Appropriate logs and metrics to assess network performance and reachability issues (for example, packet loss)

What are some key metrics that you would monitor to assess network performance on AWS?

Key metrics to monitor include Latency, Throughput, Packet Loss, Jitter, and Error Rates. These metrics can be obtained from AWS CloudWatch, which provides detailed monitoring for AWS services like Amazon VPC, Direct Connect and VPN connections. By keeping an eye on these metrics, you can assess the performance of the network.

How can you use Amazon CloudWatch to identify packet loss on your AWS network?

Amazon CloudWatch allows you to monitor network packets in/out and dropped packet count metrics for your EC2 instances, which can indicate packet loss. By creating alarms based on these metrics, you can be automatically notified if packet loss thresholds are exceeded, prompting further investigation.

Can AWS VPC Flow Logs be used to detect network reachability issues? If so, how?

Yes, AWS VPC Flow Logs capture information about the IP traffic going to and from network interfaces in your VPC. By analyzing flow log data, you can identify traffic patterns, such as rejected connection attempts, that may point to network reachability issues.

What role does AWS Network Performance Monitoring play in understanding packet loss and how is it accessed?

AWS Network Performance Monitoring (part of AWS CloudWatch) helps in understanding packet loss by providing visualization and insights about the network health of your resources. Metrics like dropped packet counts can directly indicate packet loss. These metrics are accessible via the AWS Management Console or the CloudWatch API.

When investigating packet loss issues in AWS, how would you determine if the problem is with the service provider or within your VPC?

To determine the source of packet loss, you can perform a traceroute or MTR (My Traceroute) from your instance to an external destination. If packet loss occurs within the AWS network, the issue may be with the AWS infrastructure or configuration; if packet loss occurs outside AWS, the problem may be with the service provider. Additionally, checking AWS Service Health Dashboard and Direct Connect operational status can also provide information on where the issue lies.

How can you set up alerts for anomalous network activity that could hint at performance degradation or reachability issues?

You can set up alerts in Amazon CloudWatch based on metric thresholds that reflect anomalous network activity, including high error rates or unusual changes in latency or packet loss. These alerts can be customized to specific thresholds and will trigger notifications when those thresholds are breached.

What is the significance of the TCP Retransmission rate and how can it help in determining network issues?

The TCP Retransmission rate is significant because it indicates how often packets are being retransmitted due to being lost or not acknowledged. A high rate of TCP retransmissions can signal network congestion, overloaded servers, or packet loss issues, which can affect connectivity and performance.

In the AWS environment, what is the importance of tracking the Request and Response Time metric, and how can it be correlated with network performance issues?

The Request and Response Time metric is important as it indicates the latency between a client request and the server response. This metric can be correlated with network performance issues; for instance, longer response times may suggest network congestion, poor routing, or server performance issues. Monitoring and analyzing this metric can help troubleshoot the root cause of latency.

What can be inferred from “Amazon Route 53 Health Check” regarding network reachability, particularly packet loss?

Amazon Route 53 Health Checks monitor the health and reachability of your endpoints. If health checks to an endpoint fail, this may indicate network reachability problems which could include packet loss. These health checks can be configured to identify and alert on such issues promptly.

Describe how you would use Amazon CloudWatch’s “NetworkPackets” metrics to distinguish between normal traffic patterns and potential network problems?

Amazon CloudWatch’s “NetworkPacketsIn” and “NetworkPacketsOut” metrics reflect the number of packets transferred to and from an instance. By establishing baselines for normal traffic patterns, you can detect deviations indicating network problems. A sudden drop in these metrics could suggest packet loss or blocked connections, while an unexpected spike might indicate a surge in traffic or a potential security threat.

Remember that when preparing for the AWS Certified Advanced Networking – Specialty exam, it’s crucial to not only understand what metrics and logs to look at but also how to effectively implement and interpret them within the AWS ecosystem.