Mini-update.
From the coordination center which includes Russia, Syria, Iran and Hezbollah, very strange comments are coming.
1) Syria will receive the S-300 very soon, thus gaining the ability to close it's sky to intruders. All planes that don't coordinate with Damascus will be considered hostile. Countries fighting terrorism will be granted air corridors.
2) Iran is preparing two squadrons of Sukhois for action in Syria (Su-24s no doubt - panzerbar's remark)
3) Russian Pantsyr, S-400, and Tor SAMs are in country, and the Sha'aryat airfield is being prepared to receive Russian planes.
4) Iran will be deploying 4000 Revolutionary Guard to Syria with mortars and grenade launchers to provide support.
Ð*оÑÑÐ¸Ñ + Иран = СириÑ? - Берлога Бронемедведа
Personal comment: That's quite a lot, and if I can get confirmation, it means a serious escalation in the war on ISIS. It also means that the Russian-led coalition will become a reality on the ground. 4000 Revolutionary Guard is a major injection of troops, especially if it occurs at a single location. Squadrons of Iranian jets, when all the airspace control assets are Russian, will likely have to not just coordinate for practically take orders from Russian command. And a second Russian base will mean that Russia intends to expand their presence. Iran is not taking over, but providing additional assets.