One should assess the U.S.-Russian encounter this past week in Vietnam at two levels. At the level of Presidents Putin and Trump, to the disappointment of the Russian side, the Americans decided that progress on any of the issues being discussed was not sufficient to justify a formal meeting.
At another level and behind the scenes, representatives of the two countries are working on key issues, such as Ukraine, North Korea, and Syria.
They appear to be making some progress on Syria, and the prospect of agreement on one or two of the three dimensions that they are discussing:
 extending the de-escalation agreement in southwest Syria to other areas,
 managing their military support to opposing sides in the civil war,
 attempting to energize the diplomatic effort in Geneva in pursuit of a political settlement to the conflict) is apparently what Trump referred to when saying that the two countries were close to an agreement on Syria.
From the Russian perspective, perhaps the most notable development did not come as a result of formal negotiations, but as a result of Trump's informal praise of Putin in the context of the issue of Russian interference in last year's U.S. presidential election.