3.1 CCNA 3 - Module 7

1
Which of the following describe the BIDs used in a
spanning tree topology? (Choose two.)
They are sent out by the root bridge only after the
inferior BPDUs are sent.
They consist of a bridge priority and MAC address.
Only the root bridge will send out a BID.
They are used by the switches in a spanning tree
topology to elect the root bridge.
The switch with the fastest processor will have the
lowest BID.

2
Which algorithm is used to create a loop free switched
topology?
Spanning Tree
Shortest Path First
Dykstra
Rapid Tree
Bellman-Ford

3
What is meant by "five nines" network uptime?
A network should be available until 9:00 pm five
days of the week.
A network should be functioning 99.999% of the time.
There should be five nine-port uplinks for each backbone
segment.
Five percent of network expenditures should address
99% of user requirements.
Nothing short of 100% network uptime is acceptable in
modern networks.

4

Switch_A and Switch_B shown in the graphic receive an
ARP request from the host and forward it out their ports.
The switches receive the forwarded requests from each other
and in turn flood the requests again. What will be the result
if this process continues?
a broadcast storm
multicast errors
ARP table errors
MAC address instability
redundant unicast frame forwarding

5
Which of the following are valid STP port states?
(Choose three.)
blocking
learning
converging
listening
switching

6
How often are BPDUs sent by default in a network using
the spanning-tree algorithm?
every second
every two seconds
every three seconds
every four seconds

7
What happens when there is a topology change on a network
that utilizes STP ? (Choose two.)
User traffic is disrupted until recalculation is complete.
The switch recomputes the Spanning Tree topology after
the network converges.
All ports are placed in learning state until convergence
has occurred.
A delay of up to 50 seconds is incurred for convergence of
the new Spanning Tree topology.
User data is forwarded while BPDUs are exchanged to
recompute the topology.

8
How can a network administrator influence which STP switch
becomes the root bridge?
Configure the switch as the static root bridge.
Change the BPDU to a higher value than that of the other
switches in the network.
Change the BPDU to a lower value than that of the other
switches in the network.
Set the switch priority to a smaller value than that of the
other switches in the network.
Set the switch priority to a higher value than that of the
other switches in the network.

9
What features of the Spanning-Tree Protocol contribute to
the time it takes for a switched network to converge after a
topology change occurs? (Choose three.)
the max-age timer
the listening forward delay
the spanning-tree hold down timer
the learning forward delay
the spanning-tree path cost
the blocking delay

10
How does a switch forward a multicast frame through
the network?
It floods it to all ports as a broadcast.
It is forwarded only to ports that contain the
destination address.
It is sent to the port that contains the first
destination address.
It floods it to all ports except the one it was received on.
It is dropped and not sent to any address.

11
Following a link failure, when does Rapid Spanning Tree
Protocol allow point-to-point and edge type links to go to
the forwarding state?
in 15 seconds
never
immediately
in 30 seconds
after 90 seconds

12
What is the first step in the process of convergence in a
spanning tree topology?
election of the root bridge
determination of the designated port for each segment
blocking of the non-designated ports
selection of the designated trunk port
activation of the root port for each segment

13
What link types have been defined for Rapid Spanning-Tree
Protocol? (Choose three.)
shared
end-to-end
edge-type
boundary-type
point-to-many
point-to-point

14
What characteristic of Ethernet makes a redundantly
switched network prone to loops?
Routers are only able to prevent loops at Layer 3,
while Ethernet exists at Layer 2.
The Ethernet protocol has no TTL mechanism.
Switches lack the sophisticated software required to
prevent loops.
Looping of frames is a reliability mechanism built in to
the Ethernet protocol.

15
In which STP state does a switch port transmit user data
and learn MAC addresses?
blocking
learning
disabling
listening
forwarding

16
In which STP state does a port record MAC addresses but
not forward user data?
blocking
learning
disabling
listening
forwarding

17
Which of the following criteria does a switch use to select
the root bridge? (Choose two.)
memory size
bridge priority
switching speed
number of ports
base MAC address
switch location

18
What elements will exist in a converged network with
one spanning tree? (Choose two.)
one root bridge per network
all non-designated ports forwarding
one root port per non-root bridge
multiple designated ports per segment
one designated port per network

19

Refer to the network shown in the graphic. Host1 needs
to transfer data to host2, but host1 has no MAC address
entry in its ARP cache for host2. What will happen on the
network as host1 prepares to transmit its data to host2?
Host1 will receive an ICMP destination unknown message
from switch3.
All hosts in the network shown will receive an ARP
request message from host1.
Multicasting will occur until host2 is located.
Switch3 will send the host2 MAC address from its
bridging table to host1.
A broadcast storm will occur.

20
How much time does it take for a switch port to go from
the blocking state to the forwarding state?
2 seconds
15 seconds
20 seconds
50 seconds

21

Refer to the graphic. Server sends an ARP request for the
MAC address of its default gateway. If STP is not enabled,
what will be the result of this ARP request?
Router_1 will kill the broadcast and reply with the
MAC address of the next hop router.
Switch_A will reply with the MAC address of the
Router_1 E0 interface.
Switch_A and Switch_B will continuously flood the
message onto the network.
Switch_B will broadcast the request and reply with
the Router_1 address.
The message will cycle around the network until its
TTL is exceeded.

22
Which of the following are problems that can occur in
redundantly switched networks? (Choose three.)
broadcast storms
corrupted ARP tables
duplicate MAC addresses
inaccurate routing tables
multiple copies of Ethernet frames
MAC address table instability

23
How is the information contained in BPDUs used by
switches? (Choose two.)
to prevent loops by sharing bridging tables between
connected switches
to set the duplex mode of a redundant link
to determine the shortest path to the root bridge
to determine which ports will forward frames as part
of the spanning tree
to activate looped paths throughout the network

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