Unsure about an answer

tecnodog7

So after studying for almost 2 months I am ready to go for my CCENT Exam.

While doing practice questions I came across this one which I AM sure the answer is wrong. Please someone let me know if this is correct and if I am wrong someone can explain why the answer is that is listed.

SwitchA#show mac-address-table
<non-essential output omitted >

Destination address Address Type vlan destination port

00b0.d056.fe4d Dynamic 1 fa0/3
00b0.d043.ac2e Dynamic 1 fa0/4
00b0.d0fe.ac32 Dynamic 1 fa0/5
00b0.d0da.cb56 Dynamic 1 fa0/6

Frame received by SwitchA
Source MAC DestinationMAC SourceIP DestinationIP
00b0.d056.fe4d 00b0.d0da.cb56 192.168.40.5 192.168.40.6

SwitchA receives the frame with the addressing shown. According to the command output also
shown in the exhibit, how will SwitchA handle this frame?
A. It will drop the frame.
B. It will forward the frame out port Fa0/6 only.
C. It will flood the frame out all ports.
D. It will flood the frame out all ports except Fa0/3.
Answer: D


I say its B since the if you look at the mac-adddress-table you already see the destination MAC address in fa 0/6 so then why would it send it to all the ports?

Thanks in davance

Archon

I would say the answer is: B. It will forward the frame out port Fa0/6 only.

tecnodog7

See that's what I thought to, but the answer was saying D and it was ******* me off!

bharvey92

I would say answer D. MAC table is built from src Mac addresses and not destination Mac addresses. Therefore, the switch would forward thr frame out of all ports except the one received on (fa0/3).

d4nz1g

bharvey92, this switch already had the MAC entry for the destination, so flooding would not be an option.

B FTW

tecnodog7

Thank you guys.
The way I thought about it was, D would be the answer if 00b0.d0da.cb56 Dynamic 1 fa0/6 option wasn't given
But since it is show in there, then this would be a unicast instead of a broadcast like the answer suggested.

Thank you all for taking the time out and answering the question and that makes me feel good that i know my stuff

Switch1

Source MAC is already in CAM table.
Destination MAC is already in CAM table.
Both are in the same VLAN.

The frame will be forwarded directly to the destination as a unicast via fa0/6.

B.

Nothing has you questioning your sanity more than incorrect answers to questions you're aware of.

gorebrush

B, every day.