I can build on that a little bit.
The buildup last spring was serious, and there was a lot of concerted diplomacy from the G7, NATO and European partners. Following that, Russia did eventually de-escalate tensions and pull back the majority of its troops from Ukraine's borders, but the intelligence picture around the current buildup is quite different.
During the spring buildup, Russia attempted to justify its presence on the basis of exercises. This time no justification of any sort has been offered for the positioning of almost a third of Russia's land forces on the border with Ukraine. As the major-general has just said, the other major change now is that Russia is demanding legally binding security guarantees that would constrain Ukraine's options into the future. This is new, and this is the subject of ongoing diplomacy at this time.