# Efficient Collaboration
The platform supports issue management for R&D collaboration, including issues such as product backlog, iteration, task and bug.
Backlog Backlog refers to the requirements, tasks and bugs that are not included in an iteration and are the main source of issues for later iterations.
Iteration Iteration is the production process to complete a specific goal for the product, that covers requirement analysis, testing and release. The goal can contain requirements, tasks and bugs, which have three stages of not started, in progress and completed. The overall development can be split into a series of short, duration-fixed (such as four weeks) projects, which is called a series of iterations.
Requirement Requirement refers to the user story in which users solve a certain problem or achieve a certain goal. Usually, a requirement is completed in an iteration, and an iteration can contain several requirements.
Task Task refers to the specific activity performed to achieve the product goal of the iteration. Generally, tasks are split from requirements, and one requirement can be split into several tasks.
Bug Bug refers to the issue that does not meet the initial requirements or cannot satisfy the interaction or performance needs.