Tu-214R Russia advanced spy plane
The Tu-214R, Russia's most advanced spy plane
How do you monitor a ceasefire that involves nearly 100 armed groups? This is one of the driving criticisms of the recent US-Russia brokered ceasefire deal in Syria.

Since it entered the conflict in September, Russia has built up arguably the best intelligence-gathering operation in Syria. Using both high-tech military systems, as well as an effective spy network, Moscow's success in Syria can be attributed in part to its emphasis on collecting reliable intelligence and acting swiftly to take advantage of it.

But now that the ceasefire has been implemented, Russia is using its intelligence-gathering systems to monitor and maintain the fragile peace in Syria. As Al-Masdar News reports:
Through the use of radar systems, the Russian Armed Forces have been tracking all reported breaches of the ceasefire agreement; this is something that almost all the monitoring countries do not have access to. As a result of their efforts, the Russian Armed Forces have been able to not only track the aggressive behavior of all parties involved, but also mediate when necessary.
Although the article doesn't get into specifics, we think this is an interesting, important point: Without Russian military systems monitoring the situation in Syria, the ceasefire would not be possible.

But what is Russia using to monitor and mediate the fragile truce? A variety of military systems:
Russia has deployed the IL-20 surveillance aircraft, better known by its NATO name "Coot" and roughly equivalent to the U.S. Navy's P-3 Orion, a mainstay of the Pentagon's spy tools. The Russian plane is bristling with high-tech equipment like surveillance radar, electronic eavesdropping gear, and optical and infrared sensors. One of the Kremlin's premier spy planes, it provides Russian forces with a powerful tool for locating rebel units and assigning targets to its fighter planes. In late September, Syrian rebels posted a video purporting to show the plane flying over a battlefield.
And of course, we can't forget the recently deployed Tu-214R, Russia's most advanced spy plane:
[The Tu-214R] can build the EOB (Electronic Order of Battle) of the enemy forces: where the enemy forces are operating, what kind of equipment they are using and, by eavesdropping into their radio/phone communications, what they are doing and what will be their next move.
Although violations have been reported, the ceasefire in Syria is holding. Russia's political clout in Syria -- as well as its formidable military -- could very well deliver peace to the region soon.