Preheat oven to 475 F. Sprinkle the ribs with salt and pepper and place in a single layer in a shallow roasting pan, meaty side up. Roast until very brown, about 1 hour, turning once to brown both sides. Remove from pan. Pour off fat from roasting pan. Place pan over high heat; add water and cook, scraping up all the browned bits from the bottom.
Place the ribs and pan juices in a large stockpot along with the other ingredients, adding just enough water to cover. Bring to a boil over high heat, then reduce to medium-low; cover and simmer until the meat and vegetables are very tender, about 2 hours. Strain through a colander or sieve. Discard meat and vegetables. Skim fat off broth. (I usually chill the broth in the refrigerator so that the fat congeals on top. Makes it very easy to remove. However, if you want to use the broth that day, you can use one of the many methods for removing fat from liquid.)
Reductions: At this point, there are several options. You can use or freeze the broth as is. If I am going to store it in the freezer for a soup broth, I reduce it by boiling, uncovered, until it will fit in a particular container. Then I add water when I use it. Sometimes I make a demiglace. That requires further reduction, until the stock is very thick and almost syrupy. I freeze it in ice cube trays and place the frozen cubes in a plastic bag for storage. One of those cubes is great for use in a sauce.
Note: Years ago, you could purchase meaty soup bones from the butcher, or even the supermarket, that were inexpensive and full of flavor. If you can get those, by all means, use them instead of ribs. These days, the only bones I see have no meat, therefore, little flavor. So, I wait until the ribs are on sale and use them. Although you end up discarding the meat, it is well utilized because all of the flavor is transfered to the broth.