SUM of trafic rate

How to SUM two or more trafic rate interfaces inbound and outband in the same graph ?
i use Grafana, i have not the same result with collectd/graphite

regards

@dilde Theres not enough information here for me to help you. Can you please add some more detail? Also from what it sounds like you are trying to do I would suggest you use telegraf to collect your metrics.