Correct answer this easy question?

MaddogZ

This question is from wendell odoms cisco press INTRO book. Chapter 3 Quiz question 2.

Which of the following are part of the functions of OSI Layer 2 protocols?
a. Framing
b. Delivery of bits from one device to another
c. Addressing
d. Error detection
e. Defining the size and shape of Ethernet cards

I picked A and D (Framing and Error detection) because ethernet has a FCS for detecting if error occured. But the answer given in the book is only A.

Pash

The question is a little vague but there again many cisco questions are there to fool you in the real exam, tbh id say that factual questions are actually the hardest to answer compared to the proper troubleshooting questions.

I would say as the question doesn't hint towards the use of switching (ie store and foward switching), then negate error detection as an answer and stick with framing.

rossonieri#1

MaddogZ wrote:

This question is from wendell odoms cisco press INTRO book. Chapter 3 Quiz question 2.

Which of the following are part of the functions of OSI Layer 2 protocols?
a. Framing
b. Delivery of bits from one device to another
c. Addressing
d. Error detection
e. Defining the size and shape of Ethernet cards

I picked A and E (Framing and Error detection) because ethernet has a FCS for detecting if error occured. But the answer given in the book is only A.

A and C (C? -> MAC)

E is correct - but it was more on PPP functionality ( which is also true in L2)

james_

OK, maybe you are reading an outdated version of the CISCO Press book?

My answers for the same question are:

a. Framing
b. Delivery of bits from one device to another
c. Logical Addressing
d. Error Recovery
e. Defining the size and shape of Ethernet cards

Notice c and d.

Logical (not physical) addressing refers to IP addresses, Layer 3.
Error Recovery (not detection) generally refers to the Transport layer, and TCP

So out of the above, only a. Framing is applicable.
Hope this helps!

Pash

james_ wrote:

OK, maybe you are reading an outdated version of the CISCO Press book?

My answers for the same question are:

a. Framing
b. Delivery of bits from one device to another
c. Logical Addressing
d. Error Recovery
e. Defining the size and shape of Ethernet cards

Notice c and d.

Logical (not physical) addressing refers to IP addresses, Layer 3.
Error Recovery (not detection) generally refers to the Transport layer, and TCP

So out of the above, only a. Framing is applicable.
Hope this helps!

exactly, remember host to host layer 4 is your error recovery.

MaddogZ

Im reading the 2004 edition of cisco press INTRO.

Back to my question its says ERROR DETECTION not error recovery which i know is Transport layer function. However error detection can be done in layer 2 because of the FCS.

Spudage

Goto the Cisco Press website and follow the links to the errata for your particular version of the book. You'll probably find that they have corrected it since the book was published.

For technical books it's always a good idea to look up the errata. It can mean the difference between understanding a topic and not having a clue (due to errors)