Ganas as assemblies

Many books of Sanskrit literature have used ganas and sanghas frequently. The famous Sanskrit scholar Panini of 900 BCE has mentioned in his Sanskrit grammar known as Aṣṭādhyāyī in the form of shloka as जट झट संघाते or Jat Jhat Sanghate. This means that the terms 'Jat' and 'democratic federation' are synonymous.
Panini in his sanskrit grammar used gana as:
संघोद्घौ गण प्रशंसयो Sanghoddhau gaṇa praśansayo
Narada smriti in sanskrit mentions as:
आदि शब्दों गण संघादि समूह विपक्षया Ādi śabdon gaṇa sanghadi samūh vipakshayā
It shows that the ganatantra (republic) system of rule was prevalent in India since ancient period.

Ganas in Shanti Parva
A detailed analysis has been done about ganas in chapter 108 of Shanti Parva in which Yudhisthira asks Bhisma about the ganas that how ganas increase, how they defend themselves from the dividing-policy of enemies, what are the techniques to conquer enemies and making the ganas friends, how they hide their secret mantras being in majority. The Bhisma’s answers to these questions have been recorded in the form of shlokas (verses) from 16 – 32 in Shanti Parva.

Ganas in Vedas
Ganas have been narrated in Vedas in the form of assemblies of warriors as is clear from the following sutras of Rigveda (RV 3-26-6):
व्रातं व्रातं गणम् गणम् Vrātam Vrātam gaṇam gaṇam
Gana in brief means an assembly. Ganatantra (republic) means a state run by assemblies.
The representative members of clans were known as ganas and their assembly as sanghas, there chief as ganadhipati or Ganesha and Ganapati.

Ganas in Buddhist literature
The Buddhist literature Mahabagga mentions that:
गण पूरकोवा भविस्सामीति Gaṇa pūrkovā bhavissāmīti
It indicates that there was an officer who used to see the number of ganas and their koram in the Rajasabha (state assembly).
During Buddhist period, the Buddhist books like ‘Pali-pitaka’, Majjhamnikaya, mahabagga, Avadana shataka have mentioned ganas and sanghas many times. During Buddhas period there were 116 republics or ganasanghas in India.
In Buddhist times, Gaṇas were assemblies of the Sanghas, early democratic republics known as Gaṇa-rājyas, literally "rule of the assembly", a term paralleling demo-kratia or soviet republic. The term was revived in Bhārata Gaṇarājya, the official name of the Republic of India.