如何跟踪EC2实例或弹性IP上的公共带宽使用情况？

I am looking into finding a way to track public bandwidth usage on a per-instance or per elastic IP basis. Amazon does not seem to offer these metrics. You can get total in/out bandwidth through their reporting mechanisms, but this includes private network bandwidth, and is account wide. You can use cloudwatch to gather more in depth metrics, but they also lump public and private bandwidth together. We are looking into rolling our own, but your servers are built with one interface, and any elastic IPs are NAT’d to that interface. Since everything goes through one interface, it is all lumped together.I am looking into finding a way to track public