Simple Metric Aggregation to Determine Delta Values in Kibana

I am passing network metrics to my ELK stack. Some data is presented in counters; always incrementing the bits sent, for example. However, I need to display the rate of change in these counters over a fixed sampling period (e.g. a gauge that tells me the current bitrate).

Is there a way in Kibana to do rather-simple metric aggregation such as this? I see that scripted aggregations are possible in Elasticsearch, but from what I've read, this is not supported when using Kibana as the frontend.

If this is not feasible with Kibana, does anyone have recommendations for using another tool to determine the delta values, which can then be passed to ELK? Thanks for any help/advice.

I'm using the most-recent non-beta stack and the devices I'm monitoring don't appear to be configured (from a FW standpoint) to display gauges (delta values) in regards to these counters.

Timelion can do this for you, but native KB cannot.

You're right, Timelion looks like it can produce the derivative of the data, which is what I need. However I can hardly find any documentation on installing or configuring it. I've read I just need to install it as I would Marvel, but it's disconcerting not having any real documentation on it, as I'd find with most supported plugins.

It's not supported, it's still essentially an alpha.