switches - interface status - speed mismatch

superbabe_uk

Hi,

I'm a bit confused as to the interface status for a speed mismatch, duplex mismatch and encapsulation mismatch.

In Wendell Odom's study guide it says the int status for speed mismatch is DOWN / DOWN , however in a CCNA exam practice question I saw the answer should be UP / DOWN.

The study guide also mentions that with a duplex mismatch the int status would still be in an UP / UP state but when I tried it in packet tracer both interfaces went DOWN / DOWN.

same goes for encapsulation - I'm a bit confused as to what would be the correct answer in the exam ?

many thanks for your help !!

odysseyelite

I thought I read in Odom's book they would be up and up. I know in my lab I had a mismatch on my 3640 and 2950. It was operational but there were a lot of collisions and gave me a ton of messages. I never understood why it would not work in full duplex because the NIC supported it.

Packet tracer does not always do exactly what a physical lab would do.

For encapsulation, I beleive it would be a up\down state. I know I just had a pratice sim on that one.

themagicone

The up/down status can help determine the level of problem. If it is down/down it is a physical layer problem. up/down is a layer 2 problem. A mismatched duplex/speed can cause a layer 2 problem. Or that is my thinking at least.