https://www.jpl.nasa.gov/news/nasas-tech-demo-streams-first-...
https://www.lpi.usra.edu/opag/july2014/posters/9-DSOC_OPAG_P...
The first line is around 267 Mbps, so it looks like they're expecting 10 Mbps at max distance to Mars.
Earth to Mars ranges from 5.5*10^10 to 4.0*10^11 m, and light travels 3*10^8 m/s.
Earth-Mars latency is therefore from 3 to 22 minutes one-way.