What are major elements of the social structure of Pakistan?

The traditional tribes of Pakistan, located principally in the North West Frontier Province, play a central role in the social identity of their members and, as a result, the social structure of this part of Pakistan. In many cases, a tribal members' political identity is first that of a member of his clan and, secondly, as a citizen of Pakistan.
Outside of the tribal regions, Barādarī—a form of caste identity—plays the dominant role in social structures to the point that political parties and politicians in the country more often draw their support from caste fellows than along ideological lines.
Finally, religion is a major factor in the social structure of Pakistan. Islam is the official, state religion of Pakistan and as much as 99% of the country are Muslim, with Sunni Islam being the dominant variety.

Pakistani society is deeply divided along religious, ethnic, and status lines. The state is composed of four provinces: Punjab (the largest), Sindh, North Western Frontier Province (NWFP), and Baluchistan. The largest ethnic groups are Punjabis (about forty-five percent of the total population), Pashtuns (fifteen percent), and Sindhis (fourteen percent).
While in Punjab the caste frameworks (biradri) play a key role in shaping social interactions, in the rest of the country, tribal structures are more important. Tribal chiefs and large landowners hold most political positions and use their influence to their own advantage. Industrialists, many of them Muslim migrants from India, have less political power than traditional tribal and feudal elites.
Inequality and the social exclusion of landless laborers, tenants, and members of the lower caste is a basic feature of social life that the state does little to change. There is also huge gender inequality; males have considerably more access to education and enjoying the dominant position in society.
The role of religion is very important in Pakistan. Three quarters of the country’s population are Sunni Muslims and about twenty percent are Shia. Sectarian tensions are strong; sometimes there are violent attacks on Shia mosques. The ongoing conflict with India over the Kashmir region, which both countries claim, and the war in neighboring Afghanistan have strengthened the influence of Islamic extremists and radical terrorist organizations; these organizations sometimes attack cities, state institutions, and army bases. The social role of the army and the secret services is also very important, as military regimes have governed Pakistan for about half of its independent existence.