There was only an unwritten indirect understanding between the two sides during which time Hamas was arming itself with Iranian weapons smuggled into Gaza. Hamas broke this "cease fire" by trying to build a cross border tunnel into Israel for the purpose of sending terrorists into Israel. The IDF destroyed that tunnel and Hamas retaliated by firing rockets at Israeli civilians. Hamas refused to renew the cease fire and escalated it's missile fire to nearly100 per day. That is what precipitated Cast Lead.
Ofir Akunis officially replaces Danny Danon as minister of science, technology, and space (Haaretz)
from the article: Goldstone has paved the path for a second Gaza war