Noin-Ula burial site
Many immigrants lived in the Xiongnu pasturelands, but at first they did not mix with the Xiongnu. To be a Xiongnu, one had to be a member of a clan, born of Xiongnu parents. The newcomers were well off, but were outsiders, and could marry only among themselves, not the Xiongnu. Only later did they intermix, increase in numbers, even created a state that existed from 318 to 350 AD.
Origin of the Huns
There are, however, potential problems with equating the names "Xiōngnú" and "Hun". Maenchen-Helfen notes that the Chinese transcription is only an approximation of their actual name. As proof of its imprecision, he notes that Emperor Wang Mang actually renamed the Xiongnu as the Hsiang-nu, with the first element meaning "to submit", while on bad terms with the group. Later, when on good terms, he renamed them Kung-nu, with the first element meaning "respectful". Christopher Beckwith, moreover, notes that the pronunciation of Xiongnu in Old Chinese is uncertain. While it was likely pronounced "*χoŋnʊ" or "*χʲoŋnʊ" in Middle Chinese, it is possible it was taken into Old Chinese before the change of initial "s" to "χ", meaning it could correspond to an Iranian name like Saka or "skuδa" (Scythian). E.G. Pulleyblank suggested an Old Chinese pronunciation similar to "*flông-nah" and connected this name to a nomadic people attested in Greek as the Phrounoi ("Φροῦνοι").