There is no such thing as a ceasefire thats going to hold long term for the simple fact Assad wants to remain and the rebels want him gone and of Assad doesn't volunteer to go which after 5 years of fighting I can't see him doing especially now Russia is helping him directly.
We will have a ceasefire but the end of the day the war will not even come close to ending unless Assad either wins outright or is defeated and killed or goes into exile and if Assad looses the war will continue with different factions fighting for power or massacres of groups like the Alewites in revenge for the war.

Best solutions for the US to quietly stop supporting the rebels to help Assad win the war outright then he will bring order again using an iron fist.
Not going to bring democracy to Syria and it might not be a politically correct solution but its the best one if we want to end the fighting long term.

Wishing Sergey Lavrov and John Kerry best of friendships after retirement. These two gentlemen deserved Nobel peace prize. May they turn their memoir of working together into movie like Mr & Mrs Smith. Russian and American differences. However, they don't call each other INFIDELS.