Frustrated with a certain type of VLSM question

veritas_libertas

Guys, I can do very well at Summarizing, creating a VLSM network, and knowing what type of CIDR address is needed, but these type of questions REALLY throw me off. Does anyone have an approach they share that doesn't take 5 mins out of a 70 min test :P

sratakhin

Answer A is also correct because that network is the last subnetwork the subnet can have.
Answer B is wrong because you won't be able to fit smaller networks if you already have a class C network with the network address 172.20.255.0
The two class C networks will have to be 172.20.254 and 172.20.253, so answer C and E are incorrect.

I just went over the answers one by one and found which requirements can and can't be met.
5 minutes is fine for this types of questions. You could it faster with a lot of practice though, but you'll have a plenty of time on the exam. I finished mine in less than an hour.

2URGSE

sratakhin wrote: »

Answer A is also correct because that network is the last subnetwork the subnet can have.
Answer B is wrong because you won't be able to fit smaller networks if you already have a class C network with the network address 172.20.255.0
The two class C networks will have to be 172.20.254 and 172.20.253, so answer C and E are incorrect.

I just went over the answers one by one and found which requirements can and can't be met.
5 minutes is fine for this types of questions. You could it faster with a lot of practice though, but you'll have a plenty of time on the exam. I finished mine in less than an hour.

How can answer A be correct? It is overlapping with the network address range of answer B.

B range is 1 through 254

A range is 253 to 254 (252 is network address, 255 is broadcast)


2. You could use the networks in B and C to satisfy the LAN's on the right, but the question does not say how many answers they are looking for.

Unless I am missing something here...............

sratakhin

The question states that you should allocate the smallest subnets first. If you choose the answer B, where are you going to put your WAN links?

goldenlight

Don't you just love Cisco Questions. You truly have to think about each one.

2URGSE

sratakhin wrote: »

The question states that you should allocate the smallest subnets first. If you choose the answer B, where are you going to put your WAN links?

You're right, you can use B and C, but not B and A (which was my point).

I can see why the OP is frustrated, sometimes their questions are just plain annoying. Plus they didn't say how many solutions they are looking for (2, 3 more?)

sratakhin

If the questions were way too simple, what value the certification would have?

P.S. Microsoft way of asking questions is even more annoying.

goldenlight

What section of CCNA did this problem come from?

I need to study up on problems similar to these.

veritas_libertas

Variable Length Subnet Masking (VLSM)

2URGSE

sratakhin wrote: »

If the questions were way too simple, what value the certification would have?

P.S. Microsoft way of asking questions is even more annoying.

Agree, they should not be easy, but the question could have been written a little bit more clearly.

Not going the Microsoft Cert path , at least not anytime soon.

2URGSE

Can anyone find more VLSM questions and post them? (perhaps in another thread, I don't want to hijack this one)

veritas_libertas

2URGSE wrote: »

Agree, they should not be easy, but the question could have been written a little bit more clearly.

Not going the Microsoft Cert path , at least not anytime soon.

LOL, I had to laugh at this. While the Cisco exams are not easy, I have found their questions to usually be more clear.