
When EtherChannel is configured, which mode will force an interface into a port channel without exchanging aggregation protocol packets? active auto on desirable
Designated Root
When the show spanning-tree vlan 33 command is issued on a switch, three ports are shown in the forwarding state. In which two port roles could these interfaces function while in the forwarding state? (Choose two.) alternate designated disabled blocked root
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? designated port root port alternate disabled port
The remaining two interfaces continue to load balance traffic.
A network administrator configured an EtherChannel link with three interfaces between two switches. What is the result if one of the three interfaces is down? The remaining two interfaces continue to load balance traffic. The remaining two interfaces become separate links between the two switches. One interface becomes an active link for data traffic and the other becomes a backup link. The EtherChannel fails.
The EtherChannel will remain functional.
A network administrator has configured an EtherChannel between two switches that are connected via four trunk links. If the physical interface for one of the trunk links changes to a down state, what happens to the EtherChannel? Spanning Tree Protocol will transition the failed physical interface into forwarding mode. Spanning Tree Protocol will recalculate the remaining trunk links. The EtherChannel will transition to a down state. The EtherChannel will remain functional.
SW2(config-if-range)# channel-group 1 mode desirable
A network administrator is configuring an EtherChannel link between switches SW1 and SW2 by using the command SW1(config-if-range)# channel-group 1 mode auto . Which command must be used on SW2 to enable this EtherChannel? SW2(config-if-range)# channel-group 1 mode passive SW2(config-if-range)# channel-group 1 mode desirable SW2(config-if-range)# channel-group 1 mode on SW2(config-if-range)# channel-group 1 mode active
Configure SW2 EtherChannel mode to desirable. The EtherChannel mode must be compatible on each side for the link to work. The three modes from PAgP protocol are on, desirable, and auto. The three modes from LACP protocol are on, active, and passive. The compatible modes include on-on, auto-desirable, desirable-desirable, active-passive, and active-active. Any other combinations will not form an EtherChannel link.
A network administrator is configuring an EtherChannel link between two switches, SW1 and SW2. However, the EtherChannel link fails to establish. What change in configuration would correct the problem? SW1# show running-config channel-group 1 mode auto SW2# show running-config channel-group 1 mode active Configure SW2 EtherChannel mode to desirable. Configure SW2 EtherChannel mode to on. Configure SW1 EtherChannel mode to on. Configure SW2 EtherChannel mode to auto.
The EtherChannel fails to establish. The interfaces GigabitEthernet 0/1 and GigabitEthernet 0/2 are configured "on" for the EtherChannel link. This mode forces the interface to channel without PAgP or LACP. The EtherChannel will be established only if the other side is also set to "on". However, the mode on SW2 side is set to PAgP desirable. Thus the EtherChannel link will not be established.
A network administrator is configuring an EtherChannel link between two switches, SW1 and SW2. Which statement describes the effect after the commands are issued on SW1 and SW2? SW1(config-if)# channel-group 1 mode on SW2(config-if)# channel-group 1 mode desirable The EtherChannel is established after SW2 initiates the link request. The EtherChannel is established after SW1 initiates the link request. The EtherChannel is established without negotiation. The EtherChannel fails to establish.
The EtherChannel is not functional.
A network administrator issued the show etherchannel summary command on the switch S1. #show etherchannel summary Group: 1 Port-channel: Po1 (SD) Protocol: PAgP Ports: Fa0/1(I) Fa0/2(I) Fa0/3(I) What conclusion can be drawn? The EtherChannel is suspended. The EtherChannel is not functional. The port aggregation protocol PAgP is misconfigured. FastEthernet ports Fa0/1, Fa0/2, and Fa0/3 do not join the EtherChannel.
61440
A set of switches is being connected in a LAN topology. Which STP bridge priority value will make it least likely for the switch to be selected as the root? 65535 4096 32768 61440
28672
A small company network has six interconnected Layer 2 switches. Currently all switches are using the default bridge priority value. Which value can be used to configure the bridge priority of one of the switches to ensure that it becomes the root bridge in this design? 1 28672 32768 34816 61440
Bridge priority
A switch is configured to run STP. What term describes a field that has a default value of 32,768 and is the initial deciding factor when electing a root bridge? bridge priority MAC Address extended system ID bridge ID
extend system ID
A switch is configured to run STP. What term describes a field used to specify a VLAN ID? extended system ID port ID bridge priority bridge ID
designated port
A switch is configured to run STP. What term describes a non-root port that is permitted to forward traffic on the network? root port designated port alternate port disabled
The EtherChannel was not configured with the same allowed range of VLANs on each interface.
