Ccna certification Practice Tests

 185.  C.  The default MAC address aging time for dynamic entries is 300 seconds, or 5 minutes. 

All of the other options are incorrect.

 186.  C.  The computer is connected to either another switch or another hub on Gi0/1 since 

there are multiple MAC address entries on Gi0/1. The computer is not likely directly 

connected because of the multiple entries for Gi0/1, unless it was acting as a bridge for 

other computers. The computer cannot be connected to Fa0/1 since an entry is not present 

for the computer. There is no evidence in the exhibit that there is a loop and the MAC 

address table is thrashed.

 187.  B.  When a frame is received on an incoming port, both the incoming port and the source 

MAC address are added to the MAC address table and set with an aging timer. The 

destination MAC address in the incoming frame is used for forward/filter decisions only. 

The destination is never used to populate the table; the aging timer will only be updated 

when a frame is seen on the port and the source address is read. The source MAC address 

and the outgoing port number have no relationship.

 188.  C.  MAC address aging time can be configured via the command 

mac-address-table 

aging-time 400. You can additionally specify a VLAN ID. The command set mac 

aging 400 is incorrect. The command mac aging-time 400 seconds is incorrect. The 

command 

mac address-aging 400 is incorrect.

 189.  A.  Switches make forward/filter decisions based upon the MAC address to port 

association in the MAC address table. Forward/filter decisions are layer 2 switching 

decisions and not layer 3 routing decisions; therefore, the routing table is irrelevant. A 

frame is only flooded to all active ports on a switch under two conditions: the destination 

MAC address is unknown or the MAC address table is full. Broadcasting for the MAC 

address is not a function of switching and, therefore, an incorrect answer.

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