EC2 c7gn instances degrade in network performance throughput

Question

At some point c7gn( large type ) instances start degrading network throughput, so data transferring is throttled, and even scp a small file to a server stop working.( Instance is in use for WS connection). Based on instance monitoring tab it looks like only showing that instance already has been affected by some throttling based on network out bytes/network out packets charts. I assume there is some cap for network usage for some instances in units( like for small instances for CPU and Memory ). If it is true where can i find network units usage for the instance ? and how to check how much quote already has been used ?

Answer

You can refer to [Compute optimized instances documentation](https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/compute-optimized-instances.html#compute-network-performance) about network performance.  As per the table, c7gn.large is indicated with a †, i.e. it has a baseline bandwidth and can use a network I/O credit mechanism to burst beyond their baseline bandwidth on a best effort basis. For more information, refer to [Amazon EC2 instance network bandwidth](https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/ec2-instance-network-bandwidth.html)

```
>aws ec2 describe-instance-types --filters "Name=instance-type,Values=c7gn.large" --query "InstanceTypes[].[InstanceType, NetworkInfo.NetworkPerformance, NetworkInfo.NetworkCards[0].BaselineBandwidthInGbps]" --output table --region us-east-1
--------------------------------------------
|           DescribeInstanceTypes          |
+-------------+--------------------+-------+
|  c7gn.large |  Up to 30 Gigabit  |  6.25 |
+-------------+--------------------+-------+
```

You can use CloudWatch as per [Collect network performance metrics](https://docs.aws.amazon.com/AmazonCloudWatch/latest/monitoring/CloudWatch-Agent-network-performance.html) to monitor network metrics that may exceed maximum allowed

EC2 c7gn instances degrade in network performance throughput

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