An EtherChannel was configured between switches S1 and S2, but the interfaces do not form an EtherChannel. What is the problem? he interface port-channel number has to be different on each switch. The switch ports were not configured with speed and duplex mode. The switch ports have to be configured as access ports with each port having a VLAN assigned. The EtherChannel was not configured with the same allowed range of VLANs on each interface.
desirable
An administrator wants to form an EtherChannel between the two switches by using the Port Aggregation Protocol. If switch S1 is configured to be in auto mode, which mode should be configured on S2 to form the EtherChannel? auto on off desirable
Forwarding Learning
In which two port states does a switch learn MAC addresses and process BPDUs in a PVST network? (Choose two.) disabled forwarding listening blocking learning
source IP to destination IP source MAC to destination MAC
What are two load-balancing methods in the EtherChannel technology? (Choose two.) combination of source port and IP to destination port and IP source IP to destination IP source port to destination port combination of source MAC and IP to destination MAC and IP source MAC to destination MAC
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 Rapid PVST+ A Cisco enhancement of RSTP to provide a spanning-tree instance for each VLAN
Match the STP protocol with the correct description. (Not all options are used.) Rapid PVST+ STP MSTP The legacy standard for STP that runs all VLANs in a single spanning-tree instance A protocol that allows multiple VLANs to run in a single spanning-tree instance A Cisco enhancement of RSTP to provide a spanning-tree instance for each VLAN An evolution of STP that provides faster convergence
Rapid PVST+ Proprietary per VLAN implementation of IEEE 802.1w PVST+ Cisco implementation of IEEE 802.1D RSTP Fast converging enhancement of IEEE 802.1D MSTP IEEE standard that reduces the number of STP instances
Match the spanning-tree feature with the protocol type. (Not all options are used.) Proprietary per VLAN implementation of IEEE 802.1w Cisco implementation of IEEE 802.1D Fast converging enhancement of IEEE 802.1D IEEE standard that reduces the number of STP instances PVST+ RSTP MSTP MST Rapid PVST+
A Cisco proprietary protocol was used to negotiate the EtherChannel link.
On the basis of the output that is shown, what can be determined about the EtherChannel bundle? #show etherchannel summary Group: 1 Port-Channel: Po1(SU) Protocol: PAgP Ports: Fa0/1(P) Fa0/2(P) The EtherChannel bundle is down. Two Gigabit Ethernet ports are used to form the EtherChannel. A Cisco proprietary protocol was used to negotiate the EtherChannel link. The EtherChannel bundle is operating at both Layer 2 and Layer 3.
VLAN ID
What additional information is contained in the 12-bit extended system ID of a BPDU? MAC address VLAN ID IP address port ID
alternate, designated, root, root
What are the possible port roles for ports A, B, C, and D in this RSTP-enabled network? alternate, designated, root, root designated, alternate, root, root alternate, root, designated, root designated, root, alternate, root
It allows directly connected switches to negotiate an EtherChannel link. It allows the use of multivendor devices.
What are two advantages of using LACP? (Choose two.) It allows directly connected switches to negotiate an EtherChannel link. It eliminates the need for configuring trunk interfaces when deploying VLANs on multiple switches. It decreases the amount of configuration that is needed on a switch. It provides a simulated environment for testing link aggregation. It allows the use of multivendor devices. LACP allows Fast Ethernet and Gigabit Ethernet interfaces to be mixed within a single EtherChannel.
All the interfaces need to work at the same speed. All the interfaces need to be working in the same duplex mode.
What are two requirements to be able to configure an EtherChannel between two switches? (Choose two.) All the interfaces need to work at the same speed. All interfaces need to be assigned to different VLANs. Different allowed ranges of VLANs must exist on each end. All the interfaces need to be working in the same duplex mode. The interfaces that are involved need to be contiguous on the switch.
It is enabled by default on Cisco switches.
