One of the basic components of scrum is the use of iterations to plan work.
What is an iteration?
An iteration is a defined time period that is spent delivering a working product.
How long does an iteration last?
Most scrum iterations last from 2 to 4 weeks although some teams use shorter iterations. The goal is to define a time period that allows you to complete enough work to have working code ready for stakeholder review.
What happens during an iteration?
During each iteration, all the tasks of the software team occur. Requirements are being defined, code is being written, and testing is being performed.
What inputs are needed for an iteration?
In order to have a successful iteration, you need to have your team and product backlog fully flushed out. This will allow the team to hit the ground running.
What are the outputs of an iteration?
The outputs are fully-written and fully-tested code. The team will often demonstrate the working product at the end of each iteration and needs to be ready in case the stakeholders decide to ship/deploy the product.