AFAIK if stronger team beat weak team (if rating difference btwn two teams is more than 40) then strongest team earns +10 own rating point with their previous rating points.
For ex. Pak playing vs Bangladesh... Last T20I Ranking Updated on 6th Sep
Pak Rating Point : 121 (2417/20)
Ban Rating Point : 78 (1168/15)
If Pak wins then 121+10=131...
With addition of 2417+131= 2548/21= 121
If Ban wins then 78+90=168
With addition of 1168+168=1336/16=84
Above example took only because difference between both team is more than 40 rating points.
*I know if ranked team plays with unranked team.