Ccna certification Practice Tests

 109.  A.  PAgP sends control notifications every 30 seconds to the adjacent switch. All of the 

other options are incorrect.

 110.  A.  Using active mode on both sides assures us that the switches will start negotiation with 

only Link Aggregation Control Protocol (LACP). A configuration of passive mode on both 

sides will not form an LACP aggregation. Auto and desirable mode only pertain to PAgP.

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Chapter 2: Network Access (Domain 2) 

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 111.  C.  When you use passive on one side and active on the other side of a port channel, the 

result is that Link Aggregation Control Protocol (LACP) will be used. Passive and active 

are synonymous with LACP configuration; therefore, PAgP is not configured with this 

terminology. EtherChannel is a Cisco term related to PAgP.

 112.  A.  The command 

show etherchannel will display all EtherChannels on the switch along 

with their negotiated protocols. The command 

show port-channel is incorrect. The 

command 

show interface is incorrect; it will show interface statistics. The command 

show run is incorrect; it will show the running configuration.

 113.  B.  Since both interfaces are set to passive mode, neither side will initiate the LACP 

control notifications. Although the port channel is configured on the switch, it is not 

communicated between the switches. Passive and active are synonymous with LACP 

configuration; therefore, PAgP is not configured with this terminology. A port channel 

will not be unconditionally formed because both sides are set to passive and will not 

communicate with LACP.

 114.  D.  When both sides of the port channel are configured with the on mode, an 

unconditional port channel is created. This means there is no control protocol assisting the 

port channel. The on mode is configured when you do not want to use a control protocol; 

therefore, PAgP and LACP will not be used.

 115.  C.  The original version of STP was created by Digital Equipment Corporation (DEC). The 

IEEE ratified the specification of STP as 802.1D in 1990. 802.1X is the IEEE standard for 

port security that requires end devices authenticate before traffic will be allowed to pass. 

802.1w is the IEEE standard for Rapid Spanning Tree Protocol (RSTP). 802.1s is the IEEE 

standard for Multiple Spanning Tree Protocol (MST).

 116.  B.  Spanning Tree Protocol runs as a distributed process on each switch. Each switch 

creates and maintains its own topology database referencing and electing the root bridge. 

STP does not use routing protocols because it is a layer 2 protocol. STP uses Bridge  

frames to check for switching loops.

 117.  A.  STP monitors all interfaces for BPDUs, which carry switches’ identities. When it sees 

the same switch ID in BPDUs on multiple interfaces, a redundant link is detected. STP will 

not listen to normal traffic frames or CDP on multiple interfaces. The STP protocol is only 

concerned with BPDUs since they are only generated by switches that can cause loops. 

STP can run independently on several different VLANs.

 118.  B.  The original STP specification was revamped in 2004 with RSTP 802.1w. This 

revamping of STP was to fix problems with the original specification. 802.1X is the IEEE 

standard for port security that requires end devices to authenticate before traffic will be 

allowed to pass. 802.1s is the IEEE standard for Multiple Spanning Tree Protocol (MST). 

The original version of STP is the 802.1D IEEE specification.

 119.  D.  The link cost is a numeric value that represents the cost in speed of a link. The higher 

the numbers, the lower the speed of the link, thus a higher cost. The link cost is not related 

to the latency of the frame traversing the link. The link cost is not a calculation of all the 

ports in the path to the root bridge; this is considered the path cost, not the link cost. There 

is also no monetary cost associated with a link because it pertains to STP link cost.

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