A siege is a military blockade of a city, or fortress, with the intent of conquering by attrition, or by well-prepared assault. Siege warfare is a form of constant, low-intensity conflict characterized by one party holding a strong, static, defensive position. This party is called a garrison. The attacking party is said to be laying siege and those on the defense are under siege. Consequently, an opportunity for negotiation between combatants is common, as proximity and fluctuating advantage can encourage diplomacy.