ISIS is growing at the pace of rabbits.
ISIS/ISIL/IS is a fundamentalist group, made of delusional individuals, who claim to be religious, and who want to create a nation state of Sunni Salafist muslims. Their ultimate aim to wield their power over such vast and rich land is laughable and disturbing to every Indian who has heard of them (yes, not every Indian has heard of them).
The United Nations has recognized ISIS to be a terrorist group by passing a resolution to that effect. If ISIS flexes its forces to come to India, one can speculate that the UN's stand against ISIS will become more sharp and decisive (with Obama saying "I told you so" in the background).
Likewise, India has banned the terror group. India, however, is confused for the most part about how to go about labeling this fundamentalist group. We have hostages under the ISIS, and we would really like to have our people back in India, away from the brutal captors, before doing anything too loud against the ISIS. Thus, one can go so far as to say that this hostage situation is already a mark of the threat that India is facing, from the group.
Is there a risk of the ISIS coming to India?
They can reach India through land or sea routes. Land routes, funnily enough, are not going to be welcoming to them. Our neighbours, all said and done, are not going to harbor terrorists who threaten even their own cultural ethos (ISIS has shown no mercy to non-Sunni muslims; in fact, they were the first to be affected in the emergence of the Islamic State in Syria and Libya). In any case, providing shelter to ISIS amounts to the ire of Uncle Sam. We know no one like to tick Uncle Sam off. Sea routes are probably their most hassle-free means of getting to India. India, since 26/11 has strengthened and secured her coastal fronts sufficiently (although there is much more to be desired, still). ISIS will have a tougher time reaching India than waging any kind of attack against us.
What if ISIS do get to India?
India's armed forces are dynamic and are trained to fight in different types of terrain, over years - something that the ISIS cannot have done, and will not be able to do. There lies our advantage. Over the last couple of decades, our defense strategy has been hinged on deterrence. Nuclear power has deterred direct war on India. But irrational parties such as the stateless (wannabe nation state) ISIS are hardly going to be deterred by atomic bombs. In the unlikely event that the ISIS unleashes terror at our frontiers, rest assured that our armed forces, and paramilitary forces (if need be), shall be deployed, they will ensure we sleep soundly.
To not seem too complacent, let me add that we do need to be in a position to deploy the necessary amount of forces at the time of need, which can be anytime. For this, we should either equip them sufficiently or relieve them of their domestic duty, by settling domestic problems as soon as possible (for example, the recent deplorable massacre of Adivasis in Assam which needed the Indian Army's presence to be quelled).
In the periphery, people have to be made aware of the foolishness of the ideological beliefs that ISIS espouses. There have been worrisome reports of Indians joining the fundamentalist groups. This has to prevented at all costs - a stitch in time saves nine.