Russia's aims in Syria

In stepping up its involvement in the Syrian conflict to include airstrikes and actual troops on the ground Russia has several ways that it can gain a geopolitical advantage.
To begin with, however, a reminder of the basics. For the moment, for Russia, everything is about The Ukraine.
So how does getting involved with Syria influence events in the Ukraine?
There are several potential positive answers to this question for Russia.
Firstly, if they make it impossible for Assad to be overthrown while they are supporting him, then they raise the possibility that the US and the Europeans will have to do a deal with Russia in order to get the outcomes they want in Syria, and, of course, that means that Russia can negotiate for the outcomes they desire in The Ukraine.
Secondly, if the US want to maintain a hard line against Russia and Assad, it is possible that the Europeans or Turkey might start to see the Americans as standing in the way of a settlement, and Russia consequently gains by dividing its opponents (in the Ukrainian context).

Of course, on entering the Syrian civil war the Russians could not know which way the cards would fall as events played out.
It was possible that the US would hold its allies in line through the sheer strength of its global influence, but even if it did so, the Russians would lose nothing by this. Putin's calculation must surely have been that there was little to lose by intervening in Syria and much to gain if things went well.
So far, the Syrian intervention is playing well for the Russians.
In a much publicized UN speech Putin put forward strong arguments for backing the Assad regime as being the shortest way to end the civil war and eradicate the Islamic State. In doing so he managed to make the US look like they are pursuing a foolish policy in trying to fight (almost) all sides at once; a diplomatic coop for Putin

Since then, the massive increase in Syrian refugees trying to find asylum in Europe has further played into the Russians' hands.
In trying to deal with the asylum seekers, the European countries are now being impacted by events in Syria and, regardless of whether they are closing borders or opening arms, they would much rather they didn't have too. Consequently, the Europeans are now much more eager for a quick settlement of the Syrian civil war, and the US must worry that if they don't provide their allies with some prospect of a resolution to the asylum seeker problem soon then the Europeans may well go behind their backs and deal with the Russians independently in an attempt to end the Syrian crisis. This, of course, is all good news for the Russians, their relative influence vis-a-vis the US is strengthening.

Now, with the atrocities which have occurred in France, we have a major European country wishing to do something decisive toward the destruction of the Islamic State. On the face of it, one would have to think that this new impetus toward action in Syria can only improve the Russian position further.

It will be interesting to see in what ways (or even if) the new French resolve (as stated by their president) can alter events on the ground in Syria.