Exam N10-008 topic 1 question 306 discussion

CRC Errors = Faulty Cable = Physical = Layer 1

The question stated "Administrator MOST likely start to troubleshoot when a network is experiencing a number of CRC errors?, therefore, the answer will be letter A. Start from Bottom to Top.

According to CompTIA Network+ N10-008, CRC (Cyclic Redundancy Check) errors typically indicate issues at Layer 2 of the OSI model, the Data Link layer. This layer handles error detection and correction for data as it moves between nodes on a network. The presence of CRC errors suggests that frames are arriving corrupted due to issues such as faulty network interface cards (NICs), bad cables, or interference

I will have to go with A, troubleshooting 101 based on 30 years of experiences…always tackle the simplest issue first…it’s easier to change out the cable than it is to mess with stuffs in “layer 2”. So I would definitely start my troubleshooting at layer 1 before trying to mess with things in layer 2…

I think people are confused because the DETECTION of CRC happens in Layer 2, however, the CAUSE is almost always Layer 1, a physical issue like bad cable, bad port, bad NIC. Which means, if you get CRC errors, you'll almost always look there first, most likely replace the cable, then go from there. Cisco says the same if you look for CRC troubleshooting.

Initially I picked “B” but looking at these comments I am so confused now LMAOO

Messor says B however, this question on the test actually doesn't have layer 2 as an option

i say layer 2 question the obvious or as professor messer says "start with the obvious" crc= bad layer 2 hardware https://www.youtube.com/watch?v=L-hlrK9Dq7I

B Layer2

More or less the same as earlier question 7. "A network is experiencing a number of CRC errors during normal network communication. At which of the following layers of the OSI model will the administrator MOST likely start to troubleshoot?" Correct answer B - layer 2

OSI layer 2 data units are called frames and Layer 3 data units are called packets, Layer 4 are segments. CRC refers to frames and thus to Layer2 Errors.

B. Layer 2 CRC (Cyclic Redundancy Check) errors typically occur at the data link layer, which corresponds to Layer 2 of the OSI model. Therefore, when troubleshooting a network experiencing CRC errors, the administrator would MOST likely start at: Layer 2 includes protocols such as Ethernet that deal with the framing and addressing of data on the local network segment. CRC errors often indicate issues with the integrity of the data as it is transmitted across the network at this layer.

In question 7 there is normal network communication in progress going on, you would only be able to troubleshoot layer 2 without causing interference. If there is not normal network communications going on like in this question, you can check the layer 1 cables, ports & transceivers.

In question 7 there os normal network communication in progress going on, you would only be able to troubleshoot layer 2 without causing interference. If there is not normal network communications going on like in this question, you can check the layer 1 cables, ports & transceivers.

CRC errors occur from misconfigured, or simply malfunctioning cables on layer 1. CRC-4 checks for data transmission errors on E1 trunk lines at the data link layer (Layer 2) or transport layer (Layer 4) of the OSI model for how applications communicate over a network. An error is said to have occurred when there is a mismatch between the receiver's information and the sender's information, thus involving the frames. Question 7 said this was layer 2 so that's weird, lol.

CRC errors are usually caused by interference. This interference might be due to poor quality cable or termination, attenuation, mismatches between optical transceivers or cable types, or due to some external factor These issues are on Layer 1

it doesnt make sence to start at 2 be we dont know what is the problem but we do know the possoble cause, and when trobloshooting you start with the simple obvios fix before excleating