The two sides are working on a document that establishes a framework for negotiations. The document or memo would set a 60-day window for further talks to resolve matters including the Iran’s nuclear program and Iran’s demands for relief from U.S. economic sanctions.
However, because of the complexity of matters requiring negotiation such retrieving Iran’s 970 pounds of highly enriched uranium, 60 days is pretty aggressive.
In addition, they are going to need to nail down every detail — that’s why treaties take long to negotiate — but the US team doesn’t inspire confidence in that regard. In previous attempts at negotiating other conflicts they haven’t nailed down every detail and those efforts floundered. The recent Iran cease fire is a perfect example. The negotiators didn’t get Lebanon right.