What is a characteristic of spanning tree? It is enabled by default on Cisco switches. It is used to discover information about an adjacent Cisco device. It has a TTL mechanism that works at Layer 2. It prevents propagation of Layer 2 broadcast frames.
The allowed range of VLANs must be the same on both switches.
What is a requirement to configure a trunking EtherChannel between two switches? The allowed range of VLANs must be the same on both switches. The participating interfaces must be assigned the same VLAN number on both switches. The participating interfaces must be physically contiguous on a switch. The participating interfaces must be on the same module on a switch.
It disables redundant paths to eliminate Layer 2 loops.
What is the function of STP in a scalable network? It decreases the size of the failure domain to contain the impact of failures. It protects the edge of the enterprise network from malicious activity. It combines multiple switch trunk links to act as one logical link for increased bandwidth. It disables redundant paths to eliminate Layer 2 loops.
New traffic is discarded by the switch because it is unable to be processed.
What is the outcome of a Layer 2 broadcast storm? Routers will take over the forwarding of frames as switches become congested. New traffic is discarded by the switch because it is unable to be processed. CSMA/CD will cause each host to continue transmitting frames. ARP broadcast requests are returned to the transmitting host.
SW1: on SW2: on
Which mode configuration setting would allow formation of an EtherChannel link between switches SW1 and SW2 without sending negotiation traffic? SW1: on SW2: on SW1: desirable SW2: desirable SW1: auto SW2: auto trunking enabled on both switches SW1: auto SW2: auto PortFast enabled on both switches SW1: passive SW2: active
root port
Which port role is assigned to the switch port that has the lowest cost to reach the root bridge? designated port disabled port root port non-designated port
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? STP Rapid PVST+ PVST+ MST
interface GigabitEthernet0/1 channel-group 1 mode desirable show running-configuration command on SW1 shows that interface GigabitEthernet0/1 is missing the channel-group 1 mode desirable command which will compete the EtherChannel configuration for interface GigabitEthernet0/1 and interface GigabitEthernet0/2
Which set of configuration commands issued on SW1 will successfully complete the EtherChannel link between SW1 and SW2? G0/1 on SW1 is connected to G0/1 on SW2. G0/2 on SW1 is connected to G0/2 on SW2. EtherChannel is correctly configured on SW2 G0/1 and G0/2. Access SW1 from PC1 and examine SW1 configuration. Choose one: Interface GigabitEthernet0/1 no shutdown interface Port-channel 1 no shutdown interface GigabitEthernet0/2 channel-group 2 mode desirable interface GigabitEthernet0/1 channel-group 1 mode desirable
802.1D
Which spanning tree standard supports only one root bridge so that traffic from all VLANs flows over the same path? PVST+ 802.1D MST Rapid PVST
It is made by combining multiple physical links that are seen as one link between two switches.
Which statement describes a characteristic of EtherChannel? It can combine up to a maximum of 4 physical links. It can bundle mixed types of 100 Mb/s and 1Gb/s Ethernet links. It consists of multiple parallel links between a switch and a router. It is made by combining multiple physical links that are seen as one link between two switches.
A trunked port can be part of an EtherChannel bundle.
Which statement describes an EtherChannel implementation? EtherChannel operates only at Layer 2. PAgP cannot be used in conjunction with EtherChannel. A trunked port can be part of an EtherChannel bundle. EtherChannel can support up to a maximum of ten separate links.
EtherChannel
Which switching technology would allow each access layer switch link to be aggregated to provide more bandwidth between each Layer 2 switch and the Layer 3 switch? trunking HSRP PortFast EtherChannel
LACP (Link Aggregation Control Protocol)
Which technology is an open protocol standard that allows switches to automatically bundle physical ports into a single logical link? PAgP LACP Multilink PPP DTP
Extended system Bridge priority MAC address
Which three components are combined to form a bridge ID? extended system ID cost IP address bridge priority MAC address port ID
Edge port 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.) bridge ID edge port extended system ID PortFast PVST
redundant links between Layer 2 switches 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.) static default routes implementing VLANs to contain broadcasts redundant links between Layer 2 switches link-state dynamic routing that provides redundant routes removing single points of failure with multiple Layer 2 switches
speed VLAN information
Which two parameters must match on the ports of two switches to create a PAgP EtherChannel between the switches? (Choose two.) port ID PAgP mode MAC address speed VLAN information
