Minus 1! Question's wording...

dazerski

I was doing the chapter intro questions in Odom's ICND1 book on Chapter 7.

5) PC1, with MAC address 1111.1111.1111 is connected to switch SW1s Fa0/1 interface, PC2, with MAC address 2222.2222.2222 is connected to SW1s Fa0/2 interface. PC3 with MAC address 3333.3333.3333 connects to SW1s Fa0/3 interface. The switch begins with no dynamically learned MAC addresses, followed by PC1 sending a frame with a destination address of 2222.2222.2222. If the next frame to reach the switch is a frame sent by PC3, destined for PC2s MAC address of 2222.2222.2222, which of the following are true?

a. The switch forwards the frame out of int Fa0/1
b. The switch forwards the frame out of int Fa0/2
c. The switch forwards the frame out of int Fa0/3
d. The switch discards (filters) the frame.


So I know that in this case, the switch would flood the frame out every port except the one it came from, so A & B are correct. But I doubted myself because to me, the questions seemed like a "Pick One Answer" question. Maybe its my bad grammar but if it only wanted one answer, would it have said "Which of the following IS true"? It seems like this goes beyond Cisco topics and more on how I misread the question. But I really hope they make it more clear to people like me when to pick more than one answer or not. However, if I didn't doubt what I clearly understood, then I should have known it was two answers instead of just one... Grrrrrrr....

dynamik

I don't know about the Cisco tests, but on the Microsoft tests, I've gotten questions that have six or seven possible answers with only, "Choose all that apply." It could be one. It could be four or five. You should focus on learning the material, so you can answer correctly regardless of how the question is worded. I wouldn't count on the test helping you narrow down the options.

AlexMR

I've read several times that in cisco exams they ask specifically for how many answers they want. The practice questions in both "Interconnecting Cisco Network devices" dont specify how many answers are valid, somehow making it harder, since you cant just eliminate the obvious wrong ones and pick the most likely answer.

Cessation

Wouldnt the answer be B?
If PC1 already sent frames to PC2 then PC1 would have flooded already and the switch would have dynamically picked up all mac adds from the replys.

Then they say the next frames from PC3 need to go to PC2.
Since the switch should have picked up the all the frames from the flood would'nt the switch just send the frame straight to PC2?

shednik

dynamik wrote:

I don't know about the Cisco tests, but on the Microsoft tests, I've gotten questions that have six or seven possible answers with only, "Choose all that apply." It could be one. It could be four or five. You should focus on learning the material, so you can answer correctly regardless of how the question is worded. I wouldn't count on the test helping you narrow down the options.

I'll definitely say though that Cisco exams are much more straight-forward then MS exams, I'd prefer Cisco's over MS any day. My suggestion is to look at the answers to a question and choose the best ones, there are some questions that will catch you by surprise but if you know the material you will do fine. I studied hard for my Cisco exams and then felt over prepared for the exams.

shednik

Cessation wrote:

Wouldnt the answer be B?
If PC1 already sent frames to PC2 then PC1 would have flooded already and the switch would have dynamically picked up all mac adds from the replys.

Then they say the next frames from PC3 need to go to PC2.
Since the switch should have picked up the all the frames from the flood would'nt the switch just send the frame straight to PC2?

A switch builds it's mac address table off the source address of frames not by flooding and waiting for a reply. Once PC 2 sends a frame to PC1 or PC3 then the switch will learn the Mac address for PC2.

mikej412

Cessation wrote:

Wouldnt the answer be B?

ddzierzek wrote:

The switch begins with no dynamically learned MAC addresses,

followed by PC1 sending a frame with a destination address of 2222.2222.2222.

If the next frame to reach the switch is a frame sent by PC3, destined for PC2s MAC address of 2222.2222.2222, which of the following are true?

Until PC2 responds, the switch doesn't know which port PC2 (or MAC 2222:2222:2222:2222) is on -- so it still floods

If you build a paper switch with a paper cam table and write the mac addresses in the paper cam table following those steps above -- you still won't have a 2222:2222:2222:2222

Empty cam table

PC 1 sends, so the switch learns 1111:1111:1111:1111. is on FA0/1

PC3 sends, so the switch learns 3333:3333:3333:3333 is on FA0/3

Practice questions can actually be harder when they don't tell you the number of correct responses -- but the purpose is to make you think and, in cases like this, shock you so that you remember the REAL SOLUTION if you fell for the "easy answer" or the "half-ass answer."

On the real exam (check the Exam Tutorial Link in the CCNA Forum FAQ) if there is one answer you get a radio button, if there are multiple answers you get the check box. And it tells you on all the exams below the CCIE Written Exam how many answers are required.

nel

So I know that in this case, the switch would flood the frame out every port except the one it came from, so A & B are correct. But I doubted myself because to me, the questions seemed like a "Pick One Answer" question. Maybe its my bad grammar but if it only wanted one answer, would it have said "Which of the following IS true"? It seems like this goes beyond Cisco topics and more on how I misread the question. But I really hope they make it more clear to people like me when to pick more than one answer or not. However, if I didn't doubt what I clearly understood, then I should have known it was two answers instead of just one... Grrrrrrr....

ive also felt this to be the case for several questions throughout the ccent book. silly i know but at times it felt like i am way of being prepared because of this. unless it is a cisco ploy to make you overprepared