Keep in mind however that the Duke can only obligate that his vassals contribute forces that their oaths of Homage guarantee (this is the contract between the lord & his vassals). If the vassals are smart & actually care about their own personal territorial integrity, they'll have MORE assets available than what their feudal obligation requires. FREX lets say the local baron has an obligation of 1 Bn of light hovertanks & 1 Bn of rifle infantry, to be called up for service for defense of the planet in the case of invasion (or other operations -- depending on the actual agreement). Depending on the location of the world & the likelihood of being invaded, that local baron might have an entire REGIMENT of tanks & a regiment or two of rifle infantry available as assets, giving him a powerful force left aside for local defense. I would imagine nobles on border areas likely to get invaded would do this precise thing, whereas ones in the interior or likely not to get invaded would have only slightly more than their obligation. I would imagine FedSun barons in the Crucis March busily soiling themselves in terror during the 1st SW as they realize how inadequate their military assets were the Dragon comes pounding down the street (and start clamoring for as many mercs as they can get their hands on)...
Damon.
Of course the local barons have more. The discussion in this thread has meandered a bit here and there. Somebody upthread made the argument that even after you've supplied whatever forces you were supposed to provide, other nobles can call on you for more support. I disagreed.
What military obligations you're supposed to fulfill will vary from planet to planet and era to era. On some no-name world in the midst of the 3rd Succession War, a low ranking noble is probably supposed to provide something like one or two mechs. Of course, he's going to want forces to protect his own property as well. I tend to inflate Battletech army sizes to what I consider more "realistic" (ha ha) levels by doing this. Because you've got a lot of little guys protecting their own interests, the overall forces appear smaller than they really are.
So let's go for a quick and dirty example.
Mudball VIPopulation: 80 million
Ruler: Duke Dimwit III
Other nobles: Barons 1-5
Major cities: Capital City (10m), Springfield (2m), Brockway (1.5m), Ogdenville (1.5m), North Haverbrook (1.5m)
Official defending forces (provided by the Duke): 2 Battlemech companies, 1 battalion Scorpion tanks, 1 regiment infantry (with transport vehicles), 4 ASFs
Forces supplied by Baron 1: 2 Battlemechs
Forces supplied by Baron 2: 1 Battlemech, 2 Hunter Light Support Tanks
Forces supplied by Baron 3: 1 Battlemech, 4 Warrior H-7 VTOLs
Forces supplied by Baron 4: 2 Battlemechs
Forces supplied by Baron 5: 2 Battlemechs
Additional forces on planet:
-Each baron has a lance of light vehicles and a battalion of infantry he keeps on his own lands. Barons 1-3 have a little more wealth, and each retains a pair of light mechs as well.
-The Advanced Optics Medium Laser factory retains a lance of mechs (2 Jenners, 2 Phoenix Hawks) a lance of Striker tanks, and 2 companies of infantry.
-The Duke has a lance of medium/heavy mechs, 6 Mechbuster fighters, 2 lances of Saladin hover tanks, and a battalion of infantry as his "personal guard" that doesn't leave his castle grounds.
-Capital City maintains a lance of Urbanmechs and a regiment of foot infantry.
-Springfield has 2 Stinger mechs and a Wasp, and a battalion of infantry.
-Brockway, Ogdenville, and North Haverbrook each keep a battalion of infantry and a pair of light mechs.
-There are approximately 20 regiments of foot infantry and 5 regiments of very light vehicles (too weak for real record sheets -- treat as mechanized infantry) scattered about the planet. These units have assigned positions around the planet and so are never concentrated in any one area. At most, attackers will face a few companies in any one place.
-There is also an air force of 24 Defender Medium Strike Conventional Fighters. Like the infantry, these are spread around the globe and the most an attacker is likely to face is 4-6 fighters.
-There are also approximately 1 battalion of combat vehicles, and 5 or 6 mechs that are in private hands (i.e., organized crime, lone nutjob survivalists, etc) that are completely off the books and nobody is aware of them.
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If you look at the forces of Mudball VI on paper, you're likely to just see the Duke's forces and the reinforcements by the 5 barons. So almost a full Battlemech battalion, a battalion of light tanks, and a regiment of infantry. This is what shows up on the viewscreen when military strategists are looking over the planet. And most of the time, that's all you have to worry about facing. The rest of the forces are people's personal household guard (or corporate defense forces, or the mech grandpa keeps in the barn), and they aren't going to march out to meet you unless you are attacking something they want to protect. Half the forces on planet are not interested in taking on every little invasion that occurs.