Syria battle map 8-22-2017
The length of the Syrian-ISIS front line is about to be radically shortened and many units freed up for a final push into Deir ez-Zor.

As is often the case with Syria there are contradictory reports. According to some the cauldron is not yet fully formed but the final assault to close the last remaining 3-4 kilometers is already underway.

Syria's elite Tiger Forces, backed by Russian helicopters have made contact with the Russian-trained 5th Corps of the Syrian army just north of Suknah.

This means a second ISIS cauldron has now been created in central Syria inside of a week.

This second pocket stretches over an area which is sparsely populated, but is very rugged with many steep hills.

The previous problem for the Syrian army was that advances in the south and along the Euphrates expanded the length of its front line against ISIS to over 600 kilometers. When the two pockets are eliminated or cut down to size the front line against ISIS will be under 300 kilometers long freeing many units for a push into Deir ez-Zor province.
Syria battle map 8/22/2017
ISIS has been reduced to a small corner in the south-east of Syria.
South Front has a good video report:

Meanwhile the retired US colonel Peter Lang over at the Sic Semper Tyrannis blog describes the impressive Russian-Syrian airborne assault that paved the way for the advance that closed the 2nd cauldron:
In the early morning hours of 12 August, Brigadier General Suheil al-Hassan was preparing a company-sized assault force of the Special Airborne Force for a night airmobile assault some twenty kilometers behind IS lines.

This Special Airborne force is not part of Hassan's Tiger Forces. Before the recent unpleasantness in Syria began, they were primarily used for defense of airports but had a great deal of training in urban warfare and counter insurgency. Suheil served as a paratrooper and commander in this unit before forming the Tigers.

Suheil al-Hassan personally led this assault force on this mission. He was seen exhorting his troops on the tarmac wearing a load bearing equipment vest, a helmet with night vision goggles and an AK with night sight under his arm. His troops were also lightly armed with a basic load of ammunition for their small arms, many carried what appear to a LAW-type launcher slung across their backs.

The lightness of their loads were apparent as they ran and jumped up into the Mi-8 helicopter transports. I also note the rear doors of the Hips were removed reminiscent of those Hueys in the 25th Infantry Division. I didn't know they had doors until I got back to Benning.

The operation began with a "fire attack" of multiple rocket launchers (MLRS) followed by an aerial assault by Ka-52 Alligators. The Alligators also adjusted MLRS fire. Then four Hips brought in Suheil's men landing near the settlements of Khirbet Mikman and Al Kadir. They moved along a dry river bed to take a commanding hill and assaulted the village of Al Kadir. Suheil's men took an IS headquarters and several depots.

Suheil and his men held these positions until Tiger Forces advanced to relieve them later in the morning of 12 August. The IS lost over thirty of its fighters, three tanks, seventeen armed tacticals and seven VBIEDs to destruction by the raiding force and a further two VBIEDs and several artillery pieces captured by Suheil's men. There were no SAA casualties from this entire operation.