Root Cause Analysis (RCA) - Alert Based Workflows
Overview of Framework
This knowledge base article is to explain the different sections of the various Alert RCA's available in the new RCA framework. Following the Overview will list the current RCA's available in the framework and explanations of their respective workflows.
How to engage
Customers will be presented with 3 entry points to begin the RCA process. The Alert Hub, Device Details Page, and the Organization Alerts Page will have entry points. Both the Alert Details and Take Action Link/Button will take you into the RCA side drawer workflow.
What do customers see?
When entering the RCA workflow a new side drawer will open to guide you through the process that has been curated for this specific alert. Below the alert title there are 2 tabs for the sections Alert details and Suggested Actions. Depending which link/button you selected previously, you will land in one of these sections to begin, and you can freely move between them.
AP Ethernet uplink speed degraded
Alert Description - Access point connected to the 10/100Mbps speed Ethernet connection
The performance of an Ethernet can significantly influence a wireless network's overall effectiveness and efficiency. Ethernet connections can have various speed and duplex permutations, such as 10 Mbps, 100 Mbps, 1 Gbps, 2.5 Gbps, and 5 Gbps, with either Half or Full Duplex modes. These parameters are established through a negotiation process between connected devices. However, if this negotiation fails, the devices may not achieve their optimal speed and duplex settings, leading to suboptimal network performance.
Modern Wi-Fi standards, such as Wi-Fi 6 and 6E, support speeds exceeding 1 Gbps, with Wi-Fi 6E Access Points (APs) typically requiring a minimum Ethernet speed of 2.5 Gbps to function effectively. If an AP's Ethernet connection is limited to 10 Mbps or 100 Mbps, it will significantly impact wireless performance. This creates a bottleneck, preventing the AP from fully utilizing its high-speed wireless capabilities and ultimately degrading overall network efficiency and user experience.
The below image shows a trend view of the Ethernet port's current speed. The top line graph shows Red highlights timeline trend when the the AP has alerted about the negotiation failure. This page also shows the number of clients impacted when alert is first reported. By clicking on Clients Impacted, It will display the clients that were connected to this particular AP. there is another trending chart, indicate average wireless data rate from all clients that has been connected to this AP during the period of alert. Network administrator can assess actual performance impact and bottleneck by comparing connected wireless data rate vs. Ethernet uplink data rate
Suggested Actions for AP Ethernet uplink degraded on Cisco Meraki MS Switches are as follows:
Troubleshooting assistance in each suggested action can only be performed to its full capability while the AP is connected to a Cisco Meraki MS Switch. 3rd party switches will not have an active test capabilities but alert detail can display connected 3rd party switch details and suggested actions.
Make sure to have the required network access to take the required actions from the suggestions.
1. Cable Test: This will test out the cable and the switch port connection where the AP is connected to.
Once you run the cable test, it will list out all the parameters it was able to identify and different test run results as shown below:
2. Update link negotiation settings: This action allow network administrator to force specific speed and negotiation settings on AP connected switch port without leaving suggested action page.
If the negotiation was successfully changed on the switch and establish faster than 1 Gbps full duplex speed, the Alert will be automatically moved to resolved condition.
3. Cycle port on switch: This action will turn off and on the the switch port, force AP to reboot and restart Ethernet negotiation.
This action will power down the access point momentarily. Make sure to run this during a maintenance window
Once the port has powered back on, the Access point has renegotiated speed. If the port cycling helped negotiate the right speed for the AP, the alert will be resolved.
Suggested Actions and Test Assistance for 3rd Party Switches:
1. Cable Test: This will test out the cable and the switch port connection where the AP is connected to. This test would identify the uplink switch and prompt you to check if the cable if damaged or not.
2. Check auto-negotiation in switch port settings: This recommendation is to verify if your switchport is configured to Auto-negotiation or the right speed.
3. Cycle port on switch: This recommendation is to the power cycle of the switch port where the access point is connected.
Cyclic Redundancy Check (CRC) errors detected
CRC is used as a means of detecting errors in transmitted data.
The sending device generates a value derived from the remainder of a polynomial division of its data contents. The receiving device compares the recalculated CRC value with the one received along with the data. If the two CRC values match, it indicates that the data hasn't been corrupted during transmission.
When the receiving device detects a mismatch between the received CRC value and the recalculated CRC value, it flags a CRC error. Seeing CRC errors reported by the Meraki switch on the dashboard indicates that the data may have been altered or corrupted during transmission. 
Guided Troubleshooting Flow
This feature is designed to reduce troubleshooting effort, make issue resolution more intuitive, and save more time for our customers. Guided CRC troubleshooting flow automates and outlines suggested action items (refer to flow diagram and the short video below) to be performed to resolve CRC error alerts. This tool is designed to help network administrators efficiently and effectively identify the root cause of the CRC error on switch ports and resolve it.
The issue/alert wil be shown in several areas. One of them being the switch details page itself:
The dashboard will also prompt and highlight the issue within the Alert Hub -> drop down. This drop down will allow you to troubleshoot the issue regardless the page you are currently viewing. From here you will be able to view the alert, details and suggested actions.
The details section will highlight the timeframes within the last 2 weeks at which this alert was triggered.
The suggested actions section will allow you to perform several actions to help rectify the alert.
1. The first item would be a validation of link negotiation between the 2 devices. If a mismatch of configuration is found it could be corrected from this drop down itself, instead of having to navigate to each switch and switch port page to make the required changes.
2. In the event the link negotiation configurations do match between the connected devices we will then suggest a cable test to verify the integrity of the physical cable itself.
You are not allowed to run the cable test on your uplink port because it will disrupt traffic
3. More suggestions will be listed within the drop down to help you identify the root cause of the issue:
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