CCNA question what's the answer

[HodgeHi]

Hello,

 

I am looking through a demo course for a CISCO CCNA online course.

 

I have come across a question where i think i have the right answer but yet it does not seem to accept it. I may be wrong but i don't think it is

 

So what do you guys think?

[ICTNUT]

What do you think the correct answer is??

[HodgeHi]

None ticked for switch to forward the frame and the frame is unicast but dropped as the port number for the destination is the same as the source which is what the switch should do according to the help section.

 

Am i right?

 

Here's what the help says...

Edited July 14, 2008 by HodgeHi
adding the help screenshot

[Technomancer]

Given that the diagram has the MAC address for 0B entered in the table I'd suggest a typo in the question. Frankly not that unusual with Cisco materials.

[Geoff]

Answer to part 1:

 

The destination MAC address is '0E'. According to the MAC table '0E' lives at port Fa9. Therefore the switch will forward the frame to port Fa9.

 

Answer to part 2:

 

A is false. The switch already has the source MAC address recorded in it's MAC table correctly.

B is false. The frame is not a broadcast frame.

C is true. This is the normal operating behaviour for a switch dealing with unicast frames once it's located the destination mac address/port pair.

D is false. As far as we've been told, the switch hasn't exceeded it's memory/cpu capacity. This is the only situation, aside from misconfiguration, when such a thing would occur.

E is false. The switch knows where the destination is and has not been instructed to drop frames to the destination port/mac as far as we've been told.

[ICTNUT]

I agree with Geoff.

[HodgeHi]

I will let you know if you are correct as i have continued on. Give me about ten minutes and i should be able to post up if it was accepted.

[HodgeHi]

Ok i put in Fa9 and C.

 

drum roll....

 

Fa9 was rejected as being the wrong answer.

 

If i do not choose any for Q1 it says that Q2 answer C is incorrect.

Edited July 14, 2008 by HodgeHi

[ConTheITGuy]

Surely 0E has already received the data, being connected to the same hub as 0F. Would the switch forward the data to the port where it had received from? Or would it realise that the destination should already have received, and so drop it?

 

Hmmm...

[HodgeHi]

If the switch resends the data back to the host that is supposed receive the data then the host will receive it twice. This is, i assume, why the switch drops the frame when coming from the same port as destination.

[webman]

Don't tick anything for question 1.

[HodgeHi]

@webman

 

I haven't ticked anything for Q1 but Q2 is still wrong. I think i have tried nearly every single combination available (probably apart from the right one).

[webman]

The last option for Question 2.

[HodgeHi]

I also chose the last one. It never tells me that it is correct. I think there is a problem with this question. I have emailed it to the course tutor.

 

Thanks for all your responses. Keep 'em coming

[torledo]

I think there is something wrong with the answer options....

 

the switch should not be forwarding the frame at all....it should be filtering the frame by dropping it at port FA09 due to their being two MAC addresses associated with the FA09 port in the MAC address table. By filtering, the switch is doing it's job of restricting network communication to the segment where the frame is originating and where the intended destination happens to be..in this case hosts A and B connected to the hub.

 

In other words the question to which port is the frame forwarded should not apply.