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Appendix
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Answers to Practice Test Questions
63. A. You must first set the encapsulation to 802.1Q, then you can statically set the mode
to trunk. An alternative would be to set the port to dynamic desirable via the command
switchport mode dynamic desirable. However, it is recommended to statically
configure the link to trunk on one or both sides if possible. Configuring both sides with
switchport mode dynamic auto will result in the negotiation of an access link. Turning
DTP off by using the command
switchport nonegotiate will result in an access link.
The correct command to set encapsulation is
switchport trunk encapsulation dot1q,
not
switchport encapsulation dot1q.
64. C. Native VLANs are only used for traffic that is not tagged, in which untagged frames
are placed on a trunk link. A common use for native VLANs is management traffic
between switches, before both sides are configured as a trunk. Traffic that is tagged will
traverse the trunk link and not use the native VLAN. Native VLANs are not used for
disallowed VLANs on a trunk link. Any traffic that is tagged with ISL on an 802.1Q
trunk will not be distinguishable on either side since the frame will be mismatched.
65. D. The switch is set up with a VTP mode of transparent. When a switch is set up with a
mode of transparent, the VLAN information is stored in the running-config in lieu of the
vlan.dat file. This is not the default mode of a switch;, out of the box it is configured
as a VTP server. The switch is not set up as a VTP client or server since the VLAN
configuration is visible in the running-config.
66. B. If you issue the command
switchport nonegotiate, the switch will not send
Dynamic Trunking Protocol (DTP) frames for trunk negotiation. The default
configuration for a port is the mode of access, so the port will remain an access port. This
means the switch port will not transition to a trunk port, and it will remain an access
port. The interface will not shut down, but it will be mismatched and not carry any tagged
VLANs. The switch port will not enter an err-disable state.
67. A. Switch A must change its interface to an access port with the
switchport mode
access command, which will force Switch A’s interface to remain an access port. Then
you configure the access VLAN of 5 on Switch A with the
switchport access vlan 5
command. Configuring the port with the mode of a trunk on either switch will prevent the
port from performing as an access port for VLAN 5. If you tried to configure this with a
native VLAN, it would result in a native VLAN mismatch and improper configuration.
68. D. The command
switchport mode dynamic desirable is similar to switchport
mode dynamic auto with the exception that it is desirable to become a trunk. So if the
neighboring port is set to auto, desirable, or trunk, it becomes a trunk.
69. A. The command
switchport mode dynamic auto will cause the port to remain an
access port if the neighboring port is configured the same. If both sides are configured
with
switchport mode dynamic auto, then the port will become an access link. If you
configure the neighboring port as a trunk, it will become a trunk. If the native VLAN is
changed, it will have no effect over the selection of switch port mode.
70. C. The command
show interfaces switchport will show greater detail about the
trunk than the command
show interfaces trunk. Alternatively, you can specify a
single port using the command
show interfaces Fa 0/5 switchport, for example.
The command
show interfaces trunk detail is not similar. The command show
switchport is not similar. The command show running-config is not similar.
Chapter 2: Network Access (Domain 2)
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