Ccna certification Practice Tests

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 71.  B.  When you configure the switch port to a mode of access, you are statically 

configuring the interface to remain an access switch port. When you configure the 

switch port to nonegotiate, you are turning off Dynamic Trunking Protocol (DTP). 

The switch will never negotiate its switch port. If the interface mode is specifically set 

with the command 

switchport mode access, it will never become a trunk. Regardless 

of what is plugged into the interface, the command 

switchport mode access will 

configure it as an access port.

 72.  B.  The command to specify 802.1Q encapsulation on a trunk interface is 

switchport 

trunk encapsulation 802.1q. The command switchport mode trunk 802.1q is 

incorrect. The command 

switchport 802.1q is incorrect. The command switchport 

encapsulation trunk 802.1q is incorrect.

 73.  D.  This error is very common when configuring Cisco switches since many switches only 

support 802.1Q and configuration is not necessary. The ISL trunking protocol is not 

supported on certain platforms, such as the older 2900 series switches. It is safe to assume 

that Cisco switches at minimum will support 802.1Q encapsulation, but ISL trunking 

protocol is usually a feature that must be added or purchased.

 74.  C.  When a frame traverses a trunk and does not have VLAN tagging information in 

the 802.1Q encapsulation format (untagged), it is sent to the native VLAN configured 

on the trunk. This behavior is to prevent the untagged frame from being dropped. The 

terminology of default VLAN does not pertain to trunks. The default VLAN is the default 

VLAN configured on an access port. An untagged frame is only sent to the native VLAN 

and not the first VLAN ID configured on the trunk.

 75.  C.  The 802.1Q protocol is supported by all switches’ vendors for trunking. It is an open 

standard that was developed by the IEEE. Cisco Inter-Switch Link (ISL) is a proprietary 

protocol for trunking. VLAN Trunk Protocol (VTP) helps reduce configuration and 

maintenance of VLANs on Cisco switches. 802.1X is a security protocol used per port to 

allow and deny traffic based on credentials.

 76.  C.  When implementing router on a stick (ROAS), you must first create a trunk to the 

router. Once the trunk is created, you must create subinterfaces for each VLAN to be 

routed and specify the IP address and 802.1Q encapsulation. A virtual interface is an 

interface that is configured inside of the IOS software and does not have a physical 

presence, such as a loopback interface. A switched virtual interface is a type of virtual 

interface inside of the IOS that allows for configuration of the traffic in the respective 

VLAN. The VLAN database is only kept on the switches and the router does not receive  

a copy.

 77.  B.  An 802.1Q frame is a modified Ethernet frame. The type field is relocated after the  

4 bytes used for 802.1Q tagging. Two of the bytes are used for tagging the frame, and two 

of the bytes are used for controls such as Class of Service (CoS). All of the other options 

are incorrect.

 78.  A.  The default VLAN for all switches is VLAN 1. It is the default configuration for all 

access ports from the factory. A native VLAN is the VLAN that untagged frames are 

switched onto if the frames are received on a trunk. A default VLAN is not configured on 

all trunks for tagged frames. A native VLAN is not configured on all trunks for tagged 

frames.

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