Depending on the thickness of the red colour, this will be either staining or flashing. Staining, which is the thinner of the two was by means of metal oxides - either painted on or the item could be dipped into the colour, then fired to fix the colour........ Egermann was the big cheese who I think invented this process somewhere c. 1830s, but it continued to be produced for much of the C19.
Flashing is the less expensive of the two methods and does involve a thin layer of coloured glass onto the clear base glass............ Hoffman was a big producer for flashed wares, and both these were Bohemian producers, and I could be wrong but most stained and flashed glass seems to be ruby red, but I think you can find it in yellow.
Designs on both stained and flashed glass were created by cutting or probably more usually copper wheel engraving, through the red, to expose the clear glass beneath. I suppose both processes could be called casing but they are usually referred to as above, and were big in fashion in the second half of the C19 - but like most stuff it probably went on for some time after.
Try googling these names and you should get enough to read till bedtime