200-301 ccna 180-day exam preparation

200-301 ccna 180-day exam preparation.For example, looking at Figure 3-1 again, PC1 sends a packet to PC2, and then PC2 answers to PC1, in six routing steps. In this example, although it is certain that R2 should receive the packet, the packet never reaches PC2 O Therefore, the problem needs to be further isolated by carefully examining the 3rd routing step between R2 and PC2. This process of narrowing down the cause of the problem is called problem isolation.After isolating the problem to the IP forwarding step (as shown in Figure 3-1), the problem should be isolated to several smaller areas if possible. For example, if R2 receives packets but PC2 does not, the problem could be in R2, SW4, SW5, PC2,cable, or possibly the network3.2 Basic Content 53devices that were overlooked in the network information.The process of further isolating the problem requires, in particular, consideration of the functions of the layers of the OSI model, as well as the functions of the data platform and the control platform. R2 needs to be informed of PC2's MAC address via Address Resolution Protocol (ARP). If it is found that R2 is not reaching PC2's ARP entry, it should be expected that there is likely an IP-related fault. This problem could be caused by any of the following.It could be a SW4-SW5 trunk break. It could be that the SW5-PC2 cable is broken. It could be that the PC2IPv4 configuration does not set the 2P address of PC2.It could be that the Dynamic Host Configuration Protocol (DHCP) server is misconfigured such that PC2 cannot obtain a DHCP address. Problem isolation refers to a process that starts with a general idea and then becomes increasingly specific. In this example, the problem can be isolated to the point where it is clear that R2's PC2APR request has failed, but based on the description, it is not yet possible to determine the specific cause of the ARP failure. If the test question does not provide any clues to get started, the following process can be followed, which summarizes the isolation strategy for routine systemic problems. Step 1 Start by examining the Layer 3 data platform (IP forwarding) and comparing it to the expected normal operating results until the failure in the first major routing step is identified. Step 2 Isolate the problem into several smaller scopes, if possible. a.Check the functionality of all layers, but focus on Layer 1, Layer 2, and Layer 3. b.Check the functionality of the data platform and the control platform.Keep in mind that no amount of good troubleshooting will earn you extra credit on the exam; all you have to do is pull out all the stops to find the answer, and sometimes you can even guess a thing or two based on the context of the test question. For example, Step 2a suggests focusing on Layers 1, 2, and 3, since the CCNA exam focuses primarily on these three layers. Of course, you can also discover as many shortcuts to the entire process as possible based on the content of the test description.The final step of the 3-step process is the root cause analysis, which aims to identify the devices and functions that need to be fixed to finalize the troubleshooting process. The root cause is the real cause of the failure, and more importantly, by fixing the root cause, the failure problem is solved. Finding the root cause is important because the root cause is fixable. For example, continuing to consider the previous example, R2 is unable to forward packets to PC2, and the list of problems identified through problem isolation is as follows. R2 is unable to forward packets to PC2. R2 is not receiving an ARP answer from PC2. The trunk interface from SW4 to SW5 is in the down/down state. The wrong wire sequence is used for the cable between SW4 and SW5. All of the above statements could be correct for a particular problem situation, but only the last one has an obvious solution (i.e., use a cable